Sample records for carbonyl allylation propargylation

  1. Catalytic enantioselective 1,6-conjugate additions of propargyl and allyl groups (United States)

    Meng, Fanke; Li, Xiben; Torker, Sebastian; Shi, Ying; Shen, Xiao; Hoveyda, Amir H.


    Conjugate (or 1,4-) additions of carbanionic species to α,β-unsaturated carbonyl compounds are vital to research in organic and medicinal chemistry, and there are several chiral catalysts that facilitate the catalytic enantioselective additions of nucleophiles to enoates. Nonetheless, catalytic enantioselective 1,6-conjugate additions are uncommon, and ones that incorporate readily functionalizable moieties, such as propargyl or allyl groups, into acyclic α,β,γ,δ-doubly unsaturated acceptors are unknown. Chemical transformations that could generate a new bond at the C6 position of a dienoate are particularly desirable because the resulting products could then be subjected to further modifications. However, such reactions, especially when dienoates contain two equally substituted olefins, are scarce and are confined to reactions promoted by a phosphine-copper catalyst (with an alkyl Grignard reagent, dialkylzinc or trialkylaluminium compounds), a diene-iridium catalyst (with arylboroxines), or a bisphosphine-cobalt catalyst (with monosilyl-acetylenes). 1,6-Conjugate additions are otherwise limited to substrates where there is full substitution at the C4 position. It is unclear why certain catalysts favour bond formation at C6, and—although there are a small number of catalytic enantioselective conjugate allyl additions—related 1,6-additions and processes involving a propargyl unit are non-existent. Here we show that an easily accessible organocopper catalyst can promote 1,6-conjugate additions of propargyl and 2-boryl-substituted allyl groups to acyclic dienoates with high selectivity. A commercially available allenyl-boron compound or a monosubstituted allene may be used. Products can be obtained in up to 83 per cent yield, >98:2 diastereomeric ratio (for allyl additions) and 99:1 enantiomeric ratio. We elucidate the mechanistic details, including the origins of high site selectivity (1,6- versus 1,4-) and enantioselectivity as a function of the catalyst

  2. Thermosetting composite matrix materials based on allyl and/or propargyl substituted cyclopentadiene, indene and fluorene (United States)

    Tregre, Gregory Jude

    A series of all-hydrocarbon thermoset composite matrix resins was synthesized via electrophilic substitution of cyclopentadiene, indene, and fluorene ring systems with allyl and/or propargyl halides under phase transfer conditions. Reaction of cyclopentadiene with allyl chloride (ACP resin), propargyl bromide (PCP resin) or various feed ratios of allyl chloride and propargyl bromide (APCP resins) yielded mixtures of products with 2-6 substituents per cyclopentadiene ring. Reaction of indene with allyl chloride (Al resins) or propargyl bromide (PI resins) yielded mixtures of products with 2-4 substituents per indene. In both sets of resins the allyl functionality obtained a greater average degree of substitution than the analogous propargyl species. Differential scanning calorimetric (DSC) analysis of the multifunctional resins showed broad, high-energy thermal cures in all cases. The enthalpies of cure for ACP and PCP were 750 J/g and 805 J/g, respectively, with peak cure energies occurring at 310 and 248sp°C. The enthalpy of cure for APCP resins ranged from 750 J/g to 800 J/g with higher propargyl-functional resins yielding higher enthalpies of cure. Physically mixed ACP/PCP resin systems gave peak cure temperatures and energy values comparable to APCP resins. The enthalpies of cure for Al and PI-resins were 480 J/g and 630 J/g, respectively. Peak cure temperature for Al resin was 320sp°C, while the peak cure for PI resin occurred at 282sp°C. Infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR) were used to evaluate mechanisms of cure in the experimental resins. The allyl functional resins cured through a combination of ene reactions and polyaddition reactions. The propargyl functional resins cured through ene reactions and polyadditions but also underwent some cyclotrimerization of the propargyl functionalities. A small amount of autoxidation was seen in all of the resins. Thermal stability and carbon yields of the cured resins were

  3. Ruthenium Catalyzed Diastereo- and Enantioselective Coupling of Propargyl Ethers with Alcohols: Siloxy-Crotylation via Hydride Shift Enabled Conversion of Alkynes to π-Allyls (United States)

    Liang, Tao; Zhang, Wandi; Chen, Te-Yu; Nguyen, Khoa D.; Krische, Michael J.


    The first enantioselective carbonyl crotylations through direct use of alkynes as chiral allylmetal equivalents are described. Chiral ruthenium(II) complexes modified by Josiphos (SL-J009-1) catalyze the C-C coupling of TIPS-protected propargyl ether 1a with primary alcohols 2a-2o to form products of carbonyl siloxy-crotylation 3a-3o, which upon silyl deprotection-reduction deliver 1,4-diols 5a-5o with excellent control of regio-, anti-diastereo- and enantioselectivity. Structurally related propargyl ethers 1b and 1c bearing ethyl- and phenyl-substituents engage in diastereo- and enantioselective coupling, as illustrated in the formation of adducts 5p and 5q, respectively. Selective mono-tosylation of diols 5a, 5c, 5e, 5f, 5k and 5m is accompanied by spontaneous cyclization to deliver the trans-2,3-disubstituted furans 6a, 6c, 6e, 6f, 6k and 6m, respectively. Primary alcohols 2a, 2l and 2p were converted to the siloxy-crotylation products 3a, 3l and 3p, which upon silyl deprotection-lactol oxidation were transformed to the trans-4,5-disubstituted γ-butyrolactones 7a, 7l and 7p. The formation of 7p represents a total synthesis of (+)-trans-whisky lactone. Unlike closely related ruthenium catalyzed alkyne-alcohol C-C couplings, deuterium labeling studies provide clear evidence of a novel 1,2-hydride shift mechanism that converts metal-bound alkynes to π-allyls in the absence of intervening allenes. PMID:26418572

  4. Green Synthesis and Regioselective Control of Sn/I2 Mediated Allylation of Carbonyl Compounds with Crotyl Halide in Water

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Yan; ZHA,Zhang-Gen; ZHOU,Yu-Qing; WANG,Zhi-Yong


    @@ Barbier-type carbonyl allylation is particularly useful due to ease of operation and the availability and tractability of allylic substrates,[1] Metals such as indium, zinc and tin are often used as the mediator. Here we present a green approach toward the synthesis, that is, Sn/I2 mediated allylation of carbonyl compounds with crotyl halide in water.

  5. Double Conjugate Addition of Dithiols to Propargylic Carbonyl Systems To Generate Protected 1,3-Dicarbonyl Compounds

    NARCIS (Netherlands)

    Sneddon, Helen F.; Heuvel, Alexandra van den; Hirsch, Anna K.H.; Booth, Richard A.; Shaw, David M.; Gaunt, Matthew J.; Ley, Steven V.


    The work describes the efficient double conjugate addition of ethane and propane dithiols in the presence of sodium methoxide to a wide variety of propargylic carbonyl containing compounds. The products of these reactions are differentiated, 1,3-dicarbonyl systems useful for various synthesis progra

  6. Nano-Aluminum Powder Mediated Allylation of Carbonyl Compounds in Aqueous Media

    Institute of Scientific and Technical Information of China (English)

    YUAN Shi-Zhen; LIU Jin


    A new and effective Barbier-Grignard allylation of aldehydes or ketones has been carried out with nano-aluminum powder in aqueous 0.1 mol·L-1 NH4Cl (aq.) under an atmosphere of nitrogen. Aromatic carbonyl compounds gave homoallylic alcohols in good yields. The effectiveness of reaction was strongly influenced by the steric environment surrounding the carbonyl group. Aliphatic carbonyl compounds proceeded in low yields. The dominant stereoisomer was an erythro-isomer when an ortho-hydroxyl carbonyl compound was reacted under such a reaction condition.

  7. Facile coupling of propargylic, allylic and benzylic alcohols with allylsilane and alkynylsilane, and their deoxygenation with Et3SiH, catalyzed by Bi(OTf)3 in [BMIM][BF4] ionic liquid (IL), with recycling and reuse of the IL. (United States)

    Kumar, G G K S Narayana; Laali, Kenneth K


    Allyltrimethylsilane (allyl-TMS) reacts with propargylic alcohols 1a-1d in the presence of 10% Bi(OTf)(3) in [BMIM][BF(4)] solvent to furnish the corresponding 1,5-enynes in respectable isolated yields (87-93%) at room temperature. The utility of Bi(OTf)(3) as a superior catalyst was demonstrated in a survey study on coupling of allyl-TMS with employing several metallic triflates (Bi, Ln, Al, Yb) as well as, B(C(6)F(5))(3), Zn(NTf(2))(2) and Bi(NO(3))(3)·5H(2)O. Coupling of cyclopropyl substituted propargylic alcohol with allyl-TMS gave the skeletally intact 1,5-enyne and a ring opened derivative as a mixture. Coupling of propargylic/allylic alcohol with allyl-TMS resulted in allylation at both benzylic (2 isomers) and propargylic positions, as major and minor products respectively. The scope of this methodology for allylation of a series of allylic and benzylic alcohols was explored. Chemoselective reduction of a host of propargylic, propagylic/allylic, bis-allylic, allylic, and benzylic alcohols with Et(3)SiH was achieved in high yields with short reaction times. The same approach was successfully applied to couple representative propargylic and allylic alcohols with 1-phenyl-2-trimethylsilylacetylene. The recovery and reuse of the ionic liquid (IL) was gauged in a case study with minimal decrease in isolated yields after six cycles.

  8. Catalyst- and solvent-dependent stereodivergence in the intramolecular Et(2)Zn/Pd(0) -promoted carbonyl propargylation: mechanistic implications. (United States)

    Arrate, Mónica; Durana, Aritz; Lorenzo, Paula; de Lera, Ángel R; Álvarez, Rosana; Aurrecoechea, José M


    Carbonyl-tethered propargylic benzoates undergo intramolecular carbonylpropargylation upon treatment with Et2 Zn in the presence of a catalytic amount of Pd(0) with the formation of 2-alkynylcyclopentanol products. A ligand/solvent effect on the cis/trans selectivity (referring to the relative positions of alkynyl and OH groups) of ring-closure has been found. In a non-coordinating solvent (benzene), increasing the electron-donating ability of the phosphine ligand (while decreasing its dissociation ability) leads to an increased tendency towards the trans product. On the other hand, the combination of a coordinating solvent (THF) and PPh3 , an easily dissociated phosphine, results in the exclusive formation of cis products. Experimental and computational results are compatible with a divergent behavior of an allenylethylpalladium intermediate that partitions between competitive carbonyl-addition and transmetalation pathways, each leading to a different diastereoisomer. These results also suggest that the dissociating ability of the phosphine regulates that behavior.

  9. Direct Substitution of the Hydroxy Group at the Allylic/propargylic Position with Carbon-and Heteroatomcentered Nucleophiles Catalyzed by Yb(OTf)3

    Institute of Scientific and Technical Information of China (English)

    HUANG Wen; SHEN Quan-Sheng; WANG Jia-Liang; ZHOU Xi-Geng


    An efficient and highly selective Yb(OTf)3-catalyzed direct substitution of the hydroxy group at the allylic and propargylic positions with a variety of heteroatom- and carbon-centered nucleophiles, such as alcohols, thiols,amines, amides and active methylene compounds has been developed. The advantages of the present catalytic system are wide availability of the starting materials, especially for tolerance to thiols, no need for dried solvents and additives, mild conditions, short time of reaction, simple manipulation and environmentally friendly catalyst that can be recovered and reused at least ten times without significant reduction of activity.

  10. Multimetallic complexes and functionalized nanoparticles based on unsymmetrical dithiocarbamate ligands with allyl and propargyl functionality. (United States)

    Hurtubise, Venesia L; McArdle, James M; Naeem, Saira; Toscani, Anita; White, Andrew J P; Long, Nicholas J; Wilton-Ely, James D E T


    The new, unsymmetrical dithiocarbamate ligands, KS2CN(CH2CH═CH2)Me and KS2CN(CH2C≡CH)Me, are formed from the respective amines on reaction with KOH and carbon disulfide. The homoleptic complexes [Ni{S2CN(CH2CH═CH2)Me}2] and [M{S2CN(CH2C≡CH)Me}2] (M = Ni, Pd, Pt) are formed on reaction with suitable metal precursors. Conversion between the two pendant functionalities was confirmed by hydrogenation of [Ni{S2CN(CH2C≡CH)Me}2] to yield [Ni{S2CN(CH2CH═CH2)Me}2]. The monodithiocarbamate compounds of group 8, 10, and 11 metals, [Ru{S2CN(CH2CH═CH2)Me}(dppm)2](+), [Ru(CH═CHC6H4Me-4){S2CN(CH2CH═CH2)Me}(CO)(PPh3)2], [Ni{S2CN(CH2CH═CH2)Me}(dppp)](+), and [Au{S2CN(CH2CH═CH2)Me}(PPh3)] were formed successfully. Using KS2CN(CH2C≡CH)Me, the complex [Ru{S2CN(CH2C≡CH)Me}(dppm)2](+) was obtained from cis-[RuCl2(dppm)2]. One palladium example, [Pd{S2CN(CH2C≡CH)Me}(PPh3)2](+), was also isolated in low yield. However, under the typical conditions employed, a rearrangement reaction prevented isolation of further group 10 propargyl-dithiocarbamate products. Over the extended reaction time required, Me(HC≡CCH2)NCS2(-) was found to undergo a remarkable, atom-efficient cyclization to form the thiazolidine-2-thione, H2C═CCH2N(Me)C(═S)S, in high yield, with MeC═CHN(Me)C(═S)S as the minor product. The reactivity of the pendant triple bonds in [Ni{S2CN(CH2C≡CH)Me}2] was probed in the reaction with [RuH(CO)(S2P(OEt)2)(PPh3)2] to form the trimetallic example [Ni{S2CN(Me)CH2CH═CHRu(CO)(S2P(OEt)2)(PPh3)2}2], while the copper(I) catalyzed reaction with benzylazide yielded the triazole product, [Ni{S2CN(Me)CH2(C2HN3)Bz}2]. KS2CN(CH2C≡CH)Me was also used to prepare the gold nanoparticles, Au@S2CN(CH2C≡CH)Me. Structural studies are reported for [Ru(CH═CHC6H4Me-4){S2CN(CH2CH═CH2)Me}(CO)(PPh3)2] and [Ru{S2CN(CH2C≡CH)Me}(dppm)2]PF6.

  11. SnCl2/Cu-Mediated Carbonyl Allylation Reaction in Water:Scope,Selectivity and Mechanism

    Institute of Scientific and Technical Information of China (English)

    TAN,Xiang-Hui(谭翔晖); HOU,Yong-Quan(侯永泉); LIU,Lei(刘磊); GUO,Qing-Xiang(郭庆祥)


    Copper was found to be able to promote the SnC12-mediated carbonyl allylation reactions in water,giving the corresponding homoallylic alcohol products in very high yields.Detailed studies showed that the reaction could be applied to a variety of carbonyl compounds including those with hydroxyl,amino and nitro groups.It was also found that this reaction showed good regioselectivities for some substrates.Furthermore,carefully controled experiments and in situ NMR measurements provided important insights into the mechanism of the newly developed reaction.

  12. Crystallization experiments with the dinuclear chelate ring complex di-μ-chlorido-bis[(η(2)-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC(1))platinum(II)]. (United States)

    Nguyen Thi Thanh, Chi; Pham Van, Thong; Le Thi Hong, Hai; Van Meervelt, Luc


    Crystallization experiments with the dinuclear chelate ring complex di-μ-chlorido-bis[(η(2)-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC(1))platinum(II)], [Pt2(C15H19O4)2Cl2], containing a derivative of the natural compound eugenol as ligand, have been performed. Using five different sets of crystallization conditions resulted in four different complexes which can be further used as starting compounds for the synthesis of Pt complexes with promising anticancer activities. In the case of vapour diffusion with the binary chloroform-diethyl ether or methylene chloride-diethyl ether systems, no change of the molecular structure was observed. Using evaporation from acetonitrile (at room temperature), dimethylformamide (DMF, at 313 K) or dimethyl sulfoxide (DMSO, at 313 K), however, resulted in the displacement of a chloride ligand by the solvent, giving, respectively, the mononuclear complexes (acetonitrile-κN)(η(2)-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC(1))chloridoplatinum(II) monohydrate, [Pt(C15H19O4)Cl(CH3CN)]·H2O, (η(2)-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC(1))chlorido(dimethylformamide-κO)platinum(II), [Pt(C15H19O4)Cl(C2H7NO)], and (η(2)-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κC(1))chlorido(dimethyl sulfoxide-κS)platinum(II), determined as the analogue {η(2)-2-allyl-4-methoxy-5-[(ethoxycarbonyl)methoxy]phenyl-κC(1)}chlorido(dimethyl sulfoxide-κS)platinum(II), [Pt(C14H17O4)Cl(C2H6OS)]. The crystal structures confirm that acetonitrile interacts with the Pt(II) atom via its N atom, while for DMSO, the S atom is the coordinating atom. For the replacement, the longest of the two Pt-Cl bonds is cleaved, leading to a cis position of the solvent ligand with respect to the allyl group. The crystal packing of the complexes is characterized by dimer formation via C-H...O and C-H...π interactions, but no π-π interactions are observed despite the presence of

  13. Allylation of Aromatic Aldehyde under Microwave Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Yu-Mei; JIA,Xue-Feng; WANG,Jin-Xian


    @@ Allylation of carbonyl compounds is one of the most interesting processes for the preparation of homoallylic alcohols. Over the past few decades, many reagents have been developed for such reactions[1~3]. In this paper, we first report allylic zinc reagent 1, which can be prepared from zinc dust and allyl bromide conveniently in THF, and reacted with aromatic aldehyde to give homo-allylic alcohols under microwave irradiation.

  14. Transition metal catalysed Grignard-like allylic activation across tetragonal tin(II) oxide

    Indian Academy of Sciences (India)

    Pradipta Sinha; Moloy Banerjee; Abhijit Kundu; Sujit Roy


    The reaction of allyl halide and a carbonyl compound under the aegis of tetragonal tin(II) oxide and catalytic 8, 10 metal complexes provides the corresponding homoallylic alcohol, via a novel allyl tin intermediate.

  15. Allyl 4-hydroxyphenyl carbonate

    Directory of Open Access Journals (Sweden)

    Víctor Hugo Flores Ahuactzin


    Full Text Available The title molecule, C10H10O4, is a functionalized carbonate used in the synthetic route to organic glasses. The central CH fragment of the allyl group is disordered over two positions, with occupancies in a 0.758 (10:0.242 (10ratio. This disorder reflects the torsional flexibility of the oxygen–allyl group, although both disordered parts present the expected anticlinal conformation, with O—CH2—CH=CH2 torsion angles of −111 (2 and 119.1 (4°. The crystal structure is based on chains parallel to [010], formed by O...H—O hydrogen bonds involving hydroxyl and carbonyl groups as donors and acceptors, respectively. The molecular packing is further stabilized by two weak C—H...π contacts from the benzene ring of the asymmetric unit with two benzene rings of neighboring molecules.

  16. Rhodium(I)-Catalyzed Benzannulation of Heteroaryl Propargylic Esters: Synthesis of Indoles and Related Heterocycles. (United States)

    Li, Xiaoxun; Xie, Haibo; Fu, Xiaoning; Liu, Ji-Tian; Wang, Hao-Yuan; Xi, Bao-Min; Liu, Peng; Xu, Xiufang; Tang, Weiping


    A de novo synthesis of a benzene ring allows for the preparation of a diverse range of heterocycles including indoles, benzofurans, benzothiophenes, carbazoles, and dibenzofurans from simple heteroaryl propargylic esters using a unified carbonylative benzannulation strategy. Multiple substituents can be easily introduced to the C4-C7 positions of indoles and related heterocycles.

  17. Synthesis of Carbazoles and Carbazole-Containing Heterocycles via Rhodium-Catalyzed Tandem Carbonylative Benzannulations. (United States)

    Song, Wangze; Li, Xiaoxun; Yang, Ka; Zhao, Xian-liang; Glazier, Daniel A; Xi, Bao-min; Tang, Weiping


    Polycyclic aromatic compounds are important constituents of pharmaceuticals and other materials. We have developed a series of Rh-catalyzed tandem carbonylative benzannulations for the synthesis of tri-, tetra-, and pentacyclic heterocycles from different types of aryl propargylic alcohols. These tandem reactions provide efficient access to highly substituted carbazoles, furocarbazoles, pyrrolocarbazoles, thiophenocarbazoles, and indolocarbazoles. While tricyclic heterocycles could be derived from vinyl aryl propargylic alcohols, tetra- and pentacyclic heterocycles were synthesized from diaryl propargylic alcohols. The tandem carbonylative benzannulation is initiated by a π-acidic rhodium(I) catalyst-mediated nucleophilic addition to alkyne to generate a key metal-carbene intermediate, which is then trapped by carbon monoxide to form a ketene species for 6π electrocyclization. Overall, three bonds and two rings are formed in all of these tandem carbonylative benzannulation reactions.

  18. Propargylation of arabinogalactan with propargyl halides--a facile route to new functionalized biopolymers. (United States)

    Grischenko, Lyudmila A; Parshina, Lidiya N; Kanitskaya, Lyudmila V; Larina, Lyudmila I; Novikova, Lyubov N; Trofimov, Boris A


    New arabinogalactan propargyl ethers with degree of substitution (DS) up to 2.8 have been obtained by propargylation of arabino-3,6-galactan (AG) with propargyl bromide (PB) in the two-phase system 30-60% КОН aqueous solution/toluene in the presence of triethylbenzylammonium chloride (TEBAС) or without catalyst (ambient temperature, 1-24 h) in 20-87% yields. The highest yields have been reached using TEBAС as phase-transfer catalyst, though the non-catalytic version proves to be also efficient (DS 2.8, 70% yield). The propargylation of AG is less effective in the systems MОН (M=Na, K)/DMSO. DS of propargyl AG reaches 1.8 (70% yield) when propargyl chloride is used as propargylating agent, while with PB under the same conditions DS value does not exceed 0.4-0.6, the yields being 44-65%. Under the action of t-BuOK/DMSO system, the AG propargyl ethers have been isomerized to the corresponding unstable allenyl ethers. AG propargyl ethers with DS 2.0 have been almost exhaustively metallated with Ag2O/NH3 system to give AG-Ag acetylides derivatives with Ag/C≡C ratio equaling 0.95.


    NARCIS (Netherlands)

    Rispens, Minze T.; Zondervan, Charon; Feringa, Bernard


    Several chiral Cu(II)-complexes of cyclic amino acids catalyse the enantioselective allylic oxidation of cyclohexene to cyclohexenyl esters. Cyclohexenyl propionate was obtained in 86% yield with e.e.'s up to 61%.

  20. Synthesis of acrylic and allylic bifunctional cross-linking monomers derived from PET waste (United States)

    Cruz-Aguilar, A.; Herrera-González, A. M.; Vázquez-García, R. A.; Navarro-Rodríguez, D.; Coreño, J.


    An acrylic and two novel allylic monomers synthesized from bis (hydroxyethyl) terephthalate, BHET, are reported. This was obtained by glycolysis of post-consumer PET with boiling ethylene glycol. The bifunctional monomer bis(2-(acryloyloxy)ethyl) terephthalate was obtained from acryloyl chloride, while the allylic monomers 2-(((allyloxi)carbonyl)oxy) ethyl (2-hydroxyethyl) terephthalate and bis(2-(((allyloxi)carbonyl)oxy)ethyl) terephthalate, from allyl chloroformate. Cross-linking was studied in bulk polymerization using two different thermal initiators. Monomers were analyzed by means of 1H NMR and the cross-linked polymers by infrared spectroscopy. Gel content higher than 90% was obtained for the acrylic monomer. In the case of the mixture of the allylic monomers, the cross-linked polymer was 80 % using BPO initiator, being this mixture 24 times less reactive than the acrylic monomer.

  1. Direct Conversion of Aldehydes and Ketones to Allylic Halides by a NbX(5-)[3,3] Rearrangement. (United States)

    Fleming, Fraser F; Ravikumar, P C; Yao, Lihua


    Sequential addition of vinylmagnesium bromide and NbCl(5), or NbBr(5), to a series of aldehydes and ketones directly provides homologated, allylic halides. Transposition of the intermediate vinyl alkoxide is envisaged through a metalla-halo-[3,3] rearrangement with concomitant delivery of the halogen to the terminal carbon. The [3,3] rearrangement is equally effective for the conversion of a propargyllic alcohol to the corresponding allenyl bromide.

  2. Direct Conversion of Aldehydes and Ketones to Allylic Halides by a NbX5-[3,3] Rearrangement (United States)

    Fleming, Fraser F.; Ravikumar, P. C.; Yao, Lihua


    Sequential addition of vinylmagnesium bromide and NbCl5, or NbBr5, to a series of aldehydes and ketones directly provides homologated, allylic halides. Transposition of the intermediate vinyl alkoxide is envisaged through a metalla-halo-[3,3] rearrangement with concomitant delivery of the halogen to the terminal carbon. The [3,3] rearrangement is equally effective for the conversion of a propargyllic alcohol to the corresponding allenyl bromide. PMID:20046989

  3. Propargyl-functional aliphatic polycarbonate obtained from carbon dioxide and glycidyl propargyl ether. (United States)

    Hilf, Jeannette; Frey, Holger


    The synthesis of propargyl-functional poly(carbonate)s with different content of glycidyl propargyl ether (GPE) units is achieved via the copolymerization of propargyl glycidyl ether and carbon dioxide. A new type of functional poly(carbonate) synthesized directly from CO(2) and the glycidyl ether is obtained. The resulting polymers show moderate polydispersities in the range of 1.6-2.5 and molecular weights in the range of 7000-10 500 g mol(-1). The synthesized copolymers with varying number of alkyne functionalities and benzyl azide are used for the copper-catalyzed Huisgen-1,3-dipolar addition. Moreover, the presence of vicinal alkyne groups opens a general pathway to produce functional aliphatic poly(carbonate)s from a single polymer scaffold.

  4. Regioselective Propargylation of Aldehydes with Propargyl Bromide Mediated by Sn-In in Aqueous Media under Microwave Irradiation

    Institute of Scientific and Technical Information of China (English)

    Cheng Zhi GU; Qian Rong LI; Hao YIN


    Tin-indium were employed in the propargylations of various aldehydes with propargyl bromide in the presence of SnCl2 and C6 H5(CH3)3NBr under microwave irradiation to afford the corresponding homopropargyl alcohols exclusively in high yields. All the reactions were completed smoothly in predominantly aqueous media in 200 seconds only.


    Energy Technology Data Exchange (ETDEWEB)

    Sivaraman, B.; Mukherjee, R.; Subramanian, K. P.; Banerjee, S. B., E-mail: [Space and Atmospheric Sciences Division, Physical Research Laboratory, Ahmedabad (India)


    Propargyl alcohol (CHCCH{sub 2}OH) is a known stable isomer of the propenal (CH{sub 2}CHCHO) molecule that was reported to be present in the interstellar medium (ISM). At astrochemical conditions in the laboratory, icy layers of propargyl alcohol grown at 85 K were irradiated by 2 keV electrons and probed by a Fourier Transform InfraRed spectrometer in the mid-infrared (IR) region, 4000-500 cm{sup –1}. Propargyl alcohol ice under astrochemical conditions was studied for the first time; therefore, IR spectra of reported amorphous (85 K) and crystalline (180 K) propargyl alcohol ices can be used to detect its presence in the ISM. Moreover, our experiments clearly show benzene (C{sub 6}H{sub 6}) formation to be the major product from propargyl alcohol irradiation, confirming the role of propargyl radicals (C{sub 3}H{sub 3}) formed from propargyl alcohol dissociation that was long expected based on theoretical modeling to effectively synthesize C{sub 6}H{sub 6} in the interstellar icy mantles.

  6. Tsuji-Trost N-allylation with allylic acetates using cellulose-Pd catalyst (United States)

    Allylic amines are synthesized using heterogeneous cellulose-Pd catalyst via N-allylation of amines; aliphatic and benzyl amines undergo facile reaction with substituted and unsubstituted allyl acetates in high yields.

  7. A Green Approach for Allylations of Aldehydes and Ketones: Combining Allylborate, Mechanochemistry and Lanthanide Catalyst

    Directory of Open Access Journals (Sweden)

    Viviane P. de Souza


    Full Text Available Secondary and tertiary alcohols synthesized via allylation of aldehydes and ketones are important compounds in bioactive natural products and industry, including pharmaceuticals. Development of a mechanochemical method using potassium allyltrifluoroborate salt and water, to successfully perform the allylation of aromatic and aliphatic carbonyl compounds is reported for the first time. By controlling the grinding parameters, the methodology can be selective, namely, very efficient for aldehydes and ineffective for ketones, but by employing lanthanide catalysts, the reactions with ketones can become practically quantitative. The catalyzed reactions can also be performed under mild aqueous stirring conditions. Considering the allylation agent and its by-products, aqueous media, energy efficiency and use of catalyst, the methodology meets most of the green chemistry principles.

  8. A Mechanistic Study of Direct Activation of Allylic Alcohols in Palladium Catalyzed Amination Reactions

    Directory of Open Access Journals (Sweden)

    Yasemin Gumrukcu


    Full Text Available We here report a computational approach on the mechanism of allylicamination reactions using allyl-alcohols and amines as the substrates and phosphoramidite palladium catalyst 1a, which operates in the presence of catalytic amount of 1,3-diethylurea as a co-catalyst. DFT calculations showed a cooperative hydrogen-bonding array between the urea moiety and the hydroxyl group of the allyl alcohol, which strengthens the hydrogen bond between the O-H moiety of the coordinated allyl-alcohol and the carbonyl-moiety of the ligand. This hydrogen bond pattern facilitates the (rate-limiting C-O oxidative addition step and leads to lower energy isomers throughout the catalytic cycle, clarifying the role of the urea-moiety.

  9. Rotational Spectrum of Ar...PROPARGYL Alcohol Complex (United States)

    Mani, Devendra; Shahi, Abhishek; Arunan, E.


    Pure rotational spectrum for Ar...Propargyl alcohol complex has been observed and fitted. Fitted rotational constants for the complex are : A=4346.17307(90) MHz, B=1617.15317(19)MHz and C= 1245.42065(15) MHz. These rotational constants are very close to the ab-initio rotational constants for the geometry, in which propargyl alcohol exists in gauche conformation and Ar interacts with both, the hydroxyl group and the acetylenic group of propargyl alcohol. Rotational spectrum of deuterated isotopologue (-OD) of the complex further confirms the existence of the above mentioned geometry. In previous studies tunneling frequency corresponding to -OH tunneling motion in propargyl alocohol monomer was determined to be 652.4 GHz and for -OD tunneling motion in mono-deuterated species, it was 213.5 GHz. In Ar...Propargyl alcohol complex also, a-type and c-dipole transitions show tunneling splitting. In the parent complex, for a-type transitions, tunneling splitting was 10 KHz and for c-type transitions (c-dipole of the complex is in the same direction as in propargyl alcohol monomer, and it is antisymmetric with respect to OH tunneling motion in both monomer and the complex), it was 2.59 MHz. In deuterated complex (OD) splitting was not resolvable for a-type transitions while for c-type it reduces to 900 KHz. Search for C-13 isotopologues is in progress. Moreover, propargyl alcohol offers several possibilities for H-bonding and we are planning to study its complexes with water in near future. Results will be presented in the talk. E. Hirota,J. Mol. Spectrosc. 26 (1968) 335-350. J.C. Pearson, B.J. Drouin, J. Mol. Spectrosc. 234 (2005) 149-156.

  10. Palladium-catalyzed amination of allyl alcohols. (United States)

    Ghosh, Raju; Sarkar, Amitabha


    An efficient catalytic amination of aryl-substituted allylic alcohols has been developed. The complex [(η(3)-allyl)PdCl](2) modified by a bis phosphine ligand, L, has been used as catalyst in the reaction that afforded a wide range of allyl amines in good to excellent yield under mild conditions.

  11. Thermal Decomposition of Furan Generates Propargyl Radicals

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliou, A.; Nimlos, M. R.; Daily, J. W.; Ellison, G. B.


    The thermal decomposition of furan has been studied by a 1 mm x 2 cm tubular silicon carbide reactor, C{sub 4}H{sub 4}O + {Delta} {yields} products. Unlike previous studies, these experiments are able to identify the initial furan decomposition products. Furan is entrained in either He or Ar carrier gas and is passed through a heated (1600 K) SiC tubular reactor. Furan decomposes during transit through the tubular reactor (approximately 65 {micro}s) and exits to a vacuum chamber. Within one nozzle diameter of leaving the nozzle, the gases cool to less than 50 K, and all reactions cease. The resultant molecular beam is interrogated by photoionization mass spectroscopy as well as infrared spectroscopy. Earlier G2(MP2) electronic structure calculations predicted that furan will thermally decompose to acetylene, ketene, carbon monoxide, and propyne at lower temperatures. At higher temperatures, these calculations forecast that propargyl radical could result. We observe all of these species (see Scheme 1). As the pressure in the tubular reactor is raised, the photoionization mass spectra show clear evidence for the formation of aromatic hydrocarbons.

  12. Iridium-Catalyzed Allylic Substitution (United States)

    Hartwig, John F.; Pouy, Mark J.

    Iridium-catalyzed asymmetric allylic substitution has become a valuable method to prepare products from the addition of nucleophiles at the more substituted carbon of an allyl unit. The most active and selective catalysts contain a phosphoramidite ligand possessing at least one arylethyl substituent on the nitrogen atom of the ligand. In these systems, the active catalyst is generated by a base-induced cyclometalation at the methyl group of this substituent to generate an iridium metalacycle bound by the COD ligand of the [Ir(COD)Cl]2 precursor and one additional labile dative ligand. Such complexes catalyze the reactions of linear allylic esters with alkylamines, arylamines, phenols, alcohols, imides, carbamates, ammonia, enolates and enolate equivalents, as well as typical stabilized carbon nucleophiles generated from malonates and cyanoesters. Iridium catalysts for enantioselective allylic substitution have also been generated from phosphorus ligands with substituents bound by heteroatoms, and an account of the studies of such systems, along with a description of the development of iridium catalysts is included.

  13. Design, synthesis and biological evaluation of dinucleotide mRNA cap analog containing propargyl moiety. (United States)

    Shanmugasundaram, Muthian; Charles, Irudaya; Kore, Anilkumar R


    The first example of the synthesis of new dinucleotide cap analog containing propargyl group such as m(7,3'-O-propargyl)G[5']ppp[5']G is reported. The effect of propargyl cap analog with standard cap was evaluated with respect to their capping efficiency, in vitro T7 RNA polymerase transcription efficiency, and translation activity using cultured HeLa cells. It is noteworthy that propargyl cap analog outperforms standard cap by 3.1 fold in terms of translational properties. The propargyl cap analog forms a more stable complex with translation initiation factor eIF4E based on the molecular modeling studies.

  14. Sulfoxide-Directed Metal-Free ortho-Propargylation of Aromatics and Heteroaromatics. (United States)

    Eberhart, Andrew J; Shrives, Harry J; Álvarez, Estela; Carrër, Amandine; Zhang, Yuntong; Procter, David J


    A sulfoxide-directed, metal-free ortho-propargylation of aromatics and heteroaromatics exploits intermolecular delivery of a propargyl nucleophile to sulfur followed by an intramolecular relay to carbon. The operationally simple cross-coupling procedure is general, regiospecific with regard to the propargyl nucleophile, and shows complete selectivity for products of ortho-propargylation over allenylation. The use of secondary propargyl silanes allows metal-free ortho-coupling to form carbon-carbon bonds between aromatic and heteroaromatic rings and secondary propargylic centres. The 'safety-catch' nature of the sulfoxide directing group is illustrated in a selective, iterative double cross-coupling process. The products of propargylation are versatile intermediates and they have been readily converted into substituted benzothiophenes.

  15. HBF4-Catalysed Nucleophilic Substitutions of Propargylic Alcohols


    Barreiro, Elena; Sanz-Vidal, Alvaro; Tan, Eric; Lau, Shing-Hing; Sheppard, Tom D; Díez-González, Silvia


    The activity of HBF4 (aqueous solution) as a catalyst in propargylation reactions is presented. Diverse types of nucleophiles were employed in order to form new C–O, C–N and C–C bonds in technical acetone and in air. Good to excellent yields and good chemoselectivities were obtained using low acid loading (typically 1 mol-%) under simple reaction conditions.

  16. The allylic chalcogen effect in olefin metathesis

    Directory of Open Access Journals (Sweden)

    Yuya A. Lin


    Full Text Available Olefin metathesis has emerged as a powerful tool in organic synthesis. The activating effect of an allylic hydroxy group in metathesis has been known for more than 10 years, and many organic chemists have taken advantage of this positive influence for efficient synthesis of natural products. Recently, the discovery of the rate enhancement by allyl sulfides in aqueous cross-metathesis has allowed the first examples of such a reaction on proteins. This led to a new benchmark in substrate complexity for cross-metathesis and expanded the potential of olefin metathesis for other applications in chemical biology. The enhanced reactivity of allyl sulfide, along with earlier reports of a similar effect by allylic hydroxy groups, suggests that allyl chalcogens generally play an important role in modulating the rate of olefin metathesis. In this review, we discuss the effect of allylic chalcogens in olefin metathesis and highlight its most recent applications in synthetic chemistry and protein modifications.

  17. The allylic chalcogen effect in olefin metathesis (United States)

    Lin, Yuya A


    Summary Olefin metathesis has emerged as a powerful tool in organic synthesis. The activating effect of an allylic hydroxy group in metathesis has been known for more than 10 years, and many organic chemists have taken advantage of this positive influence for efficient synthesis of natural products. Recently, the discovery of the rate enhancement by allyl sulfides in aqueous cross-metathesis has allowed the first examples of such a reaction on proteins. This led to a new benchmark in substrate complexity for cross-metathesis and expanded the potential of olefin metathesis for other applications in chemical biology. The enhanced reactivity of allyl sulfide, along with earlier reports of a similar effect by allylic hydroxy groups, suggests that allyl chalcogens generally play an important role in modulating the rate of olefin metathesis. In this review, we discuss the effect of allylic chalcogens in olefin metathesis and highlight its most recent applications in synthetic chemistry and protein modifications. PMID:21283554

  18. Interplay of metal-allyl and metal-metal bonding in dimolybdenum allyl complexes

    Energy Technology Data Exchange (ETDEWEB)

    John, Kevin D [Los Alamos National Laboratory; Martin, Richard L [Los Alamos National Laboratory; Obrey, Steven J [Los Alamos National Laboratory; Scott, Brian L [Los Alamos National Laboratory


    Addition of PMe{sub 3} to Mo{sub 2}(allyl){sub 4} afforded Mo{sub 2}(allyl){sub 4}(PMe{sub 3}){sub 2}, in which two of the allyl groups adopt an unprecedented {mu}{sub 2{sup -}}{eta}{sup 1}, {eta}{sup 3} bonding mode; theoretical studies elucidate the role sof the {sigma}- and {pi}-donor ligands in the interplay of metal-allyl and metal-metal bonding.

  19. Synthesis of Propargyl-Terminated Heterobifunctional Poly(ethylene glycol

    Directory of Open Access Journals (Sweden)

    Wen Zhong


    Full Text Available Novel propargyl-ended heterobifunctional poly(ethylene glycol (PEG derivatives with hydroxyl, carboxyl, mercapto or hydrazide end groups were synthesized with simplicity yet high efficiency. PEG (Mw = 3500 Da with an α-hydroxyl group and an ω-carboxyl was used as the starting polymer. The carboxyl group of the bifunctional PEG was modified into a propargyl, then carboxyl, mercapto or hydrazide groups were introduced to the other end of the bifunctional PEG by modifying the bifunctional PEG’s hydroxyl group with succinic anhydride, cysteamide or tert-butyl carbazate, respectively. This method can be useful to the development of PEG-based bioconjugates for a variety of biomedical applications.

  20. HBF4-Catalysed Nucleophilic Substitutions of Propargylic Alcohols (United States)

    Barreiro, Elena; Sanz-Vidal, Alvaro; Tan, Eric; Lau, Shing-Hing; Sheppard, Tom D; Díez-González, Silvia


    The activity of HBF4 (aqueous solution) as a catalyst in propargylation reactions is presented. Diverse types of nucleophiles were employed in order to form new C–O, C–N and C–C bonds in technical acetone and in air. Good to excellent yields and good chemoselectivities were obtained using low acid loading (typically 1 mol-%) under simple reaction conditions. PMID:26693210

  1. Highly enantio- and diastereoselective allylic alkylation of Morita-Baylis-Hillman carbonates with allyl ketones

    KAUST Repository

    Tong, Guanghu


    The asymmetric allylic alkylation of Morita-Baylis-Hillman (MBH) carbonates with allyl ketones has been developed. The α-regioselective alkylation adducts, containing a hexa-1,5-diene framework with important synthetic value, were achieved in up to 83% yield, >99% ee, and 50:1 dr by using a commercially available Cinchona alkaloid as the catalyst. From the allylic alkylation adduct, a cyclohexene bearing two adjacent chiral centers was readily prepared. © 2013 American Chemical Society.

  2. Regio- and Stereospecific Formation of Protected Allylic Alcohols via Zirconium-Mediated SN2' Substitution of Allylic Chlorides


    Fox, Richard J; Lalic, Gojko; Bergman, Robert G.


    A new, highly regio- and stereospecific SN2' substitution reaction between a zirconium oxo complex and allylic chloride has been achieved. The resulting allylic alcohol or TBS-protected allylic ether products were isolated in good to excellent yields with a wide range of E-allylic chlorides. A mechanism for the SN2' allylic substitution consistent with kinetic, stereochemical and secondary isotope effect studies was proposed.

  3. [bmim][Br] as a solvent and activator for the Ga-mediated Barbier allylation: direct formation of an N-heterocyclic carbene from Ga metal. (United States)

    Goswami, Dibakar; Chattopadhyay, Angshuman; Sharma, Anubha; Chattopadhyay, Subrata


    The room-temperature ionic liquid (RTIL) [bmim][Br] has been found to be an excellent green and inexpensive medium for the Ga-mediated allylation of aromatic and aliphatic aldehydes and ketones. The RTIL activated the metal via formation of a Ga-N-heterocyclic carbene complex that assisted in the completion of the reaction at ambient temperature with only 0.5 equiv of Ga and 1.2 equiv of allyl bromide with respect to the carbonyl substrates. The present protocol required a much shorter time than those reported in the literature using other metals and solvents and proceeded with good yields and excellent selectivity.

  4. Compound list: allyl alcohol [Open TG-GATEs

    Lifescience Database Archive (English)

    Full Text Available allyl alcohol AA 00010 ftp:/.../ ...

  5. Synthesis of 3-Allyl-4-phosphachromones by Cyclized Coupling of Ethyl o-Hydroxyphenyl(ethynyl)phosphinate with Allyl Bromide

    Institute of Scientific and Technical Information of China (English)


    3-Allyl-4-phosphachromones as the phosphorus analogues of chromone were firstly prepared in good yields and high regioselectivity by the palladium(Ⅱ)-catalyzed cyclized coupling reaction of ethyl o-hydroxyphenyl(ethynyl)-phosphinate with allyl bromide.

  6. Tether-directed synthesis of highly substituted oxasilacycles via an intramolecular allylation employing allylsilanes

    Directory of Open Access Journals (Sweden)

    Cox Liam R


    Full Text Available Abstract Background Using a silyl tether to unite an aldehyde electrophile and allylsilane nucleophile into a single molecule allows a subsequent Lewis-acid-mediated allylation to proceed in an intramolecular sense and therefore receive all the benefits associated with such processes. However, with the ability to cleave the tether post allylation, a product that is the result of a net intermolecular reaction can be obtained. In the present study, four diastereoisomeric β-silyloxy-α-methyl aldehydes, which contain an allylsilane tethered through the β-carbinol centre, have been prepared, in order to probe how the relative configuration of the two stereogenic centres affects the efficiency and selectivity of the intramolecular allylation. Results Syn-aldehydes, syn-4a and syn-4b, both react poorly, affording all four possible diastereoisomeric oxasilacycle products. In contrast, the anti aldehydes anti-4a and anti-4b react analogously to substrates that lack substitution at the α-site, affording only two of the four possible allylation products. Conclusion The outcome of the reaction with anti-aldehydes is in accord with reaction proceeding through a chair-like transition state (T.S.. In these systems, the sense of 1,3-stereoinduction can be rationalised by the aldehyde electrophile adopting a pseudoaxial orientation, which will minimise dipole-dipole interactions in the T.S. The 1,4-stereoinduction in these substrates is modest and seems to be modulated by the R substituent in the starting material. In the case of the syn-substrates, cyclisation through a chair T.S. is unlikely as this would require the methyl substituent α to the reacting carbonyl group to adopt an unfavourable pseudoaxial position. It is therefore proposed that these substrates react through poorly-defined T.S.s and consequently exhibit essentially no stereoselectivity.

  7. Rh-Catalyzed Chemo- and Enantioselective Hydrogenation of Allylic Hydrazones. (United States)

    Hu, Qiupeng; Hu, Yanhua; Liu, Yang; Zhang, Zhenfeng; Liu, Yangang; Zhang, Wanbin


    A highly efficient P-stereogenic diphosphine-rhodium complex was applied to the chemo- and enantioselective hydrogenation of allylic hydrazones for the synthesis of chiral allylic hydrazines in 89-96 % yields and with 82-99 % ee values. This methodology was successfully applied to the preparation of versatile chiral allylic amine derivatives.

  8. Elementary reaction allyl radical with oxygen

    Institute of Scientific and Technical Information of China (English)

    DONG Feng; KONG Fanao


    The elementary reaction between allyl radical with oxygen molecule wasexperimentally investigated. The allyl radical was produced via laser photolysis of C3H5Br in gaseous phase. Nascent vibrational excited products HCO, CO2, CH3CHO and HCOOH were recorded by the time- resolved Fourier transform infrared spectroscopy. The product channels of C2H5+CO2, CH3CHO+HCO, and HCOOH + C2H3 have been identified. The vibrational populations of product CO2 are obtained by spectral simulation. A mechanism forming a series of three-membered ring-struc- ture intermediates is suggested.

  9. Thermal decomposition of propargyl alcohol: single pulse shock tube experimental and ab initio theoretical study. (United States)

    Sharath, N; Reddy, K P J; Arunan, E


    Thermal decomposition of propargyl alcohol (C3H3OH), a molecule of interest in interstellar chemistry and combustion, was investigated using a single pulse shock tube in the temperature ranging from 953 to 1262 K. The products identified include acetylene, propyne, vinylacetylene, propynal, propenal, and benzene. The experimentally observed overall rate constant for thermal decomposition of propargyl alcohol was found to be k = 10((10.17 ± 0.36)) exp(-(39.70 ± 1.83)/RT) s(-1). Ab initio theoretical calculations were carried out to understand the potential energy surfaces involved in the primary and secondary steps of propargyl alcohol thermal decomposition. Transition state theory was used to predict the rate constants, which were then used and refined in a kinetic simulation of the product profile. The first step in the decomposition is C-O bond dissociation, leading to the formation of two important radicals in combustion, OH and propargyl. This has been used to study the reverse OH + propargyl radical reaction, about which there appears to be no prior work. Depending on the site of attack, this reaction leads to propargyl alcohol or propenal, one of the major products at temperatures below 1200 K. A detailed mechanism has been derived to explain all the observed products.

  10. Validation of protein carbonyl measurement

    DEFF Research Database (Denmark)

    Augustyniak, Edyta; Adam, Aisha; Wojdyla, Katarzyna;


    Protein carbonyls are widely analysed as a measure of protein oxidation. Several different methods exist for their determination. A previous study had described orders of magnitude variance that existed when protein carbonyls were analysed in a single laboratory by ELISA using different commercial...

  11. Validation of protein carbonyl measurement

    DEFF Research Database (Denmark)

    Augustyniak, Edyta; Adam, Aisha; Wojdyla, Katarzyna


    Protein carbonyls are widely analysed as a measure of protein oxidation. Several different methods exist for their determination. A previous study had described orders of magnitude variance that existed when protein carbonyls were analysed in a single laboratory by ELISA using different commercial...... kits. We have further explored the potential causes of variance in carbonyl analysis in a ring study. A soluble protein fraction was prepared from rat liver and exposed to 0, 5 and 15min of UV irradiation. Lyophilised preparations were distributed to six different laboratories that routinely undertook...... protein carbonyl analysis across Europe. ELISA and Western blotting techniques detected an increase in protein carbonyl formation between 0 and 5min of UV irradiation irrespective of method used. After irradiation for 15min, less oxidation was detected by half of the laboratories than after 5min...

  12. Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction

    Directory of Open Access Journals (Sweden)

    Thomas Zeuch


    Full Text Available Photochemically driven reactions involving unsaturated radicals produce a thick global layer of organic haze on Titan, Saturn’s largest moon. The allyl radical self-reaction is an example for this type of chemistry and was examined at room temperature from an experimental and kinetic modelling perspective. The experiments were performed in a static reactor with a volume of 5 L under wall free conditions. The allyl radicals were produced from laser flash photolysis of three different precursors allyl bromide (C3H5Br, allyl chloride (C3H5Cl, and 1,5-hexadiene (CH2CH(CH22CHCH2 at 193 nm. Stable products were identified by their characteristic vibrational modes and quantified using FTIR spectroscopy. In addition to the (re- combination pathway C3H5+C3H5 → C6H10 we found at low pressures around 1 mbar the highest final product yields for allene and propene for the precursor C3H5Br. A kinetic analysis indicates that the end product formation is influenced by specific reaction kinetics of photochemically activated allyl radicals. Above 10 mbar the (re- combination pathway becomes dominant. These findings exemplify the specificities of reaction kinetics involving chemically activated species, which for certain conditions cannot be simply deduced from combustion kinetics or atmospheric chemistry on Earth.


    Directory of Open Access Journals (Sweden)

    Gagik Torosyan


    Full Text Available It has been established the possibility for phenol allylation on natural zeolites and them analogs. Here is demonstrated the synthesis of allyl phenol, which has wide industrial applications. The offered method in comparison with the traditional methods has more advantages – higher selectivity, smaller material and power resources consumption. It has been obtained the mixture of allylating phenols (30% in general with allyl phenyl ether (1 with 80% yields. At 600 K is obtained allylphenyl ether, at 700 K beginning the formation of allyl phenols, which is the result of direct C-allylation of the aromatic ring. It has been investigated the possibility of Claisen rearrangement in the same conditions. All of that are established by gas-liquid chromatography and liquid chromatography data.

  14. Cp*Co(III)-Catalyzed Dehydrative C-H Allylation of 6-Arylpurines and Aromatic Amides Using Allyl Alcohols in Fluorinated Alcohols. (United States)

    Bunno, Youka; Murakami, Nanami; Suzuki, Yudai; Kanai, Motomu; Yoshino, Tatsuhiko; Matsunaga, Shigeki


    Cp*Co(III)-catalyzed C-H allylation of various aromatic C-H bonds using allyl alcohols as allylating reagents is described. Improved reaction conditions using fluorinated alcohol solvents afforded efficient directed C-H allylation of 6-arylpurines, benzamides, and a synthetically useful Weinreb amide with good functional group compatibility.

  15. 49 CFR 173.198 - Nickel carbonyl. (United States)


    ... 49 Transportation 2 2010-10-01 2010-10-01 false Nickel carbonyl. 173.198 Section 173.198... Nickel carbonyl. (a) Nickel carbonyl must be packed in specification steel or nickel cylinders as prescribed for any compressed gas except acetylene. A cylinder used exclusively for nickel carbonyl may...

  16. Rhodium-catalyzed acyloxy migration of propargylic esters in cycloadditions, inspiration from the recent "gold rush". (United States)

    Shu, Xing-Zhong; Shu, Dongxu; Schienebeck, Casi M; Tang, Weiping


    Transition metal-catalyzed acyloxy migration of propargylic esters offers versatile entries to allene and vinyl carbene intermediates for various fascinating subsequent transformations. Most π-acidic metals (e.g. gold and platinum) are capable of facilitating these acyloxy migration events. However, very few of these processes involve redox chemistry, which are well-known for most other transition metals such as rhodium. The coupling of acyloxy migration of propargylic esters with oxidative addition, migratory insertion, and reductive elimination may lead to ample new opportunities for the design of new reactions. This tutorial review summarizes recent developments in Rh-catalyzed 1,3- and 1,2-acyloxy migration of propargylic esters in a number of cycloaddition reactions. Related Au- and Pt-catalyzed cycloadditions involving acyloxy migration are also discussed.

  17. Amination of allylic alcohols in water at room temperature. (United States)

    Nishikata, Takashi; Lipshutz, Bruce H


    The "trick" to carrying out regiocontrolled aminations of allylic alcohols in water as the only medium is use of a nanomicelle's interior as the organic reaction solvent. When HCO(2)Me is present, along with the proper base and source of catalytic Pd, allylic amines are cleanly formed at room temperature.

  18. Allyl borates: a novel class of polyhomologation initiators

    KAUST Repository

    Wang, De


    Allyl borates, a new class of monofunctional polyhomologation initiators, are reported. These monofunctional initiators are less sensitive and more effective towards polymethylene-based architectures. As an example, the synthesis of α-vinyl-ω-hydroxypolymethylenes is given. By designing/synthesizing different allylic borate initiators, and using 1H and 11B NMR spectroscopy, the initiation mechanism was elucidated.

  19. Radiation and thermal polymerization of allyl(p-allylcarbonate) benzoate

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-V, D., E-mail: dlopez@siu.buap.m [Facultad de Ciencias Quimicas, Benemerita Universidad Autonoma de Puebla, Antiguo Edificio de la Fac. de Cs., Quimica. Av. San Claudio y Boulevard de la 14 sur, Col. San Manuel, Puebla, Pue., CP 72500 (Mexico); Herrera-G, A.M., E-mail: mherrera@uaeh.reduaeh.m [Centro de Inv. en Materiales y Metalurgia, UAEH. Km 4.5, C.U., CP 42184, Pachuca de S. Hidalgo (Mexico); Castillo-Rojas, S., E-mail: castillo@nucleares.unam.m [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, 04510 DF (Mexico)


    Bulk polymerization of novel allyl(p-allylcarbonate) benzoate was investigated using different sources of energy, such as gamma rays, ultraviolet rays as well as thermal polymerization. The poly(allyl(p-allylcarbonate) benzoate) obtained is a cross-linking, transparent, thermoset polycarbonate. Compositions of the monomer and the polycarbonate were analyzed by infrared spectroscopy, elemental analysis, and {sup 1}H NMR spectroscopy.

  20. Convenient synthesis of a propargylated cyclic (3'-5') diguanylic acid and its "click" conjugation to a biotinylated azide. (United States)

    Grajkowski, Andrzej; Cieślak, Jacek; Gapeev, Alexei; Schindler, Christian; Beaucage, Serge L


    The ribonucleoside building block, N²-isobutyryl-2'-O-propargyl-3'-O-levulinyl guanosine, was prepared from commercial N²-isobutyryl-5'-O-(4,4'-dimethoxytrityl)-2'-O-propargyl guanosine in a yield of 91%. The propargylated guanylyl(3'-5')guanosine phosphotriester was synthesized from the reaction of N²-isobutyryl-2'-O-propargyl-3'-O-levulinyl guanosine with N²-isobutyryl-5'-O-(4,4'-dimethoxytrityl)-2'-O-tert-butyldimethylsilyl-3'-O-[(2-cyanoethyl)-N,N-diisopropylaminophosphinyl] guanosine and isolated in a yield of 88% after P(III) oxidation, 3'-/5'-deprotection, and purification. The propargylated guanylyl(3'-5')guanosine phosphotriester was phosphitylated using 2-cyanoethyl tetraisopropylphosphordiamidite and 1H-tetrazole and was followed by an in situ intramolecular cyclization to give a propargylated c-di-GMP triester, which was isolated in a yield of 40% after P(III) oxidation and purification. Complete N-deacylation of the guanine bases and removal of the 2-cyanoethyl phosphate protecting groups from the propargylated c-di-GMP triester were performed by treatment with aqueous ammonia at ambient temperature. The final 2'-desilylation reaction was effected by exposure to triethylammonium trihydrofluoride affording the desired propargylated c-di-GMP diester, the purity of which exceeded 95%. Biotinylation of the propargylated c-di-GMP diester was easily accomplished through its cycloaddition reaction with a biotinylated azide derivative under click conditions to produce the biotinylated c-di-GMP conjugate of interest in an isolated yield of 62%.

  1. Synthesis of α-Quaternized 2,4-Cyclohexadienones from Propargyl Vinyl Ethers. (United States)

    Tejedor, David; Delgado-Hernández, Samuel; Ingold, Mariana; García-Tellado, Fernando


    A microwave-assisted and base-catalyzed domino manifold to construct 2,4-cyclohexadienone derivatives has been implemented. The domino manifold uses easily accessible tertiary propargyl vinyl ethers bearing a methine group at the homopropargylic position and imidazole as the catalyst to deliver 2,4-cyclohexadienones featuring a key formyl group and a quaternized carbon atom in good yields.

  2. One-pot synthesis of arene-fused 2-acylcyclohexenones from propargylic carboxylates

    Institute of Scientific and Technical Information of China (English)


    From readily available propargylic carboxylates, two sequential transformations―gold-catalyzed tandem reactions and Sc(OTf)3-catalyzed cyclization―in a one-pot process led to the formation of 2-acylcyclohexenones with an electron-rich arene ring fused at the 4,5-positions.

  3. Facile synthesis of bromoallenes via N-bromosuccinimide/CH3SCH3 for the bromination of propargyl alcohols

    Institute of Scientific and Technical Information of China (English)

    Wen Feng Jiang; Xue Song Liu; Xin Du; Jian Wei Wei; Chun Yu Bao


    A novel and convenient way has been developed for the preparation of bromoallenes from propargyl alcohols by the reagent combination of N-bromosuccinimide and dimethyl sulfide.Bromoallenes with high regioselectivity were obtained in a convenient method.

  4. Rhodium-Catalyzed Acyloxy Migration of Propargylic Esters in Cycloadditions, Inspiration from Recent “Gold Rush”


    Shu, Xing-Zhong; Shu, Dongxu; Schienebeck, Casi M.; Tang, Weiping


    Transition metal-catalyzed acyloxy migration of propargylic esters offers versatile entries to allene and vinyl carbene intermediates for various fascinating subsequent transformations. Most π-acidic metals (e.g. gold and platinum) are capable of facilitating these acyloxy migration events. However, very few of these processes involve redox chemistry, which are well-known for most other transition metals such as rhodium. The coupling of acyloxy migration of propargylic esters with oxidative a...

  5. Zinc Mediated Tandem Fragmentation-Allylation of Methyl 5-Iodopentofuranosides

    DEFF Research Database (Denmark)

    Hyldtoft, Lene; Madsen, Robert


    In the presence of zinc and allyl bromide methyl 5-iodopentofuranosides undergo a tandem fragmentation alkylation to give functionalized dienes. These can undergo ring-closing olefin metathesis to produce cyclohexenes which on dihydroxylation give quercitols....

  6. Chiral allylic and allenic metal reagents for organic synthesis. (United States)

    Marshall, James A


    This account traces the evolution of our work on the synthesis of chiral allylic and allenic organometal compounds of tin, silicon, zinc, and indium and their application to natural product synthesis over the past quarter century.

  7. Corrosion Inhibition Propargyl Alcohol on Low Alloy Cr Steel in 0.5 M H2SO4 in the Absence and Presence of Potassium Iodide


    Baghaei Ravari, Fatemeh; Heydari, Mahdi; Dadgarineghad, Athareh


    The corrosion and inhibition behaviors of low alloy Cr steel in sulfuric acid in the presence of propargyl alcohol (PA) and potassium iodide (KI) have been studied using Electrochemical Impedance Spectroscopy (EIS) and Tafel polarization method. It was found that the inhibition efficiency increased with PA concentration. The addition of potassium iodide to propargyl alcohol in solution increased the inhibition efficiency of propargyl alcohol. A synergistic effect was observed between KI and P...

  8. Corrosion Inhibition Propargyl Alcohol on Low Alloy Cr Steel in 0.5 M H2SO4 in the Absence and Presence of Potassium Iodide


    Baghaei Ravari, Fatemeh; Heydari, Mahdi; Dadgarineghad, Athareh


    The corrosion and inhibition behaviors of low alloy Cr steel in sulfuric acid in the presence of propargyl alcohol (PA) and potassium iodide (KI) have been studied using Electrochemical Impedance Spectroscopy (EIS) and Tafel polarization method. It was found that the inhibition efficiency increased with PA concentration. The addition of potassium iodide to propargyl alcohol in solution increased the inhibition efficiency of propargyl alcohol. A synergistic effect was observed between KI and P...

  9. Copper-catalyzed regioselective allylic substitution reactions with indium organometallics. (United States)

    Rodríguez, David; Sestelo, José Pérez; Sarandeses, Luis A


    The first nucleophilic allylic substitution reactions of triorganoindium compounds with allylic halides and phosphates are reported. The reactions of trialkyl- and triarylindium reagents with cinnamyl and geranyl halides and phosphates, with the aid of copper catalysis [Cu(OTf)(2)/P(OEt)(3)], are described. In general, the reaction proceeds efficiently to give good yields and regioselectively to afford the S(N)2' product.

  10. Metal-catalyzed double migratory cascade reactions of propargylic esters and phosphates. (United States)

    Kazem Shiroodi, Roohollah; Gevorgyan, Vladimir


    Propargylic esters and phosphates are easily accessible substrates, which exhibit rich and tunable reactivities in the presence of transition metal catalysts. π-Acidic metals, mostly gold and platinum salts, activate these substrates for an initial 1,2- or 1,3-acyloxy and phosphatyloxy migration process to form reactive intermediates. These intermediates are able to undergo further cascade reactions leading to a variety of diverse structures. This tutorial review systematically introduces the double migratory reactions of propargylic esters and phosphates as a novel synthetic method, in which further cascade reaction of the reactive intermediate is accompanied by a second migration of a different group, thus offering a rapid route to a wide range of functionalized products. The serendipitous observations, as well as designed approaches involving the double migratory cascade reactions, will be discussed with emphasis placed on the mechanistic aspects and the synthetic utilities of the obtained products.

  11. Aza Cope Rearrangement of Propargyl Enammonium Cations Catalyzed By a Self-Assembled `Nanozyme

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, Courntey J.; Fiedler, Dorothea; Bergman, Robert G.; Raymond, Kenneth N.


    The tetrahedral [Ga{sub 4}L{sub 6}]{sup 12-} assembly (L = N,N-bis(2,3-dihydroxybenzoyl)-1,5-diaminonaphthalene) encapsulates a variety of cations, including propargyl enammonium cations capable of undergoing the aza Cope rearrangement. For propargyl enammonium substrates that are encapsulated in the [Ga{sub 4}L{sub 6}]{sup 12-} assembly, rate accelerations of up to 184 are observed when compared to the background reaction. After rearrangement, the product iminium ion is released into solution and hydrolyzed allowing for catalytic turnover. The activation parameters for the catalyzed and uncatalyzed reaction were determined, revealing that a lowered entropy of activation is responsible for the observed rate enhancements. The catalyzed reaction exhibits saturation kinetics; the rate data obey the Michaelis-Menten model of enzyme kinetics, and competitive inhibition using a non-reactive guest has been demonstrated.

  12. Molecular Mechanics and Quantum Chemistry Based Study of Nickel-N-Allyl Urea and N-Allyl Thiourea Complexes

    Directory of Open Access Journals (Sweden)

    P. D. Sharma


    Full Text Available Eigenvalue, eigenvector and overlap matrix of nickel halide complex of N-allyl urea and N-allyl thiourea have been evaluated. Our results indicate that ligand field parameters (Dq, B’ and β evaluated earlier by electronic spectra are very close to values evaluated with the help of eigenvalues and eigenvectors. Eigenvector analysis and population analysis shows that in bonding 4s, 4p, and 3dx2-y2, 3dyz orbitals of nickel are involved but the coefficient values differ in different complexes. Out of 4px, 4py, 4pz the involvement of either 4pz or 4py, is noticeable. The theoretically evaluated positions of infrared bands indicate that N-allyl urea is coordinated to nickel through its oxygen and N-allyl thiourea is coordinated to nickel through its sulphur which is in conformity with the experimental results.

  13. Rotational spectra of propargyl alcohol dimer: A dimer bound with three different types of hydrogen bonds

    Energy Technology Data Exchange (ETDEWEB)

    Mani, Devendra; Arunan, E., E-mail: [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012 (India)


    Pure rotational spectra of the propargyl alcohol dimer and its three deuterium isotopologues have been observed in the 4 to 13 GHz range using a pulsed-nozzle Fourier transform microwave spectrometer. For the parent dimer, a total of 51 transitions could be observed and fitted within experimental uncertainty. For two mono-substituted and one bi-substituted deuterium isotopologues, a total of 14, 17, and 19 transitions were observed, respectively. The observed rotational constants for the parent dimer [A = 2321.8335(4) MHz, B = 1150.4774(2) MHz, and C = 1124.8898(2) MHz] are close to those of the most stable structure predicted by ab initio calculations. Spectra of the three deuterated isotopologues and Kraitchman analysis positively confirm this structure. Geometrical parameters and “Atoms in Molecules” analysis on the observed structure reveal that the two propargyl alcohol units in the dimer are bound by three different types of hydrogen bonds: O–H⋯O, O–H⋯π, and C–H⋯π. To the best of our knowledge, propargyl alcohol seems to be the smallest molecule forming a homodimer with three different points of contact.

  14. Kinetics of the Double Carbonylation of Benzylchloride

    Institute of Scientific and Technical Information of China (English)


    It is a multi-phase-catalyzed reaction to produce calcium phenylpyruvate by double carbonylation of benzylchloride. Based on the analysis of the reaction mechanism, a kinetic model of the carbonylation reaction was obtained. The model was verified through experiments in which the diffusion effect was neglected with the appropriate operation manner. But it is inevitable that the carbonylation process is controlled by diffusion as the autoclave scaling up.

  15. Structurally defined allyl compounds of main group metals: coordination and reactivity. (United States)

    Lichtenberg, Crispin; Okuda, Jun


    Organometallic allyl compounds are important as allylation reagents in organic synthesis, as polymerization catalysts, and as volatile metal precursors in material science. Whereas the allyl chemistry of synthetically relevant transition metals such as palladium and of the lanthanoids is well-established, that of main group metals has been lagging behind. Recent progress on allyl complexes of Groups 1, 2, and 12-16 now provides a more complete picture. This is based on a fundamental understanding of metal-allyl bonding interactions in solution and in the solid state. Furthermore, reactivity trends have been rationalized and new types of allyl-specific reactivity patterns have been uncovered. Key features include 1) the exploitation of the different types of metal-allyl bonding (highly ionic to predominantly covalent), 2) the use of synergistic effects in heterobimetallic compounds, and 3) the adjustment of Lewis acidity by variation of the charge of allyl compounds.

  16. Scalable and sustainable electrochemical allylic C-H oxidation (United States)

    Horn, Evan J.; Rosen, Brandon R.; Chen, Yong; Tang, Jiaze; Chen, Ke; Eastgate, Martin D.; Baran, Phil S.


    New methods and strategies for the direct functionalization of C-H bonds are beginning to reshape the field of retrosynthetic analysis, affecting the synthesis of natural products, medicines and materials. The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C-H functionalization, owing to the utility of enones and allylic alcohols as versatile intermediates, and their prevalence in natural and unnatural materials. Allylic oxidations have featured in hundreds of syntheses, including some natural product syntheses regarded as “classics”. Despite many attempts to improve the efficiency and practicality of this transformation, the majority of conditions still use highly toxic reagents (based around toxic elements such as chromium or selenium) or expensive catalysts (such as palladium or rhodium). These requirements are problematic in industrial settings; currently, no scalable and sustainable solution to allylic oxidation exists. This oxidation strategy is therefore rarely used for large-scale synthetic applications, limiting the adoption of this retrosynthetic strategy by industrial scientists. Here we describe an electrochemical C-H oxidation strategy that exhibits broad substrate scope, operational simplicity and high chemoselectivity. It uses inexpensive and readily available materials, and represents a scalable allylic C-H oxidation (demonstrated on 100 grams), enabling the adoption of this C-H oxidation strategy in large-scale industrial settings without substantial environmental impact.

  17. Study of decomposing carbonyl slag

    Institute of Scientific and Technical Information of China (English)

    CHEN Ai-liang; SUN Pei-mei; ZHAO Zhong-wei; LI Hong-gui; CHEN Xing-yu


    A new technology was put forward to deal with the carbonyl slag at low acidity and low oxygen pressure in the kettle.With the orthogonal experiments for analyzing the sequence of four factors and some single factor experiments for the best conditions. The best conditions are used for extracting nickel, cobalt and copper and enriching precious metals: the cupric ion concentration is 5 g/L; and pH=6; the sulfur coefficient is 1.4; the oxygen pressure is 0.08 MPa; the time bubbling oxygen is 20 min;the ratio of liquid to solid is 8:1; the leaching time is 2 h; the heating time is 2.5 h. The leaching rates of nickel and cobalt are more than 98% and that of copper is above 97%. Nickel and cobalt can be separated efficiently from copper and precious metals from the carbonyl slag. Moreover, its leaching liquor has less copper. Nickel and cobalt can be reclaimed only once. During the whole process,the leaching rates of Au and Ag are more than 99.9%, while other precious metals are still in the residue without any loss.

  18. Catalytic Enantioselective Allylic Amination of Olefins for the Synthesis of ent-Sitagliptin. (United States)

    Bao, Hongli; Bayeh, Liela; Tambar, Uttam K


    The presence of nitrogen atoms in most chiral pharmaceutical drugs has motivated the development of numerous strategies for the synthesis of enantioenriched amines. Current methods are based on the multi-step transformation of pre-functionalized allylic electrophiles into chiral allylic amines. The enantioselective allylic amination of unactivated olefins represents a more direct and attractive strategy. We report the enantioselective synthesis of ent-sitagliptin via an allylic amination of an unactivated terminal olefin.

  19. Redox-Neutral Rh(III)-Catalyzed Olefination of Carboxamides with Trifluoromethyl Allylic Carbonate. (United States)

    Park, Jihye; Han, Sangil; Jeon, Mijin; Mishra, Neeraj Kumar; Lee, Seok-Yong; Lee, Jong Suk; Kwak, Jong Hwan; Um, Sung Hee; Kim, In Su


    The rhodium(III)-catalyzed olefination of various carboxamides with α-CF3-substituted allylic carbonate is described. This reaction provides direct access to linear CF3-allyl frameworks with complete trans-selectivity. In particular, a rhodium catalyst provided Heck-type γ-CF3-allylation products via the β-O-elimination of rhodacycle intermediate and subsequent olefin migration process.

  20. A convenient procedure for the synthesis of allyl and benzyl ethers from alcohols and phenols

    Indian Academy of Sciences (India)

    H Surya Prakash Rao; S P Senthilkumar


    Allyl and benzyl ethers of alcohols can be prepared conveniently and in high yield with allyl and benzyl bromide in the presence of solid potassium hydroxide without use of any solvent. Phenols can be converted to allyl ethers but are inert to benzylation under above conditions.

  1. 40 CFR 721.7000 - Polymer of disodium maleate, allyl ether, and ethylene oxide. (United States)


    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymer of disodium maleate, allyl... New Uses for Specific Chemical Substances § 721.7000 Polymer of disodium maleate, allyl ether, and... substance identified generically as a polymer of disodium maleate, allyl ether, and ethylene oxide...


    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhenfeng; HU Xingzhou; YAN Qing


    Photoinduced grafting of acrylic and allyl monomers on polyethylene surface was generally studied by using benzophenone (BP) as a photoinitiator. The grafting process was carried out either in vapor-phase or in solution of the monomers. In the vapor-phase reaction with a filter used to cut off the short wavelength UV light, allyl amine is the most reactive of the four monomers used and acrylic amide is comparatively more reactive than acrylic acid and allyl alcohol. Acetone, as a solvent and carrier for initiator and monomers, however, shows its reactivity to participate the reaction. The solution grafting with a filter is much faster than the corresponding vapor-phase reaction, and a fully covered surface by the grafted polymer can be achieved in this way.

  3. Microwave-Assisted Organocatalyzed Rearrangement of Propargyl Vinyl Ethers to Salicylaldehyde Derivatives: An Experimental and Theoretical Study. (United States)

    Tejedor, David; Cotos, Leandro; Márquez-Arce, Daniel; Odriozola-Gimeno, Mikel; Torrent-Sucarrat, Miquel; Cossío, Fernando P; García-Tellado, Fernando


    The microwave-assisted imidazole-catalyzed transformation of propargyl vinyl ethers (PVEs) into multisubstituted salicylaldehydes is described. The reaction is instrumentally simple, scalable, and tolerates a diverse degree of substitution at the propargylic position of the starting PVE. The generated salicylaldehyde motifs incorporate a broad range of topologies, spanning from simple aromatic monocycles to complex fused polycyclic systems. The reaction is highly regioselective and takes place under symmetry-breaking conditions. The preparative power of this reaction was demonstrated in the first total synthesis of morintrifolin B, a benzophenone metabolite isolated from the small tree Morinda citrifolia L. A DFT study of the reaction was performed with full agreement between calculated values and experimental results. The theoretically calculated values support a domino mechanism comprising a propargyl Claisen rearrangement, a [1,3]-H shift, a [1,7]-H shift (enolization), a 6π electrocyclization, and an aromatization reaction.

  4. Direct activation of allylic alcohols in palladium catalyzed coupling reactions


    Gümrükçü, Y.


    The direct use of allylic alcohols in substitution reactions without pre-activation of the hydroxyl-group into a better leaving group or the use of additional stoichiometric in situ activators remains challenging due to the poor leaving group ability of the hydroxyl-group. Hence, it is important to develop new methods to activate (bio-mass derived) allyl-alcohols, which allow ‘green’ chemical processes for a broad substrate range. This may have a considerable impact on the methodology for fin...

  5. Surface decorated platinum carbonyl clusters (United States)

    Ciabatti, Iacopo; Femoni, Cristina; Iapalucci, Maria Carmela; Longoni, Giuliano; Zacchini, Stefano; Zarra, Salvatore


    Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters.Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters. CCDC 867747 and 867748. For crystallographic data in CIF or other electronic format see DOI: 10.1039/c2nr30400g

  6. Palladium-catalyzed asymmetric allylic substitution of 2-arylcyclohexenol derivatives: asymmetric total syntheses of (+)-crinamine, (-)-haemanthidine, and (+)-pretazettine. (United States)

    Nishimata, Toyoki; Sato, Yoshihiro; Mori, Miwako


    Much interest has been shown in Amaryllidaceae alkaloids as synthetic targets due to their wide range of biological activities. Over 100 alkaloids have been isolated from members of the Amaryllidaceae family; most of them can be classified into eight skeletally homogeneous groups. We have succeeded in the first asymmetric total syntheses of the crinane-type alkaloids (+)-crinamine (1), (-)-haemanthidine (2), and (+)-pretazettine (3). The starting cyclohexenylamine 14 was obtained from allyl phosphonate 11c by palladium-catalyzed asymmetric amination in 82% yield and with 74% ee. The product was recrystallized from MeOH. Interestingly, (-)-14 with 99% ee was obtained from the mother liquor (74% recovery). Intramolecular carbonyl-ene reaction of (-)-10 proceeds in a highly stereoselective manner to give hexahydroindole derivative 9 as the sole product. In the Lewis-acid-catalyzed carbonyl-ene reaction, an interesting rearrangement product, 20, was isolated in high yield. From 9, (+)-crinamine was synthesized. Thus, the asymmetric total synthesis of (+)-crinamine was achieved in 10 steps from 11c, and the overall yield is 19%. The total synthesis of (-)-haemanthidine was also achieved from 9 by a short sequence of steps.

  7. Direct activation of allylic alcohols in palladium catalyzed coupling reactions

    NARCIS (Netherlands)

    Gümrükçü, Y.


    The direct use of allylic alcohols in substitution reactions without pre-activation of the hydroxyl-group into a better leaving group or the use of additional stoichiometric in situ activators remains challenging due to the poor leaving group ability of the hydroxyl-group. Hence, it is important to

  8. Sulfonium-based Ionic Liquids Incorporating the Allyl Functionality

    Directory of Open Access Journals (Sweden)

    Paul J. Dyson


    Full Text Available A series of sulfonium halides bearing allyl groups have been prepared andcharacterized. Anion metathesis with Li[Tf2N] and Ag[N(CN2] resulted in sulfonium-basedionic liquids which exhibit low viscosities at room temperature. The solid state structure ofone of the halide salts was determined by single crystal X-ray diffraction.

  9. Single pulse shock tube study of allyl radical recombination. (United States)

    Fridlyand, Aleksandr; Lynch, Patrick T; Tranter, Robert S; Brezinsky, Kenneth


    The recombination and disproportionation of allyl radicals has been studied in a single pulse shock tube with gas chromatographic measurements at 1-10 bar, 650-1300 K, and 1.4-2 ms reaction times. 1,5-Hexadiene and allyl iodide were used as precursors. Simulation of the results using derived rate expressions from a complementary diaphragmless shock tube/laser schlieren densitometry study provided excellent agreement with precursor consumption and formation of all major stable intermediates. No significant pressure dependence was observed at the present conditions. It was found that under the conditions of these experiments, reactions of allyl radicals in the cooling wave had to be accounted for to accurately simulate the experimental results, and this unusual situation is discussed. In the allyl iodide experiments, higher amounts of allene, propene, and benzene were found at lower temperatures than expected. Possible mechanisms are discussed and suggest that iodine containing species are responsible for the low temperature formation of allene, propene, and benzene.

  10. Electrochemical Allylic Oxidation of Olefins: Sustainable and Safe. (United States)

    Waldvogel, Siegfried R; Selt, Maximilian


    The power you're supplying: With the application of an optimized electrochemical approach, the allylic oxidation of olefins, which is an important C-H activation process that provides access to enones, becomes a sustainable, versatile, and potent key reaction for organic synthesis.

  11. 1-Allyl-5-chloroindoline-2,3-dione

    Directory of Open Access Journals (Sweden)

    Zineb Tribak


    Full Text Available In the title compound, C11H8ClNO2, the allyl side chain is almost perpendicular to the 5-chloroindoline-2,3-dione ring system, with a dihedral angle of 88.0 (3°. In the crystal, C—H...O interactions link the molecules into layers lying parallel to the bc plane.

  12. Convenient Synthesis of a Propargylated Cyclic (3′-5′) Diguanylic Acid and its “Click” Conjugation to a Biotinylated Azide (United States)

    Grajkowski, Andrzej; Cieślak, Jacek; Gapeev, Alexei; Schindler, Christian; Beaucage, Serge L.


    The ribonucleoside building block, N2-isobutyryl-2′-O-propargyl-3′-O-levulinyl guanosine (Scheme 1), was prepared from commercial N2-isobutyryl-5′-O-(4,4′-dimethoxytrityl)-2′-O-propargyl guanosine in a yield of 91%. The propargylated guanylyl(3′-5′)guanosine phosphotriester shown in Scheme 2 was synthesized from the reaction of N2-isobutyryl-2′-O-propargyl-3′-O-levulinyl guanosine with N2-isobutyryl-5′-O-(4,4′-dimethoxytrityl)-2′-O-tert-butyldimethylsilyl-3′-O-[(2-cyanoethyl)-N,N-diisopropylaminophosphinyl] guanosine and isolated in a yield of 88% after P(III) oxidation, 3′-/5′-deprotection and purification. The propargylated guanylyl(3′-5′)guanosine phosphotriester was phosphitylated using 2-cyanoethyl tetraisopropylphosphordiamidite and 1H-tetrazole and was followed by an in situ intramolecular cyclization to give a propargylated c-di-GMP triester (Scheme 3), which was isolated in a yield of 40% after P(III) oxidation and purification. Complete N-deacylation of the guanine bases and removal of the 2-cyanoethyl phosphate protecting groups from the propargylated c-di-GMP triester were performed by treatment with aqueous ammonia at ambient temperature. The final 2′-desilylation reaction was effected by exposure to triethylammonium trihydrofluoride to give the desired propargylated c-di-GMP diester, the purity of which exceeded 95% (Figure 2B). Biotinylation of the propargylated c-di-GMP diester was easily accomplished through its cycloaddition reaction with a biotinylated azide derivative (Scheme 4) under click conditions to produce the biotinylated c-di-GMP conjugate of interest in an isolated yield of 62%. PMID:20942415

  13. Efficient synthesis of eight-membered nitrogen heterocycles from o-propargylic oximes by rhodium-catalyzed cascade reactions. (United States)

    Nakamura, Itaru; Sato, Yoshinori; Takeda, Keisuke; Terada, Masahiro


    Azocine derivatives were successfully synthesized from O-propargylic oximes by means of a Rh-catalyzed 2,3-rearrangement/heterocyclization cascade reaction. Moreover, the chirality of the substrate was maintained throughout the cascade process to afford the corresponding optically active azocines.

  14. Rhodium(II)-Alkynyl Carbenoids Insertion into Si-H bonds: An Entry to Propargylic Geminal Bis(silanes). (United States)

    Courant, Thibaut; Kumar, Rahul; Turcaud, Serge; Micouin, Laurent


    α-Alkynyl-α'-trimethylsilylhydrazones are used as novel Rh(II)-carbenoids precursors. These new carbenoids have shown very good reactivity in Si-H insertion reactions, leading to original propargylic geminal-bis(silanes) in a two-step sequential process.

  15. Isobolographic Analysis for Additive, Synergism and Antagonism Effects in Binary Mixture of Mesosulfuron + Iodosulfuron and Clodinafop-Propargyl

    Directory of Open Access Journals (Sweden)

    A. A Chitband


    Full Text Available The reduction of herbicide applications is a main research priority in recent years for herbicide reducing the risk of side-effects and costs from herbicides. Therefore To predicting additive, synergism or antagonism effects mesosulfuron + iodosulfuron and clodinafop-propargyl two herbicides mixture on wild oat with isobole curvatures, greenhouse experimental in completely randomized design with 36 treatments (in dose-response arrangements and four replicates for each experiment treatments were conducted at Ferdowsi University of Mashhad. Treatments included mesosulfuron + iodosulfuron alone at doses of 0 , 2.4, 6, 12, 18 and 24 g ai ha-1, clodinafop alone at doses of 0, 6.4, 16, 32, 48 and 64 g ai ha-1 and six mixtures ratio of doses of two herbicides above mentioned as 100:0%,75:25%, 50:50%, 25:75% , 10:90% and 0:100%. The results showed mesosulfuron + iodosulfuron and clodinafop-propargyl at high dose rates showed complete control of wild oat. In addition Concentration Addition (CA model describe Fitted the data better than Hewlett and Voelund models. On the other hand, herbicides combination with each other showed additive effects on wild oat control, As by increasing the clodinafop-propargyl ratio in mixtures (90% clodinafop-propargyl + 10% mesosulfuron + iodosulfuron increased wild oat control compared with other mixing ratios remarkably.

  16. Trifluoromethylation of Carbonyl Compounds with Sodium Trifluoroacetate

    Institute of Scientific and Technical Information of China (English)


    In the presence of copper (Ⅰ) halide as catalyst, a variety of carbonyl compounds could be trifluoromethylated with sodium trifluoroacetate to give the corresponding alcohols in moderate to high yields.

  17. Biotinylation of a propargylated cyclic (3'-5') diguanylic acid and of its mono-6-thioated analog under "click" conditions. (United States)

    Grajkowski, Andrzej; Cieślak, Jacek; Schindler, Christian; Beaucage, Serge L


    Commercial N(2)-isobutyryl-5'-O-(4,4'-dimethoxytrityl)-2'-O-(propargyl)guanosine is converted to its 3'-O-levulinyl ester in a yield of 91%. The reaction of commercial N(2)-isobutyryl-5'-O-(4,4'-dimethoxytrityl)-2'-O-tert-butyldimethylsilyl-3'-O-[(2-cyanoethyl)-N,N-diisopropylaminophosphinyl]guanosine with N(2)-isobutyryl-2'-O-propargyl-3'-O-(levulinyl)guanosine provides, after P(III) oxidation, 3'-/5'-deprotection, and purification, the 2'-O-propargylated guanylyl(3'-5')guanosine 2-cyanoethyl phosphate triester in a yield of 88%. Phosphitylation of this dinucleoside phosphate triester with 2-cyanoethyl tetraisopropylphosphordiamidite and 1H-tetrazole, followed by an in situ intramolecular cyclization, gives the propargylated cyclic dinucleoside phosphate triester, which is isolated in a yield of 40% after P(III) oxidation and purification. Complete removal of the nucleobases, phosphates, and 2'-O-tert-butyldimethylsilyl protecting groups leads to the desired propargylated c-di-GMP diester. Cycloaddition of a biotinylated azide with the propargylated c-di-GMP diester under click conditions provides the biotinylated c-di-GMP conjugate in an isolated yield of 62%. Replacement of the 6-oxo function of N(2)-isobutyryl-5'-O-(4,4'-dimethoxytrityl)-3'-O-levulinyl-2'-O-(propargyl)guanosine with a 2-cyanoethylthio group is effected by treatment with 2,4,6-triisopropybenzenesulfonyl chloride and triethylamine to give a 6-(2,4,6-triisopropylbenzenesulfonic acid) ester intermediate. Reaction of this key intermediate with 3-mercaptoproprionitrile and triethylamine, followed by 5'-dedimethoxytritylation, affords the 6-(2-cyanoethylthio)guanosine derivative in a yield of 70%. The 5'-hydroxy function of this derivative is reacted with commercial N(2)-isobutyryl-5'-O-(4,4'-dimethoxytrityl)-2'-O-tert-butyldimethylsilyl-3'-O-[(2-cyanoethyl)-N,N-diisopropylaminophosphinyl]guanosine. The reaction product is then converted to the mono-6-thioated c-di- GMP biotinylated conjugate under

  18. Ab Initio MO Studies on the Reaction Mechanism for Carbonyl Insertion Catalyzed by Carbonyl Cobalt Complex

    Institute of Scientific and Technical Information of China (English)


    Ab initio method, under the effective core potential(ECP) approximation at HF/LANL2DZ level, has been employed to study the reaction mechanism of the carbonyl insertion of olefin hydroformylation catalyzed by a carbonyl cobalt HCo(CO)3. The two reaction paths have been discussed. The calculated potential energy barriers for the carbonyl migration and the ethyl group migration are 105.0 kJ/mol and 39.17 kJ/mol, respectively. The results indicate that the reaction path via ethyl migration is more energetically favorable than that via carbonyl insertion.

  19. Gold-catalyzed reactions of propargylic esters with vinylazides for the synthesis of Z- or E-configured buta-1,3-dien-2-yl esters. (United States)

    Wagh, Sachin Bhausaheb; Liu, Rai-Shung


    Gold-catalyzed synthesis of buta-1,3-dien-2-yl esters by the reaction of propargyl esters with vinylazides is described; the reaction mechanism is postulated to involve a vinyl attack of vinylazides at alkenyl gold carbenes.


    Kennedy, J.


    An ion exchange resin having a relatively high adsorption capacity tor uranyl ion as compared with many common cations is reported. The resin comprises an alphyl-allyl hydrogen phosphate polymer, the alphyl group being either allyl or a lower alkyl group having up to 5 carbon atoins. The resin is prepared by polymerizing compounds such as alkyl-diallyl phosphate and triallyl phosphate in the presence of a free radical generating substance and then partially hydrolyzing the resulting polymer to cause partial replacement of organic radicals by cations. A preferred free radical gencrating agent is dibenzoyl peroxide. The partial hydrolysis is brought about by refluxing the polymer with concentrated aqueous NaOH for three or four hours.

  1. Radiation initiated copolymerization of allyl alcohol with acrylonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Solpan, Dilek; Guven, Olgun [Hacettepe Univ., Ankara (Turkey). Dept. of Chemistry


    Copolymerization of allyl alcohol (AA) with acrylonitrile (AN) initiated by {gamma}-rays has been investigated to determine the respective reactivity ratios. Three different experimental techniques, namely Fourier Transform Infrared (FTIR), Ultraviolet (UV/vis) and elemental analysis (EA) have been used for the determination of copolymer compositions. Fineman-Ross (FR), Kelen-Tudos (KT), Non-Linear Least Square (NLLS) Analysis and Q-e methods have been applied to the three sets of experimental data. It has been concluded that data obtained from elemental analysis as applied to the Non-Linear Least Square approach gave the most reliable reactivity ratios as 2.09 and 0.40 for acrylonitrile and allyl alcohol, respectively. (Author).

  2. Radiation initiated copolymerization of allyl alcohol with acrylonitrile (United States)

    Şolpan, Dilek; Güven, Olgun


    Copolymerization of allyl alcohol (AA) with acrylonitrile (AN) initiated by γ-rays has been investigated to determine the respective reactivity ratios. Three different experimental techniques, namely Fourier Transform Infrared (FTIR), Ultraviolet (UV/vis) and elemental analysis (EA) have been used for the determination of copolymer compositions. Fineman-Ross (FR), Kelen-Tüdös (KT), Non-Linear Least Square (NLLS) Analysis and Q-e methods have been applied to the three sets of experimental data. It has been concluded that data obtained from elemental analysis as applied to the Non-Linear Least Square approach gave the most reliable reactivity ratios as 2.09 and 0.40 for acrylonitrile and allyl alcohol, respectively.

  3. Rh2(esp)2-catalyzed allylic and benzylic oxidations. (United States)

    Wang, Yi; Kuang, Yi; Wang, Yuanhua


    The dirhodium(II) catalyst Rh2(esp)2 allows direct solvent-free allylic and benzylic oxidations by T-HYDRO with a remarkably low catalyst loading. This method is operationally simple and scalable at ambient temperature without the use of any additives. The high catalyst stability in these reactions may be attributed to a dirhodium(II,II) catalyst resting state, which is less prone to decomposition.

  4. Expedient synthesis of new cinnoline diones by Ru-catalyzed regioselective unexpected deoxygenation-oxidative annulation of propargyl alcohols with phthalazinones and pyridazinones. (United States)

    Rajkumar, Subramani; Antony Savarimuthu, S; Senthil Kumaran, Rajendran; Nagaraja, C M; Gandhi, Thirumanavelan


    Ruthenium-catalyzed simple, cascade and one-pot synthesis of cinnoline-fused diones has been carried out by the C-H activation of phthalazinones/pyridazinones accomplished by the unusual deoxygenation of propargyl alcohols. The bond selectivity is accredited to the traceless directing nature of the hydroxyl group of propargyl alcohol. A sequential C-H activation, insertion and deoxy-oxidative annulation has been proposed based on the preliminary mechanistic study.

  5. Gold(I)-Assisted α-Allylation of Enals and Enones with Alcohols. (United States)

    Mastandrea, Marco Michele; Mellonie, Niall; Giacinto, Pietro; Collado, Alba; Nolan, Steven P; Miscione, Gian Pietro; Bottoni, Andrea; Bandini, Marco


    The intermolecular α-allylation of enals and enones occurs by the condensation of variously substituted allenamides with allylic alcohols. Cooperative catalysis by [Au(ItBu)NTf2] and AgNTf2 enables the synthesis of a range of densely functionalized α-allylated enals, enones, and acyl silanes in good yield under mild reaction conditions. DFT calculations support the role of an α-gold(I) enal/enone as the active nucleophilic species.

  6. An Unexpected Reaction of Allylic Propynoate under Palladium(Ⅱ) Catalysis

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Zhao-Guo(张兆国); LU,Xi-Yan(陆熙炎); LANG,Shen-Hui(郎深慧)


    Palladium (Ⅱ) catalyzed reactions of allyl propynoate in the presence of excess halide ions with or without allyl halide or acrolein were studied, yielding (E)-3-halo-2-allyl-acrylic acid as the sole product. A mechanism involving halopalladation, carbopalladation, ring opening and β-heteroatom elimination was prioposed and was further justified by the reaction with deuterated substrate.keywords palladium, enyne, halopalladation, carbopalladation,β-heteroatom elimination was proposed and was further justified by the reaction with deuterated substrate.

  7. Silver-Catalyzed Decarboxylative Allylation of Aliphatic Carboxylic Acids in Aqueous Solution. (United States)

    Cui, Lei; Chen, He; Liu, Chao; Li, Chaozhong


    Direct decarboxylative radical allylation of aliphatic carboxylic acids is described. With K2S2O8 as the oxidant and AgNO3 as the catalyst, the reactions of aliphatic carboxylic acids with allyl sulfones in aqueous CH3CN solution gave the corresponding alkenes in satisfactory yields under mild conditions. This site-specific allylation method is applicable to all primary, secondary, and tertiary alkyl acids and exhibits wide functional group compatibility.

  8. Allyl strontium compounds: synthesis, molecular structure and properties. (United States)

    Jochmann, Phillip; Davin, Julien P; Maslek, Stefanie; Spaniol, Thomas P; Sarazin, Yann; Carpentier, Jean-Francois; Okuda, Jun


    The synthesis and attempted isolation of neutral bis(allyl)strontium [Sr(C(3)H(5))(2)] (1) resulted in the isolation of potassium tris(allyl)strontiate K[Sr(C(3)H(5))(3)] (2). In situ generated 1 shows a pronounced Brønsted basicity, inducing polymerisation of THF. Ate complex 2 crystallises as [K(THF)(2){Sr(C(3)H(5))(3)}(THF)](∞) (2·(THF)(3)). The salt-like solid state structure of 2·(THF)(3) comprises a two-dimensional network of (μ(2)-η(3):η(3)-C(3)H(5))(-) bridged potassium and strontium centres. Synthesis of allyl complexes 1 and 2 utilised SrI(2), [Sr(TMDS)(2)] (3) (TMDS = tetramethyldisilazanide), and [Sr(HMDS)(2)] (HMDS = hexamethyldisilazanide) as strontium precursors. The solid state structure of previously reported [Sr(TMDS)(2)] (3) was established by X-ray single crystal analysis as a dissymmetric dimer of [Sr(2)(TMDS)(4)(THF)(3)] (3·(THF)(3)) with multiple Si-HSr agostic interactions. The presence of ether ligands (THF, 18-crown-6) influenced the Si-HSr resonances in the NMR spectra of the amido complex 3.

  9. Pattern of occurrence and occupancy of carbonylation sites in proteins

    DEFF Research Database (Denmark)

    Rao, R Shyama Prasad; Møller, Ian Max


    Proteins are targets for modification by reactive oxygen species, and carbonylation is an important irreversible modification that increases during oxidative stress. While information on protein carbonylation is accumulating, its pattern is not yet understood. We have made a meta......-analysis of the available literature data (456 carbonylation sites on 208 proteins) to appreciate the nature of carbonylation sites in proteins. Of the carbonylated (Arg, Lys, Pro, and Thr – RKPT) amino acids, Lys is the most abundant, whereas Pro is the most susceptible and Thr is the least susceptible. The incidence...... of carbonylation is lower in the N-terminal part of the protein primary sequence. Although a significantly higher number of carbonylated sites occur in Arg-, Lys-, Pro- and Thr-rich regions of proteins, the hydropathy environment of carbonylated sites is not significantly different from potential carbonylation...

  10. Effects of Iodosulfuron Methyl-sodium Plus Mesosulfuron-methyl and Tribenuron Methyl Plus Clodinafop Propargyl Mixed by Fenitrotion and Librel BMX Micronutrient Solution on Wheat Growth

    Directory of Open Access Journals (Sweden)

    V Sarabi


    Full Text Available Greenhouse experiment was conducted to assess the response of wheat to tank mixture of herbicides with insecticide and manure in Ferdowsi University of Mashhad, Iran. The experiment consisted of 8 treatments: 1- tribenuron methyl (15-20 g ha-1 + clodinafop propargyl (0.8 L ha-1 2- tribenuron methyl + clodinafop propargyl + fenitrotion (1.2 L ha-1 + librel (1 Kg ha-1 3- tribenuron methyl + clodinafop propargyl + fenitrotion 4- tribenuron methyl + clodinafop propargyl plus librel 5- iodosulfuron + mesosulfuron 6- iodosulfuron + mesosulfuron + fenitrotion + librel 7- iodosulfuron + mesosulfuron + fenitrotion 8- iodosulfuron + mesosulfuron + librel and 9- untreated control. The layout was a completely randomized design with 4 replications. The combinations were applied in tillering stage. On the base of our results combination of iodosulfuron methyl-sodium plus mesosulfuron-methyl, or plus fenitrotion, or plus librel, and iodosulfuron methyl-sodium plus mesosulfuron-methyl, or plus fenitrotion caused the most reduction in wheat height by 20% and 15%, leaf area by 44% and 39%, leaf fresh weight by 40% and 38%, shoot fresh weight by 36% and 32%, leaf dry weight by 30% and 25% and shoot dry weight by 37% and 29%, respectively. Combination of tribenuron methyl plus clodinafop propargyl, or plus fenitrotion, or plus librel, and tribenuron methyl plus clodinafop propargyl, or plus fenitrotion reduced leaf area, fresh weight and dry weight of wheat plants, but this reduction was not as much as previous mixture. Mixture of two herbicides with librel showed no damaging effect on wheat plants.

  11. Carbonyl compounds indoors in a changing climate

    Directory of Open Access Journals (Sweden)

    Brimblecombe Peter


    Full Text Available Abstract Background Formic acid, acetic acid and formaldehyde are important compounds in the indoor environment because of the potential for these acids to degrade calcareous materials (shells, eggs, tiles and geological specimens, paper and corrode or tarnish metals, especially copper and lead. Carbonyl sulfide tarnishes both silver and copper encouraging the formation of surface sulfides. Results Carbonyls are evolved more quickly at higher temperatures likely in the Cartoon Gallery at Knole, an important historic house near Sevenoaks in Kent, England where the study is focused. There is a potential for higher concentrations to accumulate. However, it may well be that in warmer climates they will be depleted more rapidly if ventilation increases. Conclusions Carbonyls are likely to have a greater impact in the future.

  12. Catalyst-free synthesis of skipped dienes from phosphorus ylides, allylic carbonates, and aldehydes via a one-pot SN2' allylation-Wittig strategy. (United States)

    Xu, Silong; Zhu, Shaoying; Shang, Jian; Zhang, Junjie; Tang, Yuhai; Dou, Jianwei


    A catalyst-free allylic alkylation of stabilized phosphorus ylides with allylic carbonates via a regioselective SN2' process is presented. Subsequent one-pot Wittig reaction with both aliphatic and aromatic aldehydes as well as ketenes provides structurally diverse skipped dienes (1,4-dienes) in generally high yields and moderate to excellent stereoselectivity with flexible substituent patterns. This one-pot SN2' allylation-Wittig strategy constitutes a convenient and efficient synthetic method for highly functionalized skipped dienes from readily available starting materials.

  13. A route to hydroxylfluorenes: TsOH-mediated condensation reactions of 1,3-diketones with propargylic alcohols

    KAUST Repository

    Yao, Liangfeng


    An efficient method of preparing hydroxylfluorenes by TsOH-mediated tandem alkylation/rearrangements of propargylic alcohols with 1,3-diketones is described. These reactions are accomplished in moderate to good yields under mild conditions to offer a straightforward and convenient one step synthetic route to hydroxylfluorene derivatives through a plausible mechanism involving a sequence of dehydration, addition, rearrangement and aromatization. This journal is © The Royal Society of Chemistry 2012.

  14. Catalytic membrane-installed microchannel reactors for one-second allylic arylation. (United States)

    Yamada, Yoichi M A; Watanabe, Toshihiro; Torii, Kaoru; Uozumi, Yasuhiro


    A variety of catalytic membranes of palladium-complexes with linear polymer ligands were prepared inside a microchannel reactor via coordinative and ionic molecular convolution to provide catalytic membrane-installed microdevices, which were applied to the instantaneous allylic arylation reaction of allylic esters and aryl boron reagents under microflow conditions to afford the corresponding coupling products within 1 second of residence time.

  15. Copper-Catalyzed SN2'-Selective Allylic Substitution Reaction of gem-Diborylalkanes. (United States)

    Zhang, Zhen-Qi; Zhang, Ben; Lu, Xi; Liu, Jing-Hui; Lu, Xiao-Yu; Xiao, Bin; Fu, Yao


    A Cu/(NHC)-catalyzed SN2'-selective substitution reaction of allylic electrophiles with gem-diborylalkanes is reported. Different substituted gem-diborylalkanes and allylic electrophiles can be employed in this reaction, and various synthetic valuable functional groups can be tolerated. The asymmetric version of this reaction was initially researched with chiral N-heterocyclic carbene (NHC) ligands.

  16. Allyl sulphides in olefin metathesis: catalyst considerations and traceless promotion of ring-closing metathesis. (United States)

    Edwards, Grant A; Culp, Phillip A; Chalker, Justin M


    Allyl sulphides are reactive substrates in ruthenium-catalysed olefin metathesis reactions, provided each substrate is matched with a suitable catalyst. A profile of catalyst activity is described, along with the first demonstration of allyl sulphides as traceless promoters in relayed ring-closing metathesis reactions.

  17. Memory effects in palladium-catalyzed allylic Alkylations of 2-cyclohexen-1-yl acetate

    DEFF Research Database (Denmark)

    Svensen, Nina; Fristrup, Peter; Tanner, David Ackland;


    The objective of this work was to characterize the enantiospecificity of the allylic alkylation of enantioenriched 2-cyclohexen-1-yl acetate with the enolate ion of dimethyl malonate catalyzed by unsymmetrical palladium catalysts. The precatalysts employed were (eta(3)-allyl)PdLCl, where L is a m...

  18. Corn oil and milk enhance the absorption of orally administered allyl isothiocyanate in rats. (United States)

    Ippoushi, Katsunari; Ueda, Hiroshi; Takeuchi, Atsuko


    Allyl isothiocyanate, a chief component of mustard oil, exhibits anticancer effects in both cultured cancer cells and animal models. The accumulation of the N-acetylcysteine conjugate of allyl isothiocyanate, the final metabolite of allyl isothiocyanate, in urine was evaluated in rats that were orally coadministered allyl isothiocyanate with fluids (e.g., water, green tea, milk, and 10% ethanol) or corn oil. The N-acetylcysteine conjugate of allyl isothiocyanate content in urine when allyl isothiocyanate (2 or 4μmol) was coadministered with corn oil or milk showed a greater increase (1.4±0.22 or 2.7±0.34μmol or 1.2±0.32 or 2.5±0.36μmol, 1.6- to 1.8-fold or 1.5-fold, respectively) than when allyl isothiocyanate (2 or 4μmol) was coadministered with water (0.78±0.10 or 1.7±0.17μmol). This result demonstrates that corn oil and milk enhance the absorption of allyl isothiocyanate in rats.

  19. Millimeter wave spectra of carbonyl cyanide ⋆ (United States)

    Bteich, S.B.; Tercero, B.; Cernicharo, J.; Motiyenko, R.A.; Margulès, L.; Guillemin, J.-C.


    Context More than 30 cyanide derivatives of simple organic molecules have been detected in the interstellar medium, but only one dicarbonitrile has been found and that very recently. There is still a lack of high-resolution spectroscopic data particularly for dinitriles derivatives. The carbonyl cyanide molecule is a new and interesting candidate for astrophysical detection. It could be formed by the reaction of CO and CN radicals, or by substitution of the hydrogen atom by a cyano group in cyanoformaldehyde, HC(=O)CN, that has already been detected in the interstellar medium. Aims The available data on the rotational spectrum of carbonyl cyanide is limited in terms of quantum number values and frequency range, and does not allow accurate extrapolation of the spectrum into the millimeter-wave range. To provide a firm basis for astrophysical detection of carbonyl cyanide we studied its millimeter-wave spectrum. Methods The rotational spectrum of carbonyl cyanide was measured in the frequency range 152 - 308 GHz and analyzed using Watson’s A- and S-reduction Hamiltonians. Results The ground and first excited state of v5 vibrational mode were assigned and analyzed. More than 1100 distinct frequency lines of the ground state were fitted to produce an accurate set of rotational and centrifugal distortion constants up to the eighth order. The frequency predictions based on these constants should be accurate enough for astrophysical searches in the frequency range up to 500 GHz and for transition involving energy levels with J ≤ 100 and Ka ≤ 42. Based on the results we searched for interstellar carbonyl cyanide in available observational data without success. Thus, we derived upper limits to its column density in different sources. PMID:27738349

  20. Construction of an Asymmetric Quaternary Carbon Center via Allylation of Hydrazones

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Bum; Satyender, Apuri; Jang, Doo Ok [Yonsei Univ., Wonju (Korea, Republic of)


    Asymmetric indium-mediated allylation of imine derivatives bearing a chiral auxiliary is a reliable strategy for the synthesis of chiral homoallylic amines. Various techniques for indium-mediated stereoselective allylation of imines bearing a chiral auxiliary have been reported. In 1997 Loh and co-workers reported indium-mediated allylation with imines derived from L-valine methyl ester. Since then, many forms of indium-mediated allylation bearing a chiral auxiliary have been reported, including imines derived from (S)-valinol, (R)-phenylglycinol, uracil, (R)-phenylglycinol methyl ester, N-tert-butanesufinamide, and (1R,2S)-1-amino-2-indanol. However, the synthesis of chiral auxiliaries often involves a laborious multi-step synthesis with expensive reagents. Therefore, the development of readily accessible chiral auxiliaries for asymmetric indium-mediated all-ylation is in high demand.

  1. First Magnesium-mediated Carbonyl Benzylation in Water

    Institute of Scientific and Technical Information of China (English)

    DENG,Wei(邓维); TAN,Xiang-Hui(谭翔辉); LIU,Lei(刘磊); GUO,Qing-Xiang(郭庆祥)


    Catalyzed by AgNO3, Mg was found for the first time to be able to mediate the coupling reaction between aromatic aldehydes and benzyl bromide or chloride in water. The yields were slightly higher than the recent results for Mg-mediated allylation despite the fact that aqueous benzylation is intrinsically much harder than allylation. It was also found that the coupling reaction was chemoselective for aromatic aldehydes over aliphatic aldehydes, and chemoselective for aromatic aldehydes over aromatic ketones.

  2. Do garlic-derived allyl sulfides scavenge peroxyl radicals? (United States)

    Amorati, Riccardo; Pedulli, Gian Franco


    The chain-breaking antioxidant activities of two garlic-derived allyl sulfides, i.e. diallyl disulfide (1), the main component of steam-distilled garlic oil, and allyl methyl sulfide (3) were evaluated by studying the thermally initiated autoxidation of cumene or styrene in their presence. Although the rate of cumene oxidation was reduced by addition of both 1 and 3, the dependence on the concentration of the two sulfides could not be explained on the basis of the classic antioxidant mechanism as with phenolic antioxidants. The rate of oxidation of styrene, on the other hand, did not show significant changes upon addition of either 1 or 3. This unusual behaviour was explained in terms of the co-oxidant effect, consisting in the decrease of the autoxidation rate of a substrate forming tertiary peroxyl radicals (i.e. cumene) upon addition of little amounts of a second oxidizable substrate giving rise instead to secondary peroxyl radicals. The relevant rate constants for the reaction of ROO(.) with 1 and 3 were measured as 1.6 and 1.0 M(-1) s(-1), respectively, fully consistent with the H-atom abstraction from substituted sulfides. It is therefore concluded that sulfides 1 and 3 do not scavenge peroxyl radicals and therefore cannot be considered chain-breaking antioxidants.

  3. Theoretical Study on the Mechanism of the Gas-phase Reaction of Sc+ with Propargyl Alcohol

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yi-Ping; CHEN Hong-Yan; CHENG Wei-Xian; FENG Yu; YANG Li-Jun


    In order to elucidate the reaction mechanisms of reaction Sc+ with propargyl alcohol(PPA),the triplet potential energy surface for the reactions has been theoretically investigated using a DFT method.The geometries for the reactants,intermediates,transition states and products were completely optimized at B3LYP/DZVP level.The single point energy of each stationary point was calculated at MP4/(6-311+G** for C,H,O and Lanl2dz for Sc+)level.All the transition states were verified by the vibrational analysis and the internal reaction coordinate(IRC)calculations.The present results show that the reaction takes an insertion-elimination mechanism both along the O-H and C-O bond activation branches,but the C-O bond activation is much more favorable in energy than the O-H bond activation.All theoretical results not only support the existing conclusions inferred from early experiment,but also complement the pathway and mechanism for this reaction.

  4. Isomerization of propargyl cation to cyclopropenyl cation: Mechanistic elucidations and effects of lone pair donors

    Indian Academy of Sciences (India)

    Zodinpuia Pachuau; Kiew S Kharnaior; R H Duncan Lyngdoh


    This ab initio study examines two pathways (one concerted and the other two-step) for isomerization of the linear propargyl cation to the aromatic cyclopropenyl cation, also probing the phenomenon of solvation of this reaction by simple lone pair donors (NH3, H2O, H2S and HF) which bind to the substrate at two sites. Fully optimized geometries at the B3LYP/6-31G(d) level were used, along with single point QCISD(T)/6-311+G(d,p) and accurate G3 level calculations upon the DFT optimized geometries. For the unsolvated reaction, the two-step second pathway is energetically favoured over the one-step first pathway. Lone pair donor affinity for the various C3H$^{+}_{3}$ species follows the uniform order NH3 > H2S>H2O>HF. The activation barriers for the solvated isomerizations decrease in the order HF>H2O>H2S>NH3 for both pathways. The number of lone pairs on the donor heteroatom as well as the heteroatom electronegativity are factors related to both these trends. Compared to the unsolvated cases, the solvated reactions have transition states which are usually ‘later’ in position along the reaction coordinate, validating the Hammond postulate.

  5. Why base-catalyzed isomerization of N-propargyl amides yields mostly allenamides rather than ynamides

    Directory of Open Access Journals (Sweden)

    Armando Navarro-Vázquez


    Full Text Available The base-catalyzed isomerization of N-propargylamides or carbamates may furnish N-allenyl compounds (allenamides/allencarbamates or further evolve to N-alkynyl compounds (ynamides or yncarbamates. The particular fate of this reaction varies from experiment to experiment and there is no clear rule for predicting the reaction outcome for a particular structure. With the support of ab initio and DFT computations, this work shows that observed results can be explained by assuming an exchange equilibrium between energetically close N-propargyl, allenyl and N-alkynyl forms and that the reaction outcome correlates to a particular equilibrium mixture. Due to the very small energy gap between the N-allenyl and N-alkynyl forms, small structural changes may easily alter the equilibrium position, explaining the variety of observed experimental results. Based on CBS-QB3 computations, the ωB97 functional provided reasonably accurate isomerization energies and could successfully predict the experimentally observed behavior for several examples from the literature.

  6. Photodissociation of the Propargyl (C3D3) Radicals at 248 nm and 193 nm

    Energy Technology Data Exchange (ETDEWEB)

    Neumark., D.M.; Crider, P.E.; Castiglioni, L.; Kautzman, K.K.


    The photodissociation of perdeuterated propargyl (D{sub 2}CCCD) and propynyl (D{sub 3}CCC) radicals was investigated using fast beam photofragment translational spectroscopy. Radicals were produced from their respective anions by photodetachment at 540 nm and 450 nm (below and above the electron affinity of propynyl). The radicals were then photodissociated by 248 nm or 193 nm light. The recoiling photofragments were detected in coincidence with a time- and position-sensitive detector. Three channels were observed: D{sub 2} loss, CD + C{sub 2}D{sub 2}, and CD{sub 3} + C{sub 2}. Obervation of the D loss channel was incompatible with this experiment and was not attempted. Our translational energy distributions for D{sub 2} loss peaked at nonzero translational energy, consistent with ground state dissociation over small (< 1 eV) exit barriers with respect to separated products. Translational energy distributions for the two heavy channels peaked near zero kinetic energy, indicating dissociation on the ground state in the absence of exit barriers.

  7. Conformations of propargyl alcohol and its interaction with acetylene: A matrix isolation infrared and DFT computations (United States)

    Sundararajan, K.; Gopi, R.; Ramanathan, N.


    Conformations of propargyl alcohol (PA) were studied using matrix isolation infrared spectroscopy. DFT computations using 6-311++G(d,p) basis set on the PA molecule identified two minima; gauche (g-PA) and trans (t-PA). Comparison of infrared spectra of PA trapped in Ar, N2 and Xe matrices with computations showed the evidence of the ground state g-PA conformer. Four minima were optimized on the potential energy surface for the hydrogen-bonded interaction of g-PA and acetylene (C2H2), corresponding to complex A (Csbnd H⋯O), complex B (Osbnd H⋯π) and complex C and D (Csbnd H⋯π). The structure, energies and the vibrational wavenumbers were computed for these complexes at B3LYP/6-311++G (d,p) level of theory. The infrared spectra of the hydrogen-bonded complexes between C2H2 and g-PA were studied in Ar matrix. The infrared spectra recorded under matrix isolation conditions revealed the formation of two types of complexes A (Csbnd H⋯O) and B (Osbnd H⋯π). Formation of these complexes was evidenced from the shifts in the vibrational wavenumber of the modes involving the C2H2 and PA submolecules.

  8. Oxidation of Reduced Sulfur Species: Carbonyl Sulfide

    DEFF Research Database (Denmark)

    Glarborg, Peter; Marshall, Paul


    A detailed chemical kinetic model for oxidation of carbonyl sulfide (OCS) has been developed, based on a critical evaluation of data from the literature. The mechanism has been validated against experimental results from batch reactors, flow reactors, and shock tubes. The model predicts satisfact......A detailed chemical kinetic model for oxidation of carbonyl sulfide (OCS) has been developed, based on a critical evaluation of data from the literature. The mechanism has been validated against experimental results from batch reactors, flow reactors, and shock tubes. The model predicts...... by the competition between chain‐branching and ‐propagating steps; modeling predictions are particularly sensitive to the branching fraction for the OCS + O reaction to form CO + SO or CO2 + S....

  9. Carbonyl compounds generated from electronic cigarettes. (United States)

    Bekki, Kanae; Uchiyama, Shigehisa; Ohta, Kazushi; Inaba, Yohei; Nakagome, Hideki; Kunugita, Naoki


    Electronic cigarettes (e-cigarettes) are advertised as being safer than tobacco cigarettes products as the chemical compounds inhaled from e-cigarettes are believed to be fewer and less toxic than those from tobacco cigarettes. Therefore, continuous careful monitoring and risk management of e-cigarettes should be implemented, with the aim of protecting and promoting public health worldwide. Moreover, basic scientific data are required for the regulation of e-cigarette. To date, there have been reports of many hazardous chemical compounds generated from e-cigarettes, particularly carbonyl compounds such as formaldehyde, acetaldehyde, acrolein, and glyoxal, which are often found in e-cigarette aerosols. These carbonyl compounds are incidentally generated by the oxidation of e-liquid (liquid in e-cigarette; glycerol and glycols) when the liquid comes in contact with the heated nichrome wire. The compositions and concentrations of these compounds vary depending on the type of e-liquid and the battery voltage. In some cases, extremely high concentrations of these carbonyl compounds are generated, and may contribute to various health effects. Suppliers, risk management organizations, and users of e-cigarettes should be aware of this phenomenon.

  10. Carbonyl Compounds Generated from Electronic Cigarettes

    Directory of Open Access Journals (Sweden)

    Kanae Bekki


    Full Text Available Electronic cigarettes (e-cigarettes are advertised as being safer than tobacco cigarettes products as the chemical compounds inhaled from e-cigarettes are believed to be fewer and less toxic than those from tobacco cigarettes. Therefore, continuous careful monitoring and risk management of e-cigarettes should be implemented, with the aim of protecting and promoting public health worldwide. Moreover, basic scientific data are required for the regulation of e-cigarette. To date, there have been reports of many hazardous chemical compounds generated from e-cigarettes, particularly carbonyl compounds such as formaldehyde, acetaldehyde, acrolein, and glyoxal, which are often found in e-cigarette aerosols. These carbonyl compounds are incidentally generated by the oxidation of e-liquid (liquid in e-cigarette; glycerol and glycols when the liquid comes in contact with the heated nichrome wire. The compositions and concentrations of these compounds vary depending on the type of e-liquid and the battery voltage. In some cases, extremely high concentrations of these carbonyl compounds are generated, and may contribute to various health effects. Suppliers, risk management organizations, and users of e-cigarettes should be aware of this phenomenon.

  11. A Mechanistic Study of Direct Activation of Allylic Alcohols in Palladium Catalyzed Amination Reactions


    Yasemin Gumrukcu; Bas de Bruin; Reek, Joost N. H.


    We here report a computational approach on the mechanism of allylicamination reactions using allyl-alcohols and amines as the substrates and phosphoramidite palladium catalyst 1a, which operates in the presence of catalytic amount of 1,3-diethylurea as a co-catalyst. DFT calculations showed a cooperative hydrogen-bonding array between the urea moiety and the hydroxyl group of the allyl alcohol, which strengthens the hydrogen bond between the O-H moiety of the coordinated allyl-alcohol and th...

  12. Highly stereoselective synthesis of functionalized 1,3-dienes from a new allyl bromide

    Directory of Open Access Journals (Sweden)

    Asma Fray


    Full Text Available New and highly functionalized 1,3-dienes 3 and 4 have been synthesized via two different pathways starting from allyl bromide 1. Firstly, the reaction of allyl bromide 1 with triethylphosphite leads to an allylphosphonate 2, which undergoes the Wittig-Horner reaction with a range of saturated and unsaturated aldehydes gives rise to the corresponding 1,3-dienes 3. Secondly, a highly stereoselective reaction between allyl bromide 1 and nitroalkane salts, offers the possibility to obtaining functionalized (E-1,3-dienes 4.

  13. Carbonyl Emissions from Gasoline and Diesel Motor Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Destaillats, Hugo; Jakober, Chris A.; Robert, Michael A.; Riddle, Sarah G.; Destaillats, Hugo; Charles, M. Judith; Green, Peter G.; Kleeman, Michael J.


    Carbonyls from gasoline powered light-duty vehicles (LDVs) and heavy-duty diesel powered vehicles (HDDVs) operated on chassis dynamometers were measured using an annular denuder-quartz filter-polyurethane foam sampler with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine derivatization and chromatography-mass spectrometry analyses. Two internal standards were utilized based on carbonyl recovery, 4-fluorobenzaldehyde forcarbonyls and 6-fluoro-4-chromanone for>_C8 compounds. Gas- and particle-phase emissions for 39 aliphatic and 20 aromatic carbonyls ranged from 0.1 ? 2000 ?g/L fuel for LDVs and 1.8 - 27000 mu g/L fuel for HDDVs. Gas-phase species accounted for 81-95percent of the total carbonyls from LDVs and 86-88percent from HDDVs. Particulate carbonyls emitted from a HDDV under realistic driving conditions were similar to concentrations measured in a diesel particulate matter (PM) standard reference material. Carbonyls accounted for 19percent of particulate organic carbon (POC) emissions from low-emission LDVs and 37percent of POC emissions from three-way catalyst equipped LDVs. This identifies carbonyls as one of the largest classes of compounds in LDV PM emissions. The carbonyl fraction of HDDV POC was lower, 3.3-3.9percent depending upon operational conditions. Partitioning analysis indicates the carbonyls had not achieved equilibrium between the gas- and particle-phase under the dilution factors of 126-584 used in the current study.

  14. Silver(I)-Catalyzed Synthesis of β-Oxopropylcarbamates from Propargylic Alcohols and CO2 Surrogate: A Gas-Free Process. (United States)

    Song, Qing-Wen; Zhou, Zhi-Hua; Yin, Hong; He, Liang-Nian


    The utilization of carbon dioxide poses major challenges owing to its high thermodynamic stability and kinetic inertness. To circumvent these problems, a simple reaction system is reported comprising ammonium carbamates as carbon dioxide surrogates, propargylic alcohols, and a silver(I) catalyst, for the effective conversion of a wide range of alcohols and secondary amines into the corresponding β-oxopropylcarbamates. A key feature of this strategy includes quantitative use of a carbon resource with high product yields under gas-free and mild reaction conditions. Notably, this catalytic protocol also works well for the carboxylative cyclization of propargylic amines and carbon dioxide surrogates to afford 2-oxazolidinones.

  15. A Novel Thin Film Resistive Humidity Sensor Based on Soluble Conjugated Polymer: (propionic acid)-co-(propargyl alcohol)

    Institute of Scientific and Technical Information of China (English)


    A novel soluble conjugated copolymer (propionic acid)-co-(propargyl alcohol) (PA-co-OHP) has been synthesized for the first time using a new palladium acetylide catalyst Pd(PPh3)2 (CoCC(CH3)2OH)2 (PPB). Thin film resistive humidity sensor based on the copolymer doped with HClO-4 was prepared. The impedance of the sensor changed from 103~107 W in 95%~30%RH, and the response of that is very quick (<6 sec.). Preliminary results show the copolymer is a promising humidity sensitive material.

  16. Propargyl Vinyl Ethers and Tertiary Skipped Diynes: Two Pluripotent Molecular Platforms for Diversity-Oriented Synthesis. (United States)

    Tejedor, David; López-Tosco, Sara; Méndez-Abt, Gabriela; Cotos, Leandro; García-Tellado, Fernando


    During the last years, we have been involved in the development of a diversity-oriented synthetic strategy aimed at transforming simple, linear, and densely functionalized molecular platforms into collections of topologically diverse scaffolds incorporating biologically relevant structural motifs such as N- and O- heterocycles, multifunctionalized aromatic rings, fused macrocycles, etc. The strategy merges the concepts of pluripotency (the property of an array of chemical functionalities to express different chemical outcomes under different chemical environments) and domino chemistry (chemistry based on processes involving two or more bond-forming transformations that take place while the initial reaction conditions are maintained, with the subsequent reaction resulting as a consequence of the functionality installed in the previous one) to transform common multifunctional substrates into complex and diverse molecular frameworks. This design concept constitutes the ethos of the so-called branching cascade strategy, a branch of diversity-oriented synthesis focused on scaffold diversity generation. Two pluripotent molecular platforms have been extensively studied under this merging (branching) paradigm: C4-O-C3 propargyl vinyl ethers (PVEs) and C7 tertiary skipped diynes (TSDs). These are conveniently constructed from simple and commercially available raw materials (alkyl propiolates, ketones, aldehydes, acid chlorides) through multicomponent manifolds (ABB' three-component reaction for PVEs; A2BB' four-component reaction for TSDs) or a simple two-step procedure (for PVEs). Their modular origin facilitates their structural/functional diversification without increasing the number of synthetic steps for their assembly. These two pluripotent molecular platforms accommodate a well-defined and dense array of through-bond/through-space interrelated functionalities on their structures, which defines their primary reactivity principles and establishes the reactivity profile

  17. Chemoselective allylation of ketones in ionic liquids containing sulfonate anions. (United States)

    Galletti, Paola; Moretti, Fabio; Samorì, Chiara; Tagliavini, Emilio


    The chemoselective addition of tetraallyltin to dialkyl, alkenyl-alkyl, and alkynyl-alkyl ketones can be performed with high yields in N-methyl-N-butylpyrrolidinium trifuoromethansulfonate (MBP-Tf). Other room temperature ionic liquids (RTILs) can also be successfully employed if some sulfonic acid is added. The reaction is very sensitive to the electronic properties of the substrate. Aryl alkyl ketones bearing electron-withdrawing substituents behave like dialkyl ketones and react promptly; on the contrary, electron-rich aryl alkyl ketones react sluggishly, which allows selective competitive allylation of dialkyl substrates to occur. The ionic liquid solvent can be easily recycled, which meets the green chemistry principles of selectivity and reuse of chemicals. NMR spectroscopic data support the formation of tin-triflate catalysts in situ.

  18. Aerobic Linear Allylic C-H Amination: Overcoming Benzoquinone Inhibition. (United States)

    Pattillo, Christopher C; Strambeanu, Iulia I; Calleja, Pilar; Vermeulen, Nicolaas A; Mizuno, Tomokazu; White, M Christina


    An efficient aerobic linear allylic C-H amination reaction is reported under palladium(II)/bis-sulfoxide/Brønsted base catalysis. The reaction operates under preparative, operationally simple conditions (1 equiv of olefin, 1 atm O2 or air) with reduced Pd(II)/bis-sulfoxide catalyst loadings while providing higher turnovers and product yields than systems employing stoichiometric benzoquinone (BQ) as the terminal oxidant. Pd(II)/BQ π-acidic interactions have been invoked in various catalytic processes and are often considered beneficial in promoting reductive functionalizations. When such electrophilic activation for functionalization is not needed, however, BQ at high concentrations may compete with crucial ligand (bis-sulfoxide) binding and inhibit catalysis. Kinetic studies reveal an inverse relationship between the reaction rate and the concentration of BQ, suggesting that BQ is acting as a ligand for Pd(II) which results in an inhibitory effect on catalysis.

  19. Effects of S-propargyl-cysteine (SPRC in caerulein-induced acute pancreatitis in mice.

    Directory of Open Access Journals (Sweden)

    Jenab N Sidhapuriwala

    Full Text Available Hydrogen sulfide (H(2S, a novel gaseous messenger, is synthesized endogenously from L-cysteine by two pyridoxal-5'-phosphate-dependent enzymes, cystathionine β-synthase (CBS and cystathionine γ-lyase (CSE. S-propargyl-cysteine (SPRC is a slow H(2S releasing drug that provides cysteine, a substrate of CSE. The present study was aimed to investigate the effects of SPRC in an in vivo model of acute pancreatitis (AP in mice. AP was induced in mice by hourly caerulein injections (50 µg/kg for 10 hours. Mice were treated with SPRC (10 mg/kg or vehicle (distilled water. SPRC was administered either 12 h before or 3 h before the induction of pancreatitis. Mice were sacrificed 1 h after the last caerulein injection. Blood, pancreas and lung tissues were collected and processed to measure the plasma amylase, plasma H(2S, myeloperoxidase (MPO activities and cytokine levels in pancreas and lung. The results revealed that significant reduction of inflammation, both in pancreas and lung was associated with SPRC given 3 h prior to the induction of AP. Furthermore, the beneficial effects of SPRC were associated with reduction of pancreatic and pulmonary pro-inflammatory cytokines and increase of anti-inflammatory cytokine. SPRC administered 12 h before AP induction did not cause significant improvement in pancreatic and lung inflammation. Plasma H(2S concentration showed significant difference in H(2S levels between control, vehicle and SPRC (administered 3 h before AP treatment groups. In conclusion, these data provide evidence for protective effects of SPRC in AP possibly by virtue of its slow release of endogenous H(2S.

  20. PAH growth initiated by propargyl addition: Mechanism development and computational kinetics

    KAUST Repository

    Raj, Abhijeet Dhayal


    Polycyclic aromatic hydrocarbon (PAH) growth is known to be the principal pathway to soot formation during fuel combustion, as such, a physical understanding of the PAH growth mechanism is needed to effectively assess, predict, and control soot formation in flames. Although the hydrogen abstraction C2H2 addition (HACA) mechanism is believed to be the main contributor to PAH growth, it has been shown to under-predict some of the experimental data on PAHs and soot concentrations in flames. This article presents a submechanism of PAH growth that is initiated by propargyl (C 3H3) addition onto naphthalene (A2) and the naphthyl radical. C3H3 has been chosen since it is known to be a precursor of benzene in combustion and has appreciable concentrations in flames. This mechanism has been developed up to the formation of pyrene (A4), and the temperature-dependent kinetics of each elementary reaction has been determined using density functional theory (DFT) computations at the B3LYP/6-311++G(d,p) level of theory and transition state theory (TST). H-abstraction, H-addition, H-migration, β-scission, and intramolecular addition reactions have been taken into account. The energy barriers of the two main pathways (H-abstraction and H-addition) were found to be relatively small if not negative, whereas the energy barriers of the other pathways were in the range of (6-89 kcal·mol-1). The rates reported in this study may be extrapolated to larger PAH molecules that have a zigzag site similar to that in naphthalene, and the mechanism presented herein may be used as a complement to the HACA mechanism to improve prediction of PAH and soot formation. © 2014 American Chemical Society.

  1. Biomarkers derived from heterolytic and homolytic cleavage of allylic hydroperoxides resulting from alkenone autoxidation

    Digital Repository Service at National Institute of Oceanography (India)

    Rontania, J.F.; Harji, R.; Volkmanc, J.K.

    , hydroxyacids and alkyldiols resulted from the reduction during the NaBH4 treatment of the corresponding aldehydes, ketoxyacids and ketoxyaldehydes formed from heterolytic or hemolytic cleavages of allylic hydroperoxyl groups resulting from the oxidation...

  2. Facile synthesis of allyl resinate monomer in an aqueous solution under microwave irradiation

    Indian Academy of Sciences (India)

    Yanju Lu; Mixia Wang; Zhendong Zhao; Yuxiang Chen; Shichao Xu; Jing Wang; Liangwu Bi


    We have developed a facile method for production of allyl resinate monomer (allyl rosin ester) via a phase transfer reaction under microwave irradiation. The synthesis of allyl resinate was conducted using allyl chloride and sodium resinate as starting materials in aqueous solution at 50°C for 30 min with a yield of 94.7%, which is 20% higher than conventional heating method. The products precipitated spontaneously from the aqueous phase after reaction, which significantly facilitated the subsequent separation of monomer products. The synthesized monomer product appeared as a viscous liquid, with a viscosity of 460 mPa·s at 25°C and a density of 1.0469 g/cm3. The physical and chemical properties suggested that the synthesized monomer has great potential for free radical polymerization.

  3. Acute inhalation toxicity of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Benson, J.M.; Hahn, F.F.; Barr, E.B. [and others


    Carbonyl sulfide (COS), a colorless gas, is a side product of industrial procedures sure as coal hydrogenation and gasification. It is structurally related to and is a metabolite of carbon disulfide. COS is metabolized in the body by carbonic anhydrase to hydrogen sulfide (H{sub 2}S), which is thought to be responsible for COS toxicity. No threshold limit value for COS has been established. Results of these studies indicate COS (with an LC{sub 50} of 590 ppm) is slightly less acutely toxic than H{sub 2}S (LC{sub 50} of 440 ppm).

  4. Selective epoxidation of allylic alcohols with a titania-silica aerogel

    Energy Technology Data Exchange (ETDEWEB)

    Dusi, M.; Mallat, T.; Baiker, A. [Lab. of Technical Chemistry, Swiss Federal Inst. of Technology, ETH-Zentrum, Zuerich (Switzerland)


    An amorphous mesoporous titania-silica aerogel (20 wt%TiO{sub 2} - 80 wt% SiO{sub 2}) and tert.-butylhydroperoxide (TBHP) have been used for the epoxidation of various allylic alcohols. Allylic alcohols possessing an internal double bond were more reactive than those with a terminal C=C bond. Epoxide selectivities could be improved by addition of (basic) zeolite 4 A and NaHCO{sub 3} to the reaction mixture. (orig.)

  5. Direct use of allylic alcohols for platinum-catalyzed monoallylation of amines. (United States)

    Utsunomiya, Masaru; Miyamoto, Yoshiki; Ipposhi, Junji; Ohshima, Takashi; Mashima, Kazushi


    A new direct catalytic amination of allylic alcohols promoted by the combination of platinum and a large bite-angle ligand DPEphos was developed in which the allylic alcohol was effectively converted to a pi-allylplatinum intermediate without the use of an activating reagent. The use of the DPEphos ligand was essential for obtaining high catalyst activity and high monoallylation selectivity of primary amines, allowing the formation of a variety of monoallylation products in good to excellent yield.

  6. Pollution survey of carbonyl compounds in train air

    Institute of Scientific and Technical Information of China (English)

    LU Hao; ZHU Lizhong


    The train iS an important vehicle in China,but its air quality has important impacts on passengers' health.In this work,pollution from carbonyl compounds was measured in the air of six trains.The obiectives of this work were to investigate carbonyl compound levels in selected air from trains,identify their emission sources,and assess the intake of carbonyl compounds for passengers.The methods for sampling and analyzing 10 carbonyl compounds such as formaldehyde,acetaldehyde,acrolein,acetone,propionalde hyde,crotonaldehyde,butyraldehyde,benzaldehyde,cyclo hexanone,and valeraldehyde in indoor air were proposed with the sampling efficiency,recovery,and detection limit being 92%-100%,91%-104%,and 0.26-0.82 ng/m3,respec tively.It was indicated that the total concentrations of carbonyl compounds were 0.159-0.2828 mg/m3 with the average concentration of 0.2330 mg/m3.The average concen trations of formaldehyde.acetaldehyde and acetone were 0.0922,0.0499,and 0.0580 mg/m3,accounting for 42.6%,21.4%.and 24.9% of the total concentrations of carbonyl compounds,respectively.The carbonyl compounds probably came from woodwork and cigarette smoking.The intake of carbonyl compounds for the passengers was approximately 0.043-0.076 mg/h.The carbonyl compounds in train air could be harmful to human health.

  7. Effect of hydrogen atoms on the structures of trinuclear metal carbonyl clusters: trinuclear manganese carbonyl hydrides. (United States)

    Liu, Xian-mei; Wang, Chao-yang; Li, Qian-shu; Xie, Yaoming; King, R Bruce; Schaefer, Henry F


    The structures of the trinuclear manganese carbonyl hydrides H(3)Mn(3)(CO)(n) (n = 12, 11, 10, 9) have been investigated by density functional theory (DFT). Optimization of H(3)Mn(3)(CO)(12) gives the experimentally known structure in which all carbonyl groups are terminal and each edge of a central Mn(3) equilateral triangle is bridged by a single hydrogen atom. This structure establishes the canonical distance 3.11 A for the Mn-Mn single bond satisfying the 18-electron rule. The central triangular (mu-H)(3)Mn(3) unit is retained in the lowest energy structure of H(3)Mn(3)(CO)(11), which may thus be derived from the H(3)Mn(3)(CO)(12) structure by removal of a carbonyl group with concurrent conversion of one of the remaining carbonyl groups into a semibridging carbonyl group to fill the resulting hole. The potential energy surface of H(3)Mn(3)(CO)(10) is relatively complicated with six singlet and five triplet structures. One of the lower energy H(3)Mn(3)(CO)(10) structures has one of the hydrogen atoms bridging the entire Mn(3) triangle and the other two hydrogen atoms bridging Mn-Mn edges. This H(3)Mn(3)(CO)(10) structure achieves the favored 18-electron configuration with a very short MnMn triple bond of 2.36 A. The other low energy H(3)Mn(3)(CO)(10) structure retains the (mu-H)(3)Mn(3) core of H(3)Mn(3)(CO)(12) but has a unique six-electron donor eta(2)-mu(3) carbonyl group bridging the entire Mn(3) triangle similar to the unique carbonyl group in the known compound Cp(3)Nb(3)(CO)(6)(eta(2)-mu(3)-CO). For H(3)Mn(3)(CO)(9) a structure with a central (mu(3)-H)(2)Mn(3) trigonal bipyramid lies >20 kcal/mol below any of the other structures. Triplet structures were found for the unsaturated H(3)Mn(3)(CO)(n) (n = 11, 10, 9) systems but at significantly higher energies than the lowest lying singlet structures.

  8. Effect of allyl isothiocyanate on developmental toxicity in exposed Xenopus laevis embryos

    Directory of Open Access Journals (Sweden)

    John Russell Williams


    Full Text Available The pungent natural compound allyl isothiocyanate isolated from the seeds of Cruciferous (Brassica plants such as mustard is reported to exhibit numerous beneficial health-promoting antimicrobial, antifungal, anticarcinogenic, cardioprotective, and neuroprotective properties. Because it is also reported to damage DNA and is toxic to aquatic organisms, the objective of the present study was to determine whether it possesses teratogenic properties. The frog embryo teratogenesis assay-Xenopus (FETAX was used to determine the following measures of developmental toxicity of the allyl isothiocyanate: (a 96-h LC50, defined as the median concentration causing 50% embryo lethality; (b 96-h EC50, defined as the median concentration causing 50% malformations of the surviving embryos; and (c teratogenic malformation index (TI, equal to 96-h LC50/96-h EC50. The quantitative results and the photographs of embryos before and after exposure suggest that allyl isothiocyanate seems to exhibit moderate teratogenic properties. The results also indicate differences in the toxicity of allyl isothiocyanate toward exposed embryos observed in the present study compared to reported adverse effects of allyl isothiocyanate in fish, rodents, and humans. The significance of the results for food safety and possible approaches to protect against adverse effects of allyl isothiocyanate are discussed.

  9. Carbonyl sulfide: No remedy for global warming (United States)

    Taubman, Steven J.; Kasting, James F.


    The enhancement of the stratospheric aerosol layer caused by the eruption of Mt. Pinatubo (June 15, 1991), and the subsequent cooling of the earth's lower atmosphere [Dutton and Christy, 1992; Minnis et al., 1993] shows that stratospheric aerosols can have a strong effect on the earth's climate. This supports the notion that the intentional enhancement of the stratospheric aerosol layer through increased carbonyl sulfide (OCS) emissions might be an effective means for counteracting global warming. Through the use of a one-dimensional photochemical model, we investigate what effect such a program might have on global average stratospheric ozone. In addition, we consider the impact of enhanced OCS emissions on rainwater acidity and on the overall health of both plants and animals. We find that while the warming produced by a single CO2 doubling (1 to 4°C) might be offset with ozone losses of less than 5%, any attempt to use carbonyl sulfide as a permanent solution to global warming could result in depletion of global average ozone by 30% or more. We estimate that in order to achieve cooling of 4°C rainwater pH would fall to between 3.5 and 3.8. Finally, a 4°C cooling at the surface will require that ambient near ground OCS levels rise to above 10 ppmv which is probably greater than the safe exposure limit for humans. Thus, enhanced OCS emissions do not provide an environmentally acceptable solution to the problem of global warming.

  10. Silver(I)-catalyzed dual activation of propargylic alcohol and aziridine/azetidine: triggering ring-opening and endo-selective ring-closing in a cascade. (United States)

    Bera, Milan; Roy, Sujit


    [Ag(COD)(2)]PF(6) catalyzes the reaction between propargyl alcohols and N-tosylaziridines/azetidines leading to a diverse range of N,O-heterocycles, namely, oxazines, oxazepines, and oxazocines via ring-opening and ring-closing in a cascade.

  11. Cp*Rh(III)-Catalyzed Low Temperature C-H Allylation of N-Aryl-trichloro Acetimidamide. (United States)

    Debbarma, Suvankar; Bera, Sourav Sekhar; Maji, Modhu Sudan


    The readily synthesized trichloro acetimidamide was found to be an excellent directing group for the directed C-H-allylation reactions. Depending on the allylating agent used, selectively either mono- or diallylated products were readily synthesized. Moreover, the trichloro acetimidamide directing group was found to be highly efficient even at lower temperature for the C-H-allylation reaction. Due to mildness of the reaction conditions, double bond isomerization or cyclization to indole side product was not observed.

  12. Gold-catalyzed intermolecular coupling of sulfonylacetylene with allyl ethers: [3,3]- and [1,3]-rearrangements

    Directory of Open Access Journals (Sweden)

    Jungho Jun


    Full Text Available Gold-catalyzed intermolecular couplings of sulfonylacetylenes with allyl ethers are reported. A cooperative polarization of alkynes both by a gold catalyst and a sulfonyl substituent resulted in an efficient intermolecular tandem carboalkoxylation. Reactions of linear allyl ethers are consistent with the [3,3]-sigmatropic rearrangement mechanism, while those of branched allyl ethers provided [3,3]- and [1,3]-rearrangement products through the formation of a tight ion–dipole pair.

  13. High Resolution Infrared Spectroscopy of Propargyl Alcohol-Water Complex Embedded in Helium Nanodroplets (United States)

    Mani, Devendra; Pal, Nitish; Kaufmann, Matin; Schwaab, Gerhard; Havenith, Martina


    Propargyl alcohol (hereafter abbreviated as PA) is a molecule of astrophysical interest and has been probed extensively using microwave spectroscopy.1,2 It is a multifunctional molecule and offers multiple sites for hydrogen bonding interactions. Therefore, it has also attracted the attention of groups interested in weak intermolecular interactions. Recently, the Ar…PA complex3 and PA-dimer4 have been studied using microwave spectroscopy. More recently, there have been matrix-isolation infrared spectroscopic studies on PA-water5 and PA-acetylene6 complexes. In the present work, clusters of PA and water were formed in the helium nanodroplets and probed using a combination of infrared spectroscopy and mass spectrometry. Using ab-initio quantum mechanical calculations, PA-water clusters were optimised and five minimum structures were found on the potential energy hypersurface, which were used as a guidance to the experiments. We used D2O for the experiments since our laser sources at Bochum do not cover the IR spectral region of H2O. IR spectra of PA-D2O complex were recorded in the region of symmetric and antisymmetric stretches of the bound D2O. Multiple signals were found in these regions which were dependent on the concentration of PA as well as D2O. Using pickup curves most of these signals could be assigned to 1:1 PA:D2O clusters. The ab-initio calculations helped in a definitive assignment of the spectra to the different conformers of PA-D2O complex. The details will be presented in the talk. References: 1. E. Hirota, J. Mol. Spec. 26, 335 (1968). 2. J.C. Pearson and B.J. Drouin, J. Mol. Spectrosc. 234, 149 (2005). 3. D. Mani and E. Arunan, ChemPhysChem 14, 754 (2013). 4. D. Mani and E. Arunan, J. Chem. Phys. 141, 164311 (2014). 5. J. Saini, K.S. Vishwanathan, J. Mol. Struct. 1118, 147 (2016). 6. K. Sundararajan et al., J. Mol. Struct. 1121, 26 (2016).

  14. Characterization of oxidative carbonylation on recombinant monoclonal antibodies. (United States)

    Yang, Yi; Stella, Cinzia; Wang, Weiru; Schöneich, Christian; Gennaro, Lynn


    In the biotechnology industry, oxidative carbonylation as a post-translational modification of protein pharmaceuticals has not been studied in detail. Using Quality by Design (QbD) principles, understanding the impact of oxidative carbonylation on product quality of protein pharmaceuticals, particularly from a site-specific perspective, is critical. However, comprehensive identification of carbonylation sites has so far remained a very difficult analytical challenge for the industry. In this paper, we report for the first time the identification of specific carbonylation sites on recombinant monoclonal antibodies with a new analytical approach via derivatization with Girard's Reagent T (GRT) and subsequent peptide mapping with high-resolution mass spectrometry. Enhanced ionization efficiency and high quality MS(2) data resulted from GRT derivatization were observed as key benefits of this approach, which enabled direct identification of carbonylation sites without any fractionation or affinity enrichment steps. A simple data filtering process was also incorporated to significantly reduce false positive assignments. Sensitivity and efficiency of this approach were demonstrated by identification of carbonylation sites on both unstressed and oxidized antibody bulk drug substances. The applicability of this approach was further demonstrated by identification of 14 common carbonylation sites on three highly similar IgG1s. Our approach represents a significant improvement to the existing analytical methodologies and facilitates extended characterization of oxidative carbonylation on recombinant monoclonal antibodies and potentially other protein pharmaceuticals in the biotechnology industry.

  15. Synthesis of main-chain metal carbonyl organometallic macromolecules (MCMCOMs). (United States)

    Cao, Kai; Murshid, Nimer; Wang, Xiaosong


    Synthesis of main-chain metal carbonyl organometallic macromolecules (MCMCOMs) is difficult, mainly due to the instability of metal carbonyl complexes. Despite its challenge a number of MCMCOMs has been prepared by strategically using organometallic, organic, and polymer synthetic chemistry. Main contributions to this research field were reported by the groups of Tyler, Pannell, and Wang and are briefly summarized in this article.

  16. Bifunctional dendrons for multiple carbohydrate presentation via carbonyl chemistry

    Directory of Open Access Journals (Sweden)

    Davide Bini


    Full Text Available The synthesis of new dendrons of the generations 0, 1 and 2 with a double bond at the focal point and a carbonyl group at the termini has been carried out. The carbonyl group has been exploited for the multivalent conjugation to a sample saccharide by reductive amination and alkoxyamine conjugation.

  17. Carbonyl-Olefin Exchange Reaction: Present State and Outlook (United States)

    Kalinova, Radostina; Jossifov, Christo

    The carbonyl-olefin exchange reaction (COER) is a new reaction between carbonyl group and olefin double bond, which has a formal similarity with the olefin metathesis (OM) - one carbon atom in the latter is replaced with an oxygen atom. Till now the new reaction is performed successfully only when the two functional groups (carbonyl group and olefin double bond) are in one molecule and are conjugated. The α, β-unsaturated carbonyl compounds (substituted propenones) are the compounds with such a structure. They polymerize giving substituted polyacetylenes. The chain propagation step of this polymerization is in fact the COER. The question arises: is it possible the COER to take place when the two functional groups are not in one molecule and are not conjugated, and could this reaction became an alternative of the existing carbonyl olefination reactions?

  18. Chiral Phosphoric Acid Catalyzed Enantioselective Allylation of Aldehydes with Allyltrichlorosilane%Chiral Phosphoric Acid Catalyzed Enantioselective Allylation of Aldehydes with Allyltrichlorosilane

    Institute of Scientific and Technical Information of China (English)

    程柯; 范甜甜; 孙健


    Easily accessible chiral phosphoric acid lb has been applied as efficient organocatalyst for the asymmetric al- lylation of aldehydes with allyltrichlorosilane. In the presence of 20 mol% of lb, the allylation of a broad range of aldehydes proceeded smoothly to give the corresponding homoallylic alcohol with up to 87% ee and 97% yield.

  19. Metal-free carbonylations by photoredox catalysis. (United States)

    Majek, Michal; Jacobi von Wangelin, Axel


    The synthesis of benzoates from aryl electrophiles and carbon monoxide is a prime example of a transition-metal-catalyzed carbonylation reaction which is widely applied in research and industrial processes. Such reactions proceed in the presence of Pd or Ni catalysts, suitable ligands, and stoichiometric bases. We have developed an alternative procedure that is free of any metal, ligand, and base. The method involves a redox reaction driven by visible light and catalyzed by eosin Y which affords alkyl benzoates from arene diazonium salts, carbon monoxide, and alcohols under mild conditions. Tertiary esters can also be prepared in high yields. DFT calculations and radical trapping experiments support a catalytic photoredox pathway without the requirement for sacrificial redox partners.

  20. Catalyst Initiation in the Oscillatory Carbonylation Reaction

    Directory of Open Access Journals (Sweden)

    Katarina Novakovic


    Full Text Available Palladium(II iodide is used as a catalyst in the phenylacetylene oxidative carbonylation reaction that has demonstrated oscillatory behaviour in both pH and heat of reaction. In an attempt to extract the reaction network responsible for the oscillatory nature of this reaction, the system was divided into smaller parts and they were studied. This paper focuses on understanding the reaction network responsible for the initial reactions of palladium(II iodide within this oscillatory reaction. The species researched include methanol, palladium(II iodide, potassium iodide, and carbon monoxide. Several chemical reactions were considered and applied in a modelling study. The study revealed the significant role played by traces of water contained in the standard HPLC grade methanol used.

  1. SN2 reactions with allylic substrates--Trends in reactivity (United States)

    Ochran, Richard A.; Uggerud, Einar


    The gas-phase identity SN2 reactions of allylic substrates has been studied by systematic altering of the nucleophile/nucleofuge X, the remote substituent Y, and the number of methyl substituents at the reaction centre: X- + YCHCHCZ2X --> YCHCHCZ2X + X- (X = H, CH3, NH2, F, Cl; Y = F, OH, H, CHO, BH2; Z = H, CH3). Key regions of the potential energy surfaces have been explored by MP2, B3LYP, G3B3 and G3 calculations; the latter two methods providing accurate estimates of the reaction barrier. The calculations show that irrespective of theoretical level, for the second row of the periodic table (X = CH3, NH2, OH, and F), the tendency is that the barrier height decreases in going from left to right in agreement with the previously observed trend for identity SN2 reactions at methyl. The barrier height decreases by introduction a [pi] electron withdrawing substituents, Y, remote 6rom the reaction centre. The barrier height increases by introducing methyl groups (Z = CH3) next to the reaction centre, but the effect is less than half of that of changing the remote substituent from Y = CHO to Y = OH. The trends cannot be explained by simplified valence bond theory and are discussed in light of a simple electrostatic bonding model of the transition structure.

  2. Allyl isothiocyanate induced stress response in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Saini AkalRachna K


    Full Text Available Abstract Background Allyl isothiocyanate (AITC from mustard is cytotoxic; however the mechanism of its toxicity is unknown. We examined the effects of AITC on heat shock protein (HSP 70 expression in Caenorhabditis elegans. We also examined factors affecting the production of AITC from its precursor, sinigrin, a glucosinolate, in ground Brassica juncea cv. Vulcan seed as mustard has some potential as a biopesticide. Findings An assay to determine the concentration of AITC in ground mustard seed was improved to allow the measurement of AITC release in the first minutes after exposure of ground mustard seed to water. Using this assay, we determined that temperatures above 67°C decreased sinigrin conversion to AITC in hydrated ground B. juncea seed. A pH near 6.0 was found to be necessary for AITC release. RT-qPCR revealed no significant change in HSP70A mRNA expression at low concentrations of AITC ( 1.0 μM resulted in a four- to five-fold increase in expression. A HSP70 ELISA showed that AITC toxicity in C. elegans was ameliorated by the presence of ground seed from low sinigrin B. juncea cv. Arrid. Conclusions • AITC induced toxicity in C. elegans, as measured by HSP70 expression. • Conditions required for the conversion of sinigrin to AITC in ground B. juncea seed were determined. • The use of C. elegans as a bioassay to test AITC or mustard biopesticide efficacy is discussed.

  3. Differential inhibition of cytochromes P450 3A4 and 3A5 by the newly synthesized coumarin derivatives 7-coumarin propargyl ether and 7-(4-trifluoromethyl)coumarin propargyl ether. (United States)

    Sridar, Chitra; Kent, Ute M; Noon, Kate; McCall, Alecia; Alworth, Bill; Foroozesh, Maryam; Hollenberg, Paul F


    The abilities of 7-coumarin propargyl ether (CPE) and 7-(4-trifluoromethyl)coumarin propargyl ether (TFCPE) to act as mechanism-based inactivators of P450 3A4 and 3A5 in the reconstituted system have been investigated using 7-benzyloxy-4-(trifluoromethyl)coumarin (BFC) and testosterone as probes. CPE inhibited the BFC O-debenzylation activity of P450 3A4 in a time-, concentration-, and NADPH-dependent manner characteristic of a mechanism-based inactivator with a half-maximal inactivation (K(I)) of 112 microM, a maximal rate of inactivation (k(inact)) of 0.05 min(-1), and a t(1/2) of 13.9 min. Similarly, TFCPE inhibited the BFC O-debenzylation activity of P450 3A4 in a time-, concentration-, and NADPH-dependent manner with a K(I) of 14 microM, a k(inact) of 0.04 min(-1), and a t(1/2) of 16.5 min. Parallel losses of P450 3A4 enzymatic activity and heme were observed with both compounds as measured by high-performance liquid chromatography and reduced CO spectra. Interestingly, neither compound inhibited the BFC O-debenzylation activity of P450 3A5. Reactive intermediates of CPE and TFCPE formed by P450 3A4 were trapped with glutathione, and the resulting adducts were identified using tandem mass spectral analysis. Metabolism studies using TFCPE resulted in the identification of a single metabolite that is formed by P450 3A4 but not by P450 3A5 and that may play a role in the mechanism-based inactivation.

  4. Monomers for thermosetting and toughening epoxy resins. [glycidyl amine derivatives, propargyl-containing amines, and mutagenic testing of aromatic diamines (United States)

    Pratt, J. R.


    Eight glycidyl amines were prepared by alkylating the parent amine with epichlorohydrin to form chlorohydrin, followed by cyclization with aqueous NaOH. Three of these compounds contained propargyl groups with postcuring studies. A procedure for quantitatively estimating the epoxy content of these glycidyl amines was employed for purity determination. Two diamond carbonates and several model propargly compounds were prepared. The synthesis of three new diamines, two which contain propargyloxy groups, and another with a sec-butyl group is in progress. These materials are at the dinitro stage ready for the final hydrogenation step. Four aromatic diamines were synthesized for mutagenic testing purposes. One of these compounds rapidly decomposes on exposure to air.

  5. Electronic spectrum and photodissociation chemistry of the linear methyl propargyl cation H2C4H3+ (United States)

    Catani, Katherine J.; Muller, Giel; da Silva, Gabriel; Bieske, Evan J.


    The electronic spectrum of the methyl propargyl cation (2-butyn-1-yl cation, H2C4H3+) is measured over the 230-270 nm range by photodissociating the bare cation and its Ar and N2 tagged complexes in a tandem mass spectrometer. The observed '1A←'1A band system has an origin at 37 753 cm-1 for H2C4H3+ , 37738 cm-1 for H2C4H3+ - Ar, and 37 658 cm-1 for H2C4H3+ - N2. The methyl propargyl cation photodissociates to produce either C2H3++C2H2 (protonated acetylene + acetylene) or H2C4H+ +H2 (protonated diacetylene + dihydrogen). Photodissociation spectra of H2C4H3+ , H2C4H3+ - Ar, and H2C4H3+ - N2 exhibit similar vibronic structure, with a strong progression of spacing 630 cm-1 corresponding to excitation of the C—C stretch mode. Interpretation of the spectra is aided by ground and excited state calculations using time dependent density functional theory at the ωB97X-D/aug-cc-pVDZ level of theory. Ab initio calculations and master equation simulations were used to interpret the dissociation of H2C4H3+ on the ground state manifold. These calculations support the experimentally observed product branching ratios in which acetylene elimination dominates and also suggests that channel switching occurs at higher energies to favor H2 elimination.

  6. High throughput assay for evaluation of reactive carbonyl scavenging capacity

    Directory of Open Access Journals (Sweden)

    N. Vidal


    Full Text Available Many carbonyl species from either lipid peroxidation or glycoxidation are extremely reactive and can disrupt the function of proteins and enzymes. 4-hydroxynonenal and methylglyoxal are the most abundant and toxic lipid-derived reactive carbonyl species. The presence of these toxics leads to carbonyl stress and cause a significant amount of macromolecular damages in several diseases. Much evidence indicates trapping of reactive carbonyl intermediates may be a useful strategy for inhibiting or decreasing carbonyl stress-associated pathologies. There is no rapid and convenient analytical method available for the assessment of direct carbonyl scavenging capacity, and a very limited number of carbonyl scavengers have been identified to date, their therapeutic potential being highlighted only recently. In this context, we have developed a new and rapid sensitive fluorimetric method for the assessment of reactive carbonyl scavengers without involvement glycoxidation systems. Efficacy of various thiol- and non-thiol-carbonyl scavenger pharmacophores was tested both using this screening assay adapted to 96-well microplates and in cultured cells. The scavenging effects on the formation of Advanced Glycation End-product of Bovine Serum Albumin formed with methylglyoxal, 4-hydroxynonenal and glucose-glycated as molecular models were also examined. Low molecular mass thiols with an α-amino-β-mercaptoethane structure showed the highest degree of inhibitory activity toward both α,β-unsaturated aldehydes and dicarbonyls. Cysteine and cysteamine have the best scavenging ability toward methylglyoxal. WR-1065 which is currently approved for clinical use as a protective agent against radiation and renal toxicity was identified as the best inhibitor of 4-hydroxynonenal.

  7. La synthèse et l'évaluation cytotoxicité de dérivées triazolic contre des lignes de cellule de mélanome B16 et une méthodologie étudient sur la synthèse d'éthers propargyl de leur correspondance propargyl des esters sans catalyseur et sous des irradiations à micro-ondes


    Kalhor Monfared, Shiva,


    Medicinal chemistry is the application of chemical research techniques to the synthesis of pharmaceuticals. During this PhD project, we tried to synthesize small molecules based on terminal alkyne and propargyl alcohols. These molecules were prepared by departing from a simple aldehyde and by doing reactions like Bestmann-Ohira in order to prepare terminal alkynes or reaction with ethynylmagnesium bromide to prepare propargyl alcoholsB. These prepared small molecules were then subjected into ...

  8. 16th Carbonyl Metabolism Meeting: from enzymology to genomics

    Directory of Open Access Journals (Sweden)

    Maser Edmund


    Full Text Available Abstract The 16th International Meeting on the Enzymology and Molecular Biology of Carbonyl Metabolism, Castle of Ploen (Schleswig-Holstein, Germany, July 10–15, 2012, covered all aspects of NAD(P-dependent oxido-reductases that are involved in the general metabolism of xenobiotic and physiological carbonyl compounds. Starting 30 years ago with enzyme purification, structure elucidation and enzyme kinetics, the Carbonyl Society members have meanwhile established internationally recognized enzyme nomenclature systems and now consider aspects of enzyme genomics and enzyme evolution along with their roles in diseases. The 16th international meeting included lectures from international speakers from all over the world.

  9. A New HPLC Method to Determine Carbonyl Compounds in Air

    Institute of Scientific and Technical Information of China (English)


    In this paper, a new HPLC method was established to determine the carbonyl compounds in air. As the absorbent, 2, 4-dinitrophenylhydrazine (2, 4-DNPH) reacted with carbonyls specifically, which form the corresponding 2,4-dinitrophenylhydrazones, then analyzed by HPLC. The chromatographic conditions, the recovery rate, stability of samples, reagent blank, sampling efficiency were all studied systematically. The results showed that this established method had high sensitivity and good selectivity compared with other analytical methods, and it can determine ten carbonyl compounds in air in 26 min simultaneously.

  10. Catalyst-Free Imidation of Allyl Sulfides with Chloramine-T and Subsequent [2,3]-Sigmatropic Rearrangement

    Institute of Scientific and Technical Information of China (English)

    江玉波; 莫凡洋; 邱迪; 匡春香; 张艳; 王剑波


    A facile synthesis of various allyl sulfonamides based on imidation of allyl sulfides with chloramine-T and sub- sequent [2,3]-sigmatropic rearrangement has been achieved without metal catalysts. The reaction completes smoothly within 10 min, providing excellent yields in environment friendly solvent of alcohol. Functional groups such as bromine, hydroxyl, protected amido and aldehyde are tolerant under this condition.

  11. An Efficient Synthesis of de novo Imidates via Aza-Claisen Rearrangements of N-Allyl Ynamides. (United States)

    Dekorver, Kyle A; North, Troy D; Hsung, Richard P


    A novel thermal 3-aza-Claisen rearrangement of N-allyl ynamides for the synthesis of α-allyl imidates is described. Also, a sequential aza-Claisen, Pd-catalyzed Overman rearrangement is described for the synthesis of azapine-2-ones.

  12. Allyl isothiocyanate sensitizes TRPV1 to heat stimulation. (United States)

    Alpizar, Yeranddy A; Boonen, Brett; Gees, Maarten; Sanchez, Alicia; Nilius, Bernd; Voets, Thomas; Talavera, Karel


    The powerful plant-derived irritant allyl isothiocyanate (AITC, aka mustard oil) induces hyperalgesia to heat in rodents and humans through mechanisms that are not yet fully understood. It is generally believed that AITC activates the broadly tuned chemosensory cation channel transient receptor potential cation channel subfamily A member 1 (TRPA1), triggering an inflammatory response that sensitizes the heat sensor transient receptor potential cation channel subfamily V member 1 (TRPV1). In the view of recent data demonstrating that AITC can directly activate TRPV1, we here explored the possibility that this compound sensitizes TRPV1 to heat stimulation in a TRPA1-independent manner. Patch-clamp recordings and intracellular Ca(2+) imaging experiments in HEK293T cells over-expressing mouse TRPV1 revealed that the increase in channel activation induced by heating is larger in the presence of AITC than in control conditions. The analysis of the effects of AITC and heat on the current-voltage relationship of TRPV1 indicates that the mechanism of sensitization is based on additive shifts of the voltage dependence of activation towards negative voltages. Finally, intracellular Ca(2+) imaging experiments in mouse sensory neurons isolated from Trpa1 KO mice yielded that AITC enhances the response to heat, specifically in the subpopulation expressing TRPV1. Furthermore, this effect was strongly reduced by the TRPV1 inhibitor capsazepine and virtually absent in neurons isolated from double Trpa1/Trpv1 KO mice. Taken together, these findings demonstrate that TRPV1 is a locus for cross sensitization between AITC and heat in sensory neurons and may help explaining, at least in part, the role of this channel in AITC-induced hyperalgesia to heat.

  13. How phenyl makes a difference: mechanistic insights into the ruthenium( ii )-catalysed isomerisation of allylic alcohols

    KAUST Repository

    Manzini, Simone


    [RuCl(η5-3-phenylindenyl)(PPh3)2] (1) has been shown to be a highly active catalyst for the isomerisation of allylic alcohols to the corresponding ketones. A variety of substrates undergo the transformation, typically with 0.25-0.5 mol% of catalyst at room temperature, outperforming commonly-used complexes such as [RuCl(Cp)(PPh3) 2] and [RuCl(η5-indenyl)(PPh3) 2]. Mechanistic experiments and density functional theory have been employed to investigate the mechanism and understand the effect of catalyst structure on reactivity. These investigations suggest a oxo-π-allyl mechanism is in operation, avoiding intermediate ruthenium hydride complexes and leading to a characteristic 1,3-deuterium shift. Important mechanistic insights from DFT and experiments also allowed for the design of a protocol that expands the scope of the transformation to include primary allylic alcohols. © 2013 The Royal Society of Chemistry.

  14. Deposition of carbonyl sulphide to soils (United States)

    Kluczewski, S. M.; Brown, K. A.; Bel, J. N. B.

    Carbonyl sulphide (COS) is a trace constituent of the atmosphere and is also the main form in which 35S is released from CO 2-cooled nuclear reactors. Measurements of its deposition velocity ( Vg) are therefore important for validating radiological dose models and for interpreting the role of COS in the global S cycle. The Vg of [ 35S]COS to thin layers of several contrasting soils was measured in a through-flow fumigation system. Deposition velocity was not significantly affected by soil type, although deposition to moist soil was significantly greater ( P dried soils, mean values being 5.71 × 10 -6 ms -1 and 3.06 × 10 -6 ms -1, respectively. The results obtained are about three orders of magnitude smaller than published Vg values for SO 2 to similar soils, which suggests that uptake by soils is not a major sink for atmospheric COS. The results are consistent with the hypothesis that deposition to soil of [ 35S]COS from nuclear reactors is unlikely to contribute significantly to radiation dose from the food chain pathway. The reduction in Vg observed in heat-treated soils indicates a microbial involvement in uptake. However, it seems unlikely that microbial metabolism is the rate-controlling step, since stimulation of the microflora by the addition of nutrients did not increase COS deposition.

  15. CuAAC click chemistry with N-propargyl 1,5-dideoxy-1,5-imino-D-gulitol and N-propargyl 1,6-dideoxy-1,6-imino-D-mannitol provides access to triazole-linked piperidine and azepane pseudo-disaccharide iminosugars displaying glycosidase inhibitory properties. (United States)

    Zamoner, Luís Otávio B; Aragão-Leoneti, Valquíria; Mantoani, Susimaire P; Rugen, Michael D; Nepogodiev, Sergey A; Field, Robert A; Carvalho, Ivone


    Protecting group-free synthesis of 1,2:5,6-di-anhydro-D-mannitol, followed by ring opening with propargylamine and subsequent ring closure produced a separable mix of piperidine N-propargyl 1,5-dideoxy-1,5-imino-D-gulitol and azepane N-propargyl 1,6-dideoxy-1,6-imino-D-mannitol. In O-acetylated form, these two building blocks were subjected to CuAAC click chemistry with a panel of three differently azide-substituted glucose building blocks, producing iminosugar pseudo-disaccharides in good yield. The overall panel of eight compounds, plus 1-deoxynojirimycin (DNJ) as a benchmark, was evaluated as prospective inhibitors of almond β-glucosidase, yeast α-glucosidase and barley β-amylase. The iminosugar pseudo-disaccharides showed no inhibitory activity against almond β-glucosidase, while the parent N-propargyl 1,5-dideoxy-1,5-imino-D-gulitol and N-propargyl 1,6-dideoxy-1,6-imino-D-mannitol likewise proved to be inactive against yeast α-glucosidase. Inhibitory activity could be reinstated in the former series by appropriate substitution on nitrogen. The greater activity of the piperidine could be rationalized based on docking studies. Further, potent inhibition of β-amylase was observed with compounds from both the piperidine and azepane series.

  16. Highly selective palladium–benzothiazole carbene-catalyzed allylation of active methylene compounds under neutral conditions

    Directory of Open Access Journals (Sweden)

    Antonio Monopoli


    Full Text Available The Pd–benzothiazol-2-ylidene complex I was found to be a chemoselective catalyst for the Tsuji–Trost allylation of active methylene compounds carried out under neutral conditions and using carbonates as allylating agents. The proposed protocol consists in a simplified procedure adopting an in situ prepared catalyst from Pd2dba3 and 3-methylbenzothiazolium salt V as precursors. A comparison of the performance of benzothiazole carbene with phosphanes and an analogous imidazolium carbene ligand is also proposed.

  17. Chemoselective and stereoselective lithium carbenoid mediated cyclopropanation of acyclic allylic alcohols. (United States)

    Durán-Peña, M J; Flores-Giubi, M E; Botubol-Ares, J M; Harwood, L M; Collado, I G; Macías-Sánchez, A J; Hernández-Galán, R


    The reaction of geraniol with different lithium carbenoids generated from n-BuLi and the corresponding dihaloalkane has been evaluated. The reaction occurs in a chemo and stereoselective manner, which is consistent with a directing effect from the oxygen of the allylic moiety. Furthermore, a set of polyenes containing allylic hydroxyl or ether groups were chemoselectively and stereoselectively converted into the corresponding gem-dimethylcyclopropanes in one single step in moderate to good yields mediated by a lithium carbenoid generated in situ by the reaction of n-BuLi and 2,2-dibromopropane.

  18. Additive-Free Pd-Catalyzed α-Allylation of Imine-Containing Heterocycles. (United States)

    Kljajic, Marko; Puschnig, Johannes G; Weber, Hansjörg; Breinbauer, Rolf


    An additive-free Pd-catalyzed α-allylation of different imino-group-ontaining heterocycles is reported. The activation of α-CH pronucleophiles (pKa (DMSO) > 25) occurs without the addition of strong bases or Lewis acids using only the Pd/Xantphos catalyst system. The reaction scope has been studied for various 5- and 6-membered nitrogen-containing heterocycles (yields up to 96%). Mechanistic investigations suggest an initial allylation of the imine-N followed by a Pd-catalyzed formal aza-Claisen rearrangement.

  19. Transient overexpression of adh8a increases allyl alcohol toxicity in zebrafish embryos.

    Directory of Open Access Journals (Sweden)

    Nils Klüver

    Full Text Available Fish embryos are widely used as an alternative model to study toxicity in vertebrates. Due to their complexity, embryos are believed to more resemble an adult organism than in vitro cellular models. However, concerns have been raised with respect to the embryo's metabolic capacity. We recently identified allyl alcohol, an industrial chemical, to be several orders of magnitude less toxic to zebrafish embryo than to adult zebrafish (embryo LC50 = 478 mg/L vs. fish LC50 = 0.28 mg/L. Reports on mammals have indicated that allyl alcohol requires activation by alcohol dehydrogenases (Adh to form the highly reactive and toxic metabolite acrolein, which shows similar toxicity in zebrafish embryos and adults. To identify if a limited metabolic capacity of embryos indeed can explain the low allyl alcohol sensitivity of zebrafish embryos, we compared the mRNA expression levels of Adh isoenzymes (adh5, adh8a, adh8b and adhfe1 during embryo development to that in adult fish. The greatest difference between embryo and adult fish was found for adh8a and adh8b expression. Therefore, we hypothesized that these genes might be required for allyl alcohol activation. Microinjection of adh8a, but not adh8b mRNA led to a significant increase of allyl alcohol toxicity in embryos similar to levels reported for adults (LC50 = 0.42 mg/L in adh8a mRNA-injected embryos. Furthermore, GC/MS analysis of adh8a-injected embryos indicated a significant decline of internal allyl alcohol concentrations from 0.23-58 ng/embryo to levels below the limit of detection (< 4.6 µg/L. Injection of neither adh8b nor gfp mRNA had an impact on internal allyl alcohol levels supporting that the increased allyl alcohol toxicity was mediated by an increase in its metabolization. These results underline the necessity to critically consider metabolic activation in the zebrafish embryo. As demonstrated here, mRNA injection is one useful approach to study the role of candidate enzymes

  20. Theoretical Estimate of Hydride Affinities of Aromatic Carbonyl Compounds

    Institute of Scientific and Technical Information of China (English)

    AI Teng; ZHU Xiao-Qing; CHENG Jin-Pei


    @@ Aromatic carbonyl compounds are one type of the most important organic compounds, and the reductions ofthem by hydride agents such as LiAlH4 or NaBH4 are widely used in organic synthesis. The reactivity of carbonyl compounds generally increases in the following order: ketone < aldehyde, and amide < acid < ester < acid halide, which could be related to their hydride affinities (HA). In the previous paper, Robert[1] calculated the absolute HAof a series of small non-aromatic carbonyl compounds. In this paper, we use DFT method at B3LYP/6-311 + + G (2d, 2p)∥B3LYP/6-31 + G* level to estimate hydride affinities of five groups of aromatic carbonyl compounds. The detailed results are listed in Table 1.

  1. Carbonyl-Olefin Exchange Reaction and Related Chemistry (United States)

    Jossifov, Christo; Kalinova, Radostina

    A new carbon—carbon double bond forming reaction (carbonyl olefin exchange reaction) mediated by transition metal catalytic systems has been discovered. The catalytic systems used (transition metal halides or oxohalides alone or in combination with Lewis acids) are active only in the case when the two reacting groups are in one molecules and are conjugated. In addition these systems accelerate other reactions which run simultaneously with the carbonyl olefin metathesis rendering a detailed investigation of the process very complicated.

  2. DNA damage by carbonyl stress in human skin cells

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Michael J.; Wondrak, Georg T.; Laurean, Daniel Cervantes; Jacobson, Myron K.; Jacobson, Elaine L


    Reactive carbonyl species (RCS) are potent mediators of cellular carbonyl stress originating from endogenous chemical processes such as lipid peroxidation and glycation. Skin deterioration as observed in photoaging and diabetes has been linked to accumulative protein damage from glycation, but the effects of carbonyl stress on skin cell genomic integrity are ill defined. In this study, the genotoxic effects of acute carbonyl stress on HaCaT keratinocytes and CF3 fibroblasts were assessed. Administration of the {alpha}-dicarbonyl compounds glyoxal and methylglyoxal as physiologically relevant RCS inhibited skin cell proliferation, led to intra-cellular protein glycation as evidenced by the accumulation of N{sup {epsilon}}-(carboxymethyl)-L-lysine (CML) in histones, and caused extensive DNA strand cleavage as assessed by the comet assay. These effects were prevented by treatment with the carbonyl scavenger D-penicillamine. Both glyoxal and methylglyoxal damaged DNA in intact cells. Glyoxal caused DNA strand breaks while methylglyoxal produced extensive DNA-protein cross-linking as evidenced by pronounced nuclear condensation and total suppression of comet formation. Glycation by glyoxal and methylglyoxal resulted in histone cross-linking in vitro and induced oxygen-dependent cleavage of plasmid DNA, which was partly suppressed by the hydroxyl scavenger mannitol. We suggest that a chemical mechanism of cellular DNA damage by carbonyl stress occurs in which histone glycoxidation is followed by reactive oxygen induced DNA stand breaks. The genotoxic potential of RCS in cultured skin cells and its suppression by a carbonyl scavenger as described in this study have implications for skin damage and carcinogenesis and its prevention by agents selective for carbonyl stress.

  3. Carbonyl species characteristics during the evaporation of essential oils (United States)

    Chiang, Hsiu-Mei; Chiu, Hua-Hsien; Lai, Yen-Ming; Chen, Ching-Yen; Chiang, Hung-Lung


    Carbonyls emitted from essential oils can affect the air quality when they are used in indoors, especially under poor ventilation conditions. Lavender, lemon, rose, rosemary, and tea tree oils were selected as typical and popular essential oils to investigate in terms of composition, thermal characteristics and fifteen carbonyl constituents. Based on thermogravimetric (TG) analysis, the activation energy was 7.6-8.3 kcal mol -1, the reaction order was in the range of 0.6-0.7 and the frequency factor was 360-2838 min -1. Formaldehyde, acetaldehyde, acetone, and propionaldehyde were the dominant carbonyl compounds, and their concentrations were 0.034-0.170 ppm. The emission factors of carbonyl compounds were 2.10-3.70 mg g -1, and acetone, propionaldehyde, acetaldehyde, and formaldehyde accounted for a high portion of the emission factor of carbonyl compounds in essential oil exhaust. Some unhealthy carbonyl species such as formaldehyde and valeraldehyde, were measured at low-temperature during the vaporization of essential oils, indicating a potential effect on indoor air quality and human health.

  4. Detection of the far-IR ν12 bending level in propargyl: a complete set of fundamentals for an important radical. (United States)

    Zhang, Xu; Sander, Stanley P; Stanton, John F


    Propargyl (HCCCH(2)) radicals have been generated by expanding precursors through a supersonic pyrolysis nozzle, and their infrared (IR) absorption spectra have been recorded in a rare gas matrix. Besides the 10 vibrational modes observed in our previous studies, this investigation detected the HCCCH(2) X̃ (2)B(1) in-plane bending mode (ν(12)) at 344.2 (±0.8) cm(-1) in a cryogenic argon matrix. This is the first experimental observation of ν(12) for the propargyl radical. In the previous study, ν(12) had been fixed at 333 (±10) cm(-1) based on detection of its overtone (2ν(12), 667.7 ± 1.0 cm(-1)) and a possible combination band (ν(10) + ν(12), 1339.0 ± 0.8 cm(-1)). The new observation is in reasonable agreement with this previous experimental estimation of ν(12). Ab initio coupled cluster anharmonic force field calculations were used to guide the analysis. Our finding completes the fundamental frequency database for propargyl.

  5. Organocatalytic asymmetric allylic amination of Morita–Baylis–Hillman carbonates of isatins

    Directory of Open Access Journals (Sweden)

    Hang Zhang


    Full Text Available The investigation of a Lewis base catalyzed asymmetric allylic amination of Morita–Baylis–Hillman carbonates derived from isatins afforded an electrophilic pathway to access multifunctional oxindoles bearing a C3-quaternary stereocenter, provided with good to excellent enantioselectivity (up to 94% ee and in high yields (up to 97%.

  6. Polystyrene-supported Selenides and Selenoxide:Versatile Routes to Synthesize Allylic Alcohols

    Institute of Scientific and Technical Information of China (English)

    Wei Ming XU; You Chu ZHANG; Xian HUANG


    Several polystyrene-supported selenides and selenoxide have been prepared firstly. These novel reagents were treated with LDA to produce selenium stabilized carbanions, which reacted with aldehydes and alkyl halides, followed by selenoxide syn-elimination and [2,3] sigmatropic rearrangement respectively to give Z-allylic alcohols stereoselectively.

  7. Method of preparing water purification membranes. [polymerization of allyl amine as thin films in plasma discharge (United States)

    Hollahan, J. R.; Wydeven, T. J., Jr. (Inventor)


    Allyl amine and chemically related compounds are polymerized as thin films in the presence of a plasma discharge. The monomer compound can be polymerized by itself or in the presence of an additive gas to promote polymerization and act as a carrier. The polymerized films thus produced show outstanding advantages when used as reverse osmosis membranes.

  8. Facile Formation of Ytterbium Diiodide and Its Use in the Synthesis of Allyl Selenides

    Institute of Scientific and Technical Information of China (English)

    SU,Wei-Ke(苏为科); ZHANG,Yong-Min(张永敏); ZHENG,Yun-Fa(郑云法); LI,Yong-Shu(李永曙)


    Ytterbium metal reacts with iodine to generate ytterbium diiodide directly, which can react with diselenides to form ytterbium selenolates (RSeYbI2). These species reacted smoothly with allyl bromide to give allylselenides in moderate to good yields under neutral conditions.

  9. Combined experimental and theoretical mechanistic investigation of the Barbier allylation in aqueous media

    DEFF Research Database (Denmark)

    Dam, Johan Hygum; Fristrup, Peter; Madsen, Robert


    -determining step. For Zn, In, Sn, Sb, and Bi, an inverse secondary kinetic isotope effect was found (k(H)/k(D) = 0.75-0.95), which was compatible with the formation of a discrete organometallic species prior to allylation via a closed six-membered transition state. With Mg, a significantly larger build...

  10. Rationalizing Ring-Size Selectivity in Intramolecular Pd-Catalyzed Allylations of Resonance-Stabilized Carbanions

    DEFF Research Database (Denmark)

    Norrby, Per-Ola; Mader, Mary M.; Vitale, Maxime


    Computational methods were applied to the Pd-catalyzed intramolecular allylations of resonance-stabilized carbanions obtained from amide and ketone substrates, with the aim of rationalizing the endo- vs. exo-selectivity in the cyclizations. In addition, ester substrates were prepared and subjecte...

  11. Unusual selectivity-determining factors in the phosphine-free Heck arylation of allyl ethers

    DEFF Research Database (Denmark)

    Ambrogio, I.; Fabrizi, G.; Cacchi, S.


    The Heck reaction of aryl iodides and bromides with allyl ethers has been investigated. Using phosphinefree Pd(OAc)(2) in DNIF at 90 degrees C in the presence of Bu4NOAc, the reaction gave cinnamyl derivatives, usually in good to high yields, with a wide range of aryl halides. The reaction tolera...

  12. Synthesis of allyl esters of fatty acids and their ovicidal effect on Cydia pomonella (L.). (United States)

    Escribà, Marc; Barbut, Montserrat; Eras, Jordi; Canela, Ramon; Avilla, Jesús; Balcells, Mercè


    Eight allyl esters of fatty acids were synthesized in moderate to high yields with a novel two-step procedure using glycerol as a starting material. The two-step methodology avoids the use of allyl alcohol. The first step consisted of heating at 80 degrees C for 48 h a 2:1:5 mmol mixture of glycerol, a fatty acid, and chlorotrimethylsilane in a solvent-free medium. The crude compound was then dissolved in butanone and heated at 115 degrees C in the presence of NaI. A tandem Finkelstein rearrangement-elimination reaction occurs, producing the corresponding allyl ester. The activity of these esters against Cydia pomonella (L.) (Lepidoptera: Tortricidae) eggs was tested in the laboratory by topical application of one 0.1 microL drop. All of the compounds showed a concentration-mortality response and caused 100% mortality at the highest concentration tested (10 mg/mL). There was an inverse relationship between the alkyl chain length and the ovicidal activity of the allyl ester; the LC(50) and the LC(90) of the two compounds that have the longer alkyl chains were significantly higher than those of the rest of the compounds. The ovicidal and IGR activities of this kind of compound appear to be unprecedented.

  13. Zirconium-allyl complexes as resting states in zirconocene-catalyzed α-olefin polymerization. (United States)

    Panchenko, Valentina N; Babushkin, Dmitrii E; Brintzinger, Hans H


    UV-vis spectroscopic data indicate that zirconocene cations with Zr-bound allylic chain ends are generally formed during olefin polymerization with zirconocene catalysts. The rates and extent of their formation and of their re-conversion to the initial pre-catalyst cations depend on the types of zirconocene complexes and activators used.

  14. A Mechanistic Study of Direct Activation of Allylic Alcohols in Palladium Catalyzed Amination Reactions

    NARCIS (Netherlands)

    Gumrukcu, Y.; de Bruin, B.; Reek, J.N.H.


    We here report a computational approach on the mechanism of allylicamination reactions using allyl-alcohols and amines as the substrates and phosphoramidite palladium catalyst 1a, which operates in the presence of catalytic amount of 1,3-diethylurea as a co-catalyst. DFT calculations showed a cooper

  15. Cooperative catalysis by palladium and a chiral phosphoric acid: enantioselective amination of racemic allylic alcohols. (United States)

    Banerjee, Debasis; Junge, Kathrin; Beller, Matthias


    Cooperative catalysis by [Pd(dba)2] and the chiral phosphoric acid BA1 in combination with the phosphoramidite ligand L8 enabled the efficient enantioselective amination of racemic allylic alcohols with a variety of functionalized amines. This catalytic protocol is highly regio- and stereoselective (up to e.r. 96:4) and furnishes valuable chiral amines in almost quantitative yield.

  16. In(OTf)3 catalyzed allylation reaction of imines with tetraallyltin

    Institute of Scientific and Technical Information of China (English)

    Xiao Ning Wei; Ling Yan Liu; Bing Wang; Wei Xing Chang; Jing Li


    In the presence of catalytic amount of In(OTf)3 (10 mol%), a series of aldimines reacted with tetraallyltin in a 2:1 molar ratio to afford the corresponding homoallylic amines in good yields. The good atom efficiency was achieved under mild reaction conditions and a new protocol (allyl)4Sn/In(OTf)3 for simple imines was developed.

  17. Electrochemical studies and self diffusion coefficients in cyclic ammonium based ionic liquids with allyl substituents

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Tzi-Yi [Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan (China); Department of Polymer Materials, Kun Shan University, Tainan 71003, Taiwan (China); Su, Shyh-Gang [Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan (China); Wang, H. Paul [Department of Environmental Engineering, National Cheng Kung University, Tainan, Taiwan (China); Lin, Yuan-Chung [Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Gung, Shr-Tusen; Lin, Ming-Wei [Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan (China); Sun, I.-Wen, E-mail: [Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan (China)


    Research highlights: Cyclic ammonium-based ionic liquids with allyl substituent have high conductivity. Ionic liquids with allyl substituent have wide electrochemical window. Electrochemical and self diffusion coefficients are available for comparison. The Stokes-Einstein plots of DT{sup -1} vs. {eta}{sup -1} for redox couples in ILs are evaluated. Stokes-Einstein product of ferrocene is larger than that of cobaltocenium in ILs. - Abstract: Several cyclic ammonium-based ionic liquids (ILs) with allyl substituent are synthesized, these allyl substituent ILs have high ionic conductivity (up to 4.72 mS cm{sup -1} at 30 {sup o}C) and wide electrochemical window of 5 V. The electrochemical behaviors of two organometallic redox couples Fc/Fc{sup +} (ferrocene/ferrocenium) and Cc/Cc{sup +} (cobaltocene/cobaltocenium) have been studied in these ILs, the calculated Stokes-Einstein product (D{eta} T{sup -1}) of ferrocene in ILs is larger than that of cobaltocenium in ILs. The self-diffusion coefficients of cation and anion in these ILs are studied using pulsed gradient spin-echo NMR technique. There are very few reports where electrochemically derived diffusion coefficients and self diffusion coefficients are available for comparison, so a new key concept in electrochemistry could be developed in this paper.

  18. Palladium-catalyzed cross-coupling reactions of allylic halides and acetates with indium organometallics. (United States)

    Rodríguez, David; Pérez Sestelo, José; Sarandeses, Luis A


    The palladium(0)-catalyzed cross-coupling reaction of allylic halides and acetates with indium organometallics is reported. In this synthetic transformation, triorganoindium compounds and tetraorganoindates (aryl, alkenyl, and methyl) react with cinnamyl and geranyl halides and acetates to afford the S(N)2 product regioselectively and in good yield. The reaction proceeds with net inversion of the stereochemical configuration.

  19. Enantioconvergent synthesis by sequential asymmetric Horner-Wadsworth-Emmons and palladium-catalyzed allylic substitution reactions

    DEFF Research Database (Denmark)

    Pedersen, Torben Møller; Hansen, E. Louise; Kane, John


    A new method for enantioconvergent synthesis has been developed. The strategy relies on the combination of an asymmetric Horner-Wadsworth-Emmons (HWE) reaction and a palladium-catalyzed allylic substitution. Different $alpha@-oxygen-substituted, racemic aldehydes were initially transformed...

  20. [N-allyl-Dmt1]-endomorphins are micro-opioid receptor antagonists lacking inverse agonist properties. (United States)

    Marczak, Ewa D; Jinsmaa, Yunden; Li, Tingyou; Bryant, Sharon D; Tsuda, Yuko; Okada, Yoshio; Lazarus, Lawrence H


    [N-allyl-Dmt1]-endomorphin-1 and -2 ([N-allyl-Dmt1]-EM-1 and -2) are new selective micro-opioid receptor antagonists obtained by N-alkylation with an allyl group on the amino terminus of 2',6'-dimethyl-L-tyrosine (Dmt) derivatives. To further characterize properties of these compounds, their intrinsic activities were assessed by functional guanosine 5'-O-(3-[35S]thiotriphosphate) binding assays and forskolin-stimulated cyclic AMP accumulation in cell membranes obtained from vehicle, morphine, and ethanol-treated SK-N-SH cells and brain membranes isolated from naive and morphine-dependent mice; their mode of action was compared with naloxone or naltrexone, which both are standard nonspecific opioid-receptor antagonists. [N-allyl-Dmt1]-EM-1 and -2 were neutral antagonists under all of the experimental conditions examined, in contrast to naloxone and naltrexone, which behave as neutral antagonists only in membranes from vehicle-treated cells and mice but act as inverse agonists in membranes from morphine- and ethanol-treated cells as well as morphine-treated mice. Both endomorphin analogs inhibited the naloxone- and naltrexone-elicited withdrawal syndromes from acute morphine dependence in mice. This suggests their potential therapeutic application in the treatment of drug addiction and alcohol abuse without the adverse effects observed with inverse agonist alkaloid-derived compounds that produce severe withdrawal symptoms.

  1. Surprisingly Mild Enolate-Counterion-Free Pd(0)-Catalyzed Intramolecular Allylic Alkylations

    DEFF Research Database (Denmark)

    Madec, David; Prestat, Guillaume; Martini, Elisabetta;


    Palladium-catalyzed intramolecular allylic alkylations of unsaturated EWG-activated amides can take place under phase-transfer conditions or in the presence of a crown ether. These new reaction conditions are milder and higher yielding than those previously reported. A rationalization for such an...

  2. A Novel, One-Step Palladium and Phenylsilane Activated Amidation from Allyl Ester on Solid Support

    Directory of Open Access Journals (Sweden)

    Zheming Ruan


    Full Text Available The direct conversion of solid-supported carboxylic acid allyl esters to carboxamides through the use of phenylsilane and catalytic Pd(PPh34 under mild reaction conditions is reported. The use of this methodology for the generation of a 48 compound solid-phase array is described herein.

  3. Catalytic allylation of phenols : chloride-free route towards epoxy resins

    NARCIS (Netherlands)

    Rijn, Jimmy Antonius van


    An industrially applicable process was developed for the synthesis of epoxy resin components. A catalytic reaction was explored towards allyl phenyl ethers that prevents the use of chloride-containing starting materials and thus formation of chloride-containing side products. The preferred allylatin

  4. Copper-catalyzed asymmetric allylic substitution reactions with organozinc and Grignard reagents

    NARCIS (Netherlands)

    Geurts, Koen; Fletcher, Stephen P.; van Zijl, Anthoni W.; Minnaard, Adriaan J.; Feringa, Ben L.; Bignall, H. E.; Jauncey, D. L.; Lovell, J. E. J.; Tzioumis, A. K.; Kedziora-Chudczer, L. L.; MacQuart, J. P.; Tingay, S. J.; Rayner, D. P.; Clay, R. W.


    Asymmetric allylic alkylations (AAAs) are among the most powerful C-C bond-forming reactions. We present a brief overview of copper-catalyzed AAAs with organometallic reagents and discuss our own contributions to this field. Work with zinc reagents and phosphoramidite ligands provided a framework fo

  5. Synthesis, Characterization, and Some Properties of Cp*W(NO)(H)(η(3)-allyl) Complexes. (United States)

    Baillie, Rhett A; Holmes, Aaron S; Lefèvre, Guillaume P; Patrick, Brian O; Shree, Monica V; Wakeham, Russell J; Legzdins, Peter; Rosenfeld, Devon C


    Sequential treatment at low temperatures of Cp*W(NO)Cl2 in THF with 1 equiv of a binary magnesium allyl reagent, followed by an excess of LiBH4, affords three new Cp*W(NO)(H)(η(3)-allyl) complexes, namely, Cp*W(NO)(H)(η(3)-CH2CHCMe2) (1), Cp*W(NO)(H)(η(3)-CH2CHCHPh) (2), and Cp*W(NO)(H)(η(3)-CH2CHCHMe) (3). Complexes 1-3 are isolable as air-stable, analytically pure yellow solids in good to moderate yields by chromatography or fractional crystallization. In solutions, complex 1 exists as two coordination isomers in an 83:17 ratio differing with respect to the endo/exo orientation of the allyl ligand. In contrast, complexes 2 and 3 each exist as four coordination isomers, all differing by the orientation of their allyl ligands which can have either an endo or an exo orientation with the phenyl or methyl groups being either proximal or distal to the nitrosyl ligand. A DFT computational analysis using the major isomer of Cp*W(NO)(H)(η(3)-CH2CHCHMe) (3a) as the model complex has revealed that its lowest-energy thermal-decomposition pathway involves the intramolecular isomerization of 3a to the 16e η(2)-alkene complex, Cp*W(NO)(η(2)-CH2═CHCH2Me). Such η(2)-alkene complexes are isolable as their 18e PMe3 adducts when compounds 1-3 are thermolyzed in neat PMe3, the other organometallic products formed during these thermolyses being Cp*W(NO)(PMe3)2 (5) and, occasionally, Cp*W(NO)(H)(η(1)-allyl)(PMe3). All new complexes have been characterized by conventional spectroscopic and analytical methods, and the solid-state molecular structures of most of them have been established by single-crystal X-ray crystallographic analyses.

  6. The Wacker oxidation of allyl alcohol along cyclic-intermediate routes: An ab initio molecular dynamics investigation (United States)

    Imandi, Venkataramana; Nair, Nisanth N.


    The absence of isotope scrambling observed by Henry and coworkers in the Wacker oxidation of deuterated allylic alcohol was used by them as support for the inner-sphere mechanism hydroxypalladation mechanism. One of the assumptions used to interpret their experimental data was that allyl alcohol oxidation takes place through non-cyclic intermediate routes as in the case of ethene. Here we verify this assumption through ab initio metadynamics simulations of the Wacker oxidation of allyl alcohol in explicit solvent. Importance of our results in interpreting the isotope scrambling experiments is discussed.

  7. Deconvoluting the memory effect in Pd-catalyzed allylic alkylation; effect of leaving group and added chloride

    DEFF Research Database (Denmark)

    Fristrup, Peter; Jensen, Thomas; Hoppe, Jakob;


    An analysis of product distributions in the Tsuji-Trost reaction indicates that several instances of reported memory effects can be attributed to slow interconversion of the initially formed syn- and anti-[Pd(eta3-allyl)] complexes. Addition of chloride triggers a true memory effect, in which...... the allylic terminus originally bearing the leaving group has a higher reactivity. The latter effect, termed regioretention, can be rationalized by ionization from a palladium complex bearing a chloride ion, forming an unsymmetrically substituted [Pd(eta3-allyl)] complex. DFT calculations verify...

  8. Determination of Carbonyl Compounds in Exhaled Cigarette Smoke

    Directory of Open Access Journals (Sweden)

    Moldoveanu S


    Full Text Available This paper presents the findings on a quantitative evaluation of carbonyl levels in exhaled cigarette smoke from human subjects. The cigarettes evaluated include products with 5.0 mg ‘tar’, 10.6 mg ‘tar’ and 16.2 mg ‘tar’, where ‘tar’ is defined as the weight of total wet particulate matter (TPM minus the weight of nicotine and water, and the cigarettes are smoked following U.S. Federal Trade Commission (FTC recommendations. The measured levels of carbonyls in the exhaled smoke were compared with calculated yields of carbonyls in the inhaled smoke and a retention efficiency was obtained. The number of human subjects included a total of ten smokers for the 10.6 mg ‘tar’, five for the 16.2 mg ‘tar’, and five for the 5.0 mg ‘tar’ product, each subject smoking three cigarettes. The analyzed carbonyl compounds included several aldehydes (formaldehyde, acetaldehyde, acrolein, propionaldehyde, crotonaldehyde and n-butyraldehyde, and two ketones (acetone and 2-butanone. The smoke collection from the human subjects was vacuum assisted. Exhaled smoke was collected on Cambridge pads pretreated with a solution of dinitrophenylhydrazine (DNPH followed by high performance liquid chromatography (HPLC analysis of the dinitrophenylhydrazones of the carbonyl compounds. The cigarette butts from the smokers were collected and analyzed for nicotine. The nicotine levels for the cigarette butts from the smokers were used to calculate the level of carbonyls in the inhaled smoke, based on calibration curves. These were generated separately by analyzing the carbonyls in smoke and the nicotine in the cigarette butts obtained by machine smoking under different puffing regimes. The comparison of the level of carbonyl compounds in exhaled smoke with that from the inhaled smoke showed high retention of all the carbonyls. The retention of aldehydes was above 95% for all three different ‘tar’ levels cigarettes. The ketones were retained with a

  9. New methodology for removing carbonyl compounds from sweet wines. (United States)

    Blasi, Mélanie; Barbe, Jean-Christophe; Maillard, Bernard; Dubourdieu, Denis; Deleuze, Hervé


    Sweet white wines from botrytized grapes present high SO2 levels because of their high sulfur dioxide binding power. The objective of this work was to develop a new method for reducing this binding power by partially eliminating the carbonyl compounds naturally present in these wines that are responsible for this phenomenon. A selective liquid-solid removal technique was developed. Phenylsulfonylhydrazine was selected as the best candidate for removing carbonyl compounds. Its reactivity in the presence or absence of sulfur dioxide was verified in model media containing acetaldehyde, pyruvic acid, and 2-oxoglutaric acid, some of the main carbonyl compounds responsible for the SO2 binding power of sweet wines. The scavenging function was grafted on porous polymer supports, and its efficiency was evaluated in model wines. Dependent upon the supports used, different quantities of carbonyl compounds (over 90% in some cases) were removed in a few days. The presence of sulfur dioxide delayed removal without changing its quality. The results obtained showed that the method removed carbonyl compounds efficiently and was applicable to wines at any stage in winemaking.

  10. Highly efficient redox isomerisation of allylic alcohols catalysed by pyrazole-based ruthenium(IV) complexes in water: mechanisms of bifunctional catalysis in water. (United States)

    Bellarosa, Luca; Díez, Josefina; Gimeno, José; Lledós, Agustí; Suárez, Francisco J; Ujaque, Gregori; Vicent, Cristian


    The catalytic activity of ruthenium(IV) ([Ru(η(3):η(3)-C(10)H(16))Cl(2)L]; C(10)H(16) = 2,7-dimethylocta-2,6-diene-1,8-diyl, L = pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole, 3-methyl-5-phenylpyrazole, 2-(1H-pyrazol-3-yl)phenol or indazole) and ruthenium(II) complexes ([Ru(η(6)-arene)Cl(2)(3,5-dimethylpyrazole)]; arene = C(6)H(6), p-cymene or C(6)Me(6)) in the redox isomerisation of allylic alcohols into carbonyl compounds in water is reported. The former show much higher catalytic activity than ruthenium(II) complexes. In particular, a variety of allylic alcohols have been quantitatively isomerised by using [Ru(η(3):η(3)-C(10)H(16))Cl(2)(pyrazole)] as a catalyst; the reactions proceeded faster in water than in THF, and in the absence of base. The isomerisations of monosubstituted alcohols take place rapidly (10-60 min, turn-over frequency = 750-3000 h(-1)) and, in some cases, at 35 °C in 60 min. The nature of the aqueous species formed in water by this complex has been analysed by ESI-MS. To analyse how an aqueous medium can influence the mechanism of the bifunctional catalytic process, DFT calculations (B3LYP) including one or two explicit water molecules and using the polarisable continuum model have been carried out and provide a valuable insight into the role of water on the activity of the bifunctional catalyst. Several mechanisms have been considered and imply the formation of aqua complexes and their deprotonated species generated from [Ru(η(3):η(3)-C(10)H(16))Cl(2)(pyrazole)]. Different competitive pathways based on outer-sphere mechanisms, which imply hydrogen-transfer processes, have been analysed. The overall isomerisation implies two hydrogen-transfer steps from the substrate to the catalyst and subsequent transfer back to the substrate. In addition to the conventional Noyori outer-sphere mechanism, which involves the pyrazolide ligand, a new mechanism with a hydroxopyrazole complex as the active species can be at work in water. The

  11. The magnesium-ene cyclization stereochemically directed by an allylic oxyanionic group and its application to a highly stereoselective synthesis of (+/-)-matatabiether. Allylmagnesium compounds by reductive magnesiation of allyl phenyl sulfides. (United States)

    Cheng, D; Zhu, S; Yu, Z; Cohen, T


    The first example of a magnesium-ene cyclization stereochemically directed by an allylic oxyanionic group is demonstrated by a highly stereoselective synthesis of the bicyclic terpene matatabiether 10. The synthetic method is particularly valuable, not only because of the stereochemical control and the utility of the versatile hydroxyl group introduced into the product, but also because the precursor of the allylmagnesium is an allyl phenyl sulfide, which is more stable and more easily prepared in a connective fashion than the usual allyl halide precursor. Since the presence of lithium ions encourages undesirable proton transfer to the cyclized organometallic and is detrimental to the stereochemical control, the conversion of the allylic thioether to the allylmagnesium utilizes a lithium-free method involving direct reductive magnesiation in the presence of the magnesium-anthracene complex.

  12. Sub-Doppler infrared spectroscopy of propargyl radical (H{sub 2}CCCH) in a slit supersonic expansion

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chih-Hsuan; Nesbitt, David J. [JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA and Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, Colorado 80309 (United States)


    The acetylenic CH stretch mode (ν{sub 1}) of propargyl (H{sub 2}CCCH) radical has been studied at sub-Doppler resolution (∼60 MHz) via infrared laser absorption spectroscopy in a supersonic slit-jet discharge expansion, where low rotational temperatures (T{sub rot} = 13.5(4) K) and lack of spectral congestion permit improved determination of band origin and rotational constants for the excited state. For the lowest J states primarily populated in the slit jet cooled expansion, fine structure due to the unpaired electron spin is resolved completely, which permits accurate analysis of electron spin-rotation interactions in the vibrationally excited states (ε{sub aa} = − 518.1(1.8), ε{sub bb} = − 13.0(3), ε{sub cc} = − 1.8(3) MHz). In addition, hyperfine broadening in substantial excess of the sub-Doppler experimental linewidths is observed due to nuclear spin–electron spin contributions at the methylenic (—CH{sub 2}) and acetylenic (—CH) positions, which permits detailed modeling of the fine/hyperfine structure line contours. The results are consistent with a delocalized radical spin density extending over both methylenic and acetylenic C atoms, in excellent agreement with simple resonance structures as well as ab initio theoretical calculations.

  13. From the tunneling dimer to the onset of microsolvation: Infrared spectroscopy of allyl radical water aggregates in helium nanodroplets (United States)

    Leicht, Daniel; Kaufmann, Matin; Pal, Nitish; Schwaab, Gerhard; Havenith, Martina


    The infrared spectrum of allyl:water clusters embedded in helium nanodroplets was recorded. Allyl radicals were produced by flash vacuum pyrolysis and trapped in helium droplets. Deuterated water was added to the doped droplets, and the infrared spectrum of the radical water aggregates was recorded in the frequency range 2570-2820 cm-1. Several absorption bands are observed and assigned to 1:1 and 1:2 allyl:D2O clusters, based on pressure dependent measurements and accompanying quantum chemical calculations. The analysis of the 1:1 cluster spectrum revealed a tunneling splitting as well as a combination band. For the 1:2 cluster, we observe a water dimer-like motif that is bound by one π-hydrogen bond to the allyl radical.

  14. Isolation determination of garlic allyl sulfides and their antioxidant activity%大蒜烯丙基硫化物的分离鉴定及抗氧化性

    Institute of Scientific and Technical Information of China (English)

    刘玲; 陈琭璐; 张瑶; 白冰; 纪淑娟


    through comparing the compounds of SAC, ACSO and GSAC with glutathione (GSH) to evaluate the antioxidation. SAC, ACSO and GSAC were isolated from garlic bulbs using ion-exchange chromatography and pre-HPLC (high performance liquid chromatography). Their molecular structures were identified by high performance liquid chromatography-electrospray ionization-mass/mass spectrometry (HPLC-ESI-MS/MS), proton nuclear magnetic resonance (1H NMR), carbon-13 nuclear magnetic resonance (13C NMR) and specific rotatory power. SAC and ACSO which yielded the expected [M+H]+ of m/z 162.1 and 177.8 by the measurement of mass spectrometry under positive ion mode were conferred asS-allyl-L-cysteine (C6H11O2NS) andS-allyl-L-cysteine sulfoxide (C6H11O3NS) respectively compared with the data of corresponding standard. GSAC, showing the corresponding [M-H]- of m/z 288.8, was identified asγ-glutamyl-S-allyl-L-cysteine (C11H18O5N2S) by HPLC-MS. The1H NMR spectrum of SAC and ACSOindicated the presence of the cysteinyl (δ 2.96 and 3.83, 3H) and (δ 3.26 and 4.13, 3H) moieties. The13C NMR spectrum of compound SAC and ACSO showed the presence of the cysteinyl carboxyl (δ 175.6 andδ 188.0) carbons. Similarly, the1H NMR spectrum of GSAC indicated the presence of the glutamyl (δ 2.32-2.43, 2.66 and 3.46, 5H) and cysteinyl (δ 2.75 and 4.76, 3H) moieties. The13C NMR spectrum of GSACrevealed the presence of 11 magnetically nonequivalent carbon atoms, with three of them being the glutamyl carboxyl, glutamyl carbonyl and cysteinyl carboxyl (δ 182.5, 183.2 and 184.4) carbons. Meanwhile, the scavenging activity of DPPH free radical and the chelating activity of iron ion by allyl-substituted sulfides (SAC, ACSO and GSAC) were determined with reference to cysteine derivative of GSH. The scavenging activity of DPPH free radical had no significant difference between GSH (71.14%) and both of SAC (73.55%) andGSAC (72.68%). Iron ion is one of the main oxidizing auxiliaries which can initiate free radical in

  15. Carbonyl Sulfides as Possible Intermediates in the Photolysis of Oxathiiranes

    DEFF Research Database (Denmark)

    Carlsen, Lars; Snyder, J. P.; Holm, A.


    of sulfine to ketone via the oxathiirane and the subsequent blue intermediate implies the absence of triplet and biradical singlet transients. The unknown carbonyl sulfide functionality, R2C&z.dbnd;O&z.dbnd;S, thereby emerges as a strong candidate for producing the visible absorption. Comparison of the wave...... functions for CH2&z.dbnd;S&z.dbnd;O and CH2&z.dbnd;O&z.dbnd;S arising from MNDO limited CI geometry optimizations leads to the conclusion that the carbonyl sulfide structure is best described as a zwitterion rather than as a singlet biradical. The failure to observe cycloaddition products between the blue...

  16. Chemoenzymatic one-pot synthesis in an aqueous medium: combination of metal-catalysed allylic alcohol isomerisation-asymmetric bioamination. (United States)

    Ríos-Lombardía, Nicolás; Vidal, Cristian; Cocina, María; Morís, Francisco; García-Álvarez, Joaquín; González-Sabín, Javier


    The ruthenium-catalysed isomerisation of allylic alcohols was coupled, for the first time, with asymmetric bioamination in a one-pot process in an aqueous medium. In the cases involving prochiral ketones, the ω-TA exhibited excellent enantioselectivity, identical to that observed in the single step. As a result, amines were obtained from allylic alcohols with high overall yields and excellent enantiomeric excesses.

  17. An alternative method for monitoring carbonyls, and the development of a 24-port fully automated carbonyl sampler for PAMS program

    Energy Technology Data Exchange (ETDEWEB)

    Parmar, S.S.; Ugarova, L. [Atmospheric Analysis and Consulting, Ventura, CA (United States); Fernandes, C.; Guyton, J.; Lee, C.P. [Arizona Dept. of Environmental Quality, Phoenix, AZ (United States)


    The authors have investigated the possibility of collecting different aldehydes and ketones on different sorbents such as silica gel, molecular sieve and charcoal followed by solvent extraction, DNPH derivatization and HPLC/UV analysis. Carbonyl collection efficiencies for these sorbents were calculated relative to a DNPH coated C{sub 18} sep-pak cartridge. From a limited number of laboratory experiments, at various concentrations, it appears that silica gel tubes can be used for sampling aldehydes (collection efficiencies {approximately} 1), whereas charcoal tubes are suitable for collecting ketones. Molecular sieve was found to be unsuitable for collecting most of the carbonyl studied. The authors also report the development of a fully automated 24-port carbonyl sampler specially designed for EPA`s PAMS program.

  18. Synthesis, characterization and evaluation of antioxidant and anticancer activities of novel benzisoxazole-substituted-allyl derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Anand, Mohanam [Kingston Engineering College, Vellore (India); Selvaraj, Vaithialingam [University College of Engineering-Villupuram, Villupuram (India); Alagar, Muthukaruppan [Anna University, Chennai (India)


    A novel series of various 2-allylbenzo[d]isoxazol-3(2H)-ones were synthesized using benzo[d]isoxazol-3(2H)-one treated with different allyl bromides/chlorides in the presence of water-mediated cesium carbonate as a new catalyst 3(a-h). The structures of the newly synthesized Benzisoxazole-substituted-allyl derivatives were characterized by spectroscopic methods and mass spectrometry. These synthesized compounds were evaluated for their in vitro antioxidant and anticancer activity. Compounds 3b, d, f, h were identified as the best hit against HT-29 Human colon cancer cells. Similarly, compounds like 3b, d, f, h showed significant antioxidant activity compared to the standard drug butylated hydroxy toluene (BHT)

  19. Recent Advances in the Application of Chiral Phosphine Ligands in Pd-Catalysed Asymmetric Allylic Alkylation

    Directory of Open Access Journals (Sweden)

    Erika Martin


    Full Text Available One of the most powerful approaches for the formation of simple and complex chiral molecules is the metal-catalysed asymmetric allylic alkylation. This reaction has been broadly studied with a great variety of substrates and nucleophiles under different reaction conditions and it has promoted the synthesis of new chiral ligands to be evaluated as asymmetric inductors. Although the mechanism as well as the active species equilibria are known, the performance of the catalytic system depends on the fine tuning of factors such as type of substrate, nucleophile nature, reaction medium, catalytic precursor and type of ligand used. Particularly interesting are chiral phosphines which have proved to be effective asymmetric inductors in several such reactions. The present review covers the application of phosphine-donor ligands in Pd-catalysed asymmetric allylic alkylation in the last decade.

  20. Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso-ene mechanism. (United States)

    Porter, David; Poon, Belinda M-L; Rutledge, Peter J


    Iron(II) complexes of the tetradentate amines tris(2-pyridylmethyl)amine (TPA) and N,N'-bis(2-pyridylmethyl)-N,N'-dimethylethane-1,2-diamine (BPMEN) are established catalysts of C-O bond formation, oxidising hydrocarbon substrates via hydroxylation, epoxidation and dihydroxylation pathways. Herein we report the capacity of these catalysts to promote C-N bond formation, via allylic amination of alkenes. The combination of N-Boc-hydroxylamine with either FeTPA (1 mol %) or FeBPMEN (10 mol %) converts cyclohexene to the allylic hydroxylamine (tert-butyl cyclohex-2-en-1-yl(hydroxy)carbamate) in moderate yields. Spectroscopic studies and trapping experiments suggest the reaction proceeds via a nitroso-ene mechanism, with involvement of a free N-Boc-nitroso intermediate. Asymmetric induction is not observed using the chiral tetramine ligand (+)-(2R,2'R)-1,1'-bis(2-pyridylmethyl)-2,2'-bipyrrolidine ((R,R')-PDP).

  1. [Surface modification of poly methyl methacrylate intraocular lens by alpha-allyl glucoside]. (United States)

    Qu, Chao; Yao, Ke; Kou, Ruiqiang; Xu, Zhikang


    A method for improving the biocompatibility of the intraocular lens (IOL) and reducing the cell attachment was adopted in this study. The alpha-Allyl glucoside was used for the surface modification of the poly methyl methacrylate (PMMA) IOL by way of plasma-induced in situ polymerization. The surfaces of the control and treatment IOLs were characterized by contact angle estimation and ESCA techniques. The resolution, diopter and anti-fatigue of loops were determined by physical and optical methods. Cell attachment on the surfaces was examined by light microscopy. The results indicated that all of the treatment groups had excellent physical and optical properties. The modification with the use of alpha-Allyl glucoside could improve the hydrophilicity of the anterior surface of the PMMA IOLs and reduce the cell attachment.

  2. Epoxidation of allyl alcohol to glycidol over the microporous TS-1 catalyst. (United States)

    Wróblewska, Agnieszka; Fajdek, Anna


    The results of the epoxidation of allyl alcohol with 30% hydrogen peroxide over the TS-1 catalyst have been presented. The studies were carried out under the atmospheric pressure and at the presence of methanol as a solvent. The influence of the following technological parameters on the course of epoxidation was examined: the temperature of 20-60 degrees C, the molar ratio of AA/H(2)O(2) 1:1-5:1, the methanol concentration of 5-90 wt%, the catalyst content of 0.1-5.0 wt% and the reaction time 5-300 min. The main functions describing the process were the selectivity to glycidol in relation to allyl alcohol consumed, the conversion of substrates, and the selectivity of transformation to organic compounds in relation to hydrogen peroxide consumed. The parameters at which the functions describing the process reached the highest values were determined.

  3. Crystal structure of (E-3-allyl-2-sulfanylidene-5-[(thiophen-2-ylmethylidene]thiazolidin-4-one

    Directory of Open Access Journals (Sweden)

    Rahhal El Ajlaoui


    Full Text Available Molecules of the title compound, C11H9NOS3, are built up by one thiophene and one 2-thioxathiazolidin-4-one ring which are connected by a methylene bridge. In addition, there is an allyl substituent attached to nitrogen. The two rings are almost coplanar, making a dihedral angle between them of 0.76 (11°. The allyl group is oriented perpendicular to the mean plane through both ring systems. The crystal structure exhibits inversion dimers in which molecules are linked by pairs of C—H...O hydrogen bonds. Additional π–π interactions between neighboring thiophene and 2-thioxathiazolidin-4-one rings [intercentroid distance = 3.694 (2 Å] lead to the formation of a three-dimensional network.

  4. Synthetic Studies on Tricyclic Diterpenoids: Direct Allylic Amination Reaction of Isopimaric Acid Derivatives. (United States)

    Timoshenko, Mariya A; Kharitonov, Yurii V; Shakirov, Makhmut M; Bagryanskaya, Irina Yu; Shults, Elvira E


    A selective synthesis of 7- or 14-nitrogen containing tricyclic diterpenoids was completed according to a strategy in which the key step was the catalyzed direct allylic amination of methyl 14α-hydroxy-15,16-dihydroisopimarate with a wide variety of nitrogenated nucleophiles. It was revealed that the selectivity of the reaction depends on the nature of nucleophile. The catalyzed reaction of the mentioned diterpenoid allylic alcohol with 3-nitroaniline, 3-(trifluoromethyl)aniline, and 4-(trifluoromethyl)aniline yield the subsequent 7α-, 7β- and 14αnitrogen-containing diterpenoids. The reaction with 2-nitroaniline, 4-nitro-2-chloroaniline, 4-methoxy-2-nitroaniline, phenylsulfamide, or tert-butyl carbamate proceeds with the formation of 7α-nitrogen-substituted diterpenoids as the main products.

  5. Age-related variations of protein carbonyls in human saliva and plasma: is saliva protein carbonyls an alternative biomarker of aging? (United States)

    Wang, Zhihui; Wang, Yanyi; Liu, Hongchen; Che, Yuwei; Xu, Yingying; E, Lingling


    Free radical hypothesis which is one of the most acknowledged aging theories was developed into oxidative stress hypothesis. Protein carbonylation is by far one of the most widely used markers of protein oxidation. We studied the role of age and gender in protein carbonyl content of saliva and plasma among 273 Chinese healthy subjects (137 females and 136 males aged between 20 and 79) and discussed the correlation between protein carbonyl content of saliva and plasma. Protein carbonyl content of saliva and plasma were, respectively, 2.391 ± 0.639 and 0.838 ± 0.274 nmol/mg. Variations of saliva and plasma different age groups all reached significant differences in both male and female (all p saliva and plasma protein carbonyls were found to be significantly correlated with age (r = 0.6582 and r = 0.5176, all p saliva and plasma protein carbonyl levels (all p > 0.05). Saliva and plasma protein carbonyls were positively related (r = 0.4405, p saliva and plasma protein carbonyls/ferric reducing ability of plasma (FRAP) ratios were proved to be significantly correlated with age (r = 0.7796 and r = 0.6938, all p saliva protein carbonyls/FRAP ratio and plasma protein carbonyls/FRAP ratio were also correlated (r = 0.5573, p saliva protein carbonyls seem to be an alternative biomarker of aging while the mechanisms of protein carbonylation and oxidative stress and the relationship between saliva protein carbonyls and diseases need to be further investigated.

  6. Synthesis of alkenyl boronates from allyl-substituted aromatics using an olefin cross-metathesis protocol. (United States)

    Hemelaere, Rémy; Carreaux, François; Carboni, Bertrand


    An efficient synthesis of 3-aryl-1-propenyl boronates from pinacol vinyl boronic ester and allyl-substituted aromatics by cross metathesis is reported. Although the allylbenzene derivatives are prone to isomerization reaction under metathesis conditions, we found that some ruthenium catalysts are effective for this methodology. This strategy thus provides an interesting alternative approach to alkyne hydroboration, leading to the preparation of unknown compounds. Moreover, the boron substituent can be replaced by various functional groups in good yields.

  7. Highly Regioselective Palladium-Catalyzed Carboxylation of Allylic Alcohols with CO2. (United States)

    Mita, Tsuyoshi; Higuchi, Yuki; Sato, Yoshihiro


    Various allylic alcohols were carboxylated in the presence of a catalytic amount of PdCl2 and PPh3 using ZnEt2 as a stoichiometric transmetalation agent under a CO2 atmosphere (1 atm). This carboxylation proceeded in a highly regioselective manner to afford branched carboxylic acids predominantly. The β,γ-unsaturated carboxylic acid thus obtained was successfully converted into an optically active γ-butyrolactone, a known intermediate of (R)-baclofen.

  8. On the key role of water in the allylic activation catalysed by Pd (II) bisphosphinite complexes

    Indian Academy of Sciences (India)

    Rakesh Kumar Sharma; Ashoka G Samuelson


    Palladium and platinum complexes of bisphosphinites and bisphosphines derived from mandelic acid have been prepared and characterized. Their ability to catalyze allylation of imines with allyltributylstannane has been studied. Bisphophinite complexes of Pd (II) are shown to be ideal and they work best in the presence of one equivalent of water. The near neutral conditions employed make the catalysts suitable for a wide variety of substrates.

  9. Lewis base catalyzed enantioselective allylic hydroxylation of Morita-Baylis-Hillman carbonates with water

    KAUST Repository

    Zhu, Bo


    A Lewis base catalyzed allylic hydroxylation of Morita-Baylis-Hillman (MBH) carbonates has been developed. Various chiral MBH alcohols can be synthesized in high yields (up to 99%) and excellent enantioselectivities (up to 94% ee). This is the first report using water as a nucleophile in asymmetric organocatalysis. The nucleophilic role of water has been verified using 18O-labeling experiments. © 2011 American Chemical Society.

  10. Iron(III) chloride catalyzed glycosylation of peracylated sugars with allyl/alkynyl alcohols

    Energy Technology Data Exchange (ETDEWEB)

    Narayanaperumal, Senthil; Silva, Rodrigo Cesar da; Monteiro, Julia L.; Correa, Arlene G.; Paixao, Marcio W., E-mail: [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica


    In this work, the use of ferric chloride as an efficient catalyst in glycosylation reactions of sugars in the presence of allyl and alkynyl alcohols is described. The corresponding glycosides were obtained with moderate to good yields. This new procedure presented greater selectivity when compared to classic methods found in the literature. Principal features of this simple method include non-hazardous reaction conditions, low-catalyst loading, good yields and high anomeric selectivity (author)

  11. α-Carbonyl Radical Cyclizatio n in Organic Synthesis

    Institute of Scientific and Technical Information of China (English)

    SHA Chin-Kang; CHIU Rei-Torng; LIH Shinn-Horng; SANTHOSH K. C.; CHANG Ching-Jung; TSENG Wei-Hong; HO Wen-Yueh


    @@ Intramolecular radical cyclization reactions are now used routinely to synthesize carbocyclic and heterocyclic structures. We have reported that α-carbonyl radicals 1, generated from the corresponding iodo ketones or enones, underwent intramolecular radical cyclization smoothly to afford products 2.1, 2,3

  12. Cobalt carbonyl catalyzed olefin hydroformylation in supercritical carbon dioxide (United States)

    Rathke, Jerome W.; Klingler, Robert J.


    A method of olefin hydroformylation is provided wherein an olefin reacts with a carbonyl catalyst and with reaction gases such as hydrogen and carbon monoxide in the presence of a supercritical reaction solvent, such as carbon dioxide. The invention provides higher yields of n-isomer product without the gas-liquid mixing rate limitation seen in conventional Oxo processes using liquid media.

  13. Comparing Carbonyl Chemistry in Comprehensive Introductory Organic Chemistry Textbooks (United States)

    Nelson, Donna J.; Kumar, Ravi; Ramasamy, Saravanan


    Learning the chemistry of compounds containing carbonyl groups is difficult for undergraduate students partly because of a convolution of multiple possible reaction sites, competitive reactions taking place at those sites, different criteria needed to discern between the mechanisms of these reactions, and no straightforward selection method…

  14. Efficient Nd Promoted Rh Catalysts for Vapor Phase Methanol Carbonylation

    Institute of Scientific and Technical Information of China (English)

    Shu Feng ZHANG; Qing Li QIAN; Ping Lai PAN; Yi CHEN; Guo Qing YUAN


    A Nd promoted-Rh catalysts supported on polymer-derived carbon beads for vapor-phase methanol carbonylation was developed. Rh-Nd bimetallic catalysts obviously have higher activity than that of supported Rh catalyst under similar reaction condition. The difference between the activity of above two catalyst systems is clearly caused by the intrinsic properties generated by the introduction of Nd.

  15. Contamination of coal benzol by carbonyl compound impurities

    Energy Technology Data Exchange (ETDEWEB)

    Yakovleva, T.P.


    The origin of most carbonyl compounds in nitration-grade benzene produced from coke-oven crude benzole (causing problems in isopropylbenzene production) was concluded to be the piperylene fraction (a by-product of isoprene manufacture) used as an additive in the washing of the benzene with sulphuric acid.

  16. Metal-Diazo Radicals of α-Carbonyl Diazomethanes (United States)

    Li, Feifei; Xiao, Longqiang; Liu, Lijian


    Metal-diazo radicals of α-carbonyl diazomethanes are new members of the radical family and are precursors to metal-carbene radicals. Herein, using electron paramagnetic resonance spectroscopy with spin-trapping, we detect diazo radicals of α-carbonyl diazomethanes, induced by [RhICl(cod)]2, [CoII(por)] and PdCl2, at room temperature. The unique quintet signal of the Rh-diazo radical was observed in measurements of α-carbonyl diazomethane adducts of [RhICl(cod)]2 in the presence of 5,5-dimethyl-pyrroline-1-N-oxide (DMPO). DFT calculations indicated that 97.2% of spin density is localized on the diazo moiety. Co- and Pd-diazo radicals are EPR silent but were captured by DMPO to form spin adducts of DMPO-N• (triplet-of-sextets signal). The spin-trapping also provides a powerful tool for detection of metal-carbene radicals, as evidenced by the DMPO-trapped carbene radicals (DMPO-C•, sextet signal) and 2-methyl-2-nitrosopropane-carbene adducts (MNP-C•, doublet-of-triplets signal). The transformation of α-carbonyl diazomethanes to metal-carbene radicals was confirmed to be a two-step process via metal-diazo radicals.

  17. Frustrated Lewis pairs-assisted reduction of carbonyl compounds

    DEFF Research Database (Denmark)

    Marek, Ales; Pedersen, Martin Holst Friborg


    An alternative and robust method for the reduction of carbonyl groups by frustrated Lewis pairs (FLPs) is reported in this paper. With its very mild reaction conditions, good to excellent yields, absolute regioselectivity and the non-metallic character of the reagent, it provides an excellent tool...

  18. - Wave Spectrum of Carbonyl Diazide in Pursuit of Diazirinone (United States)

    Amberger, Brent K.; Esselman, Brian J.; Woods, R. Claude; McMahon, Robert J.


    Pyrolysis of carbonyl diazide (CO(N_3)_2) has been shown to give diazirinone (CON_2). While diazirione decomposes over the course of a few hours under terrestrial conditions, there is the possibility for it to exist in space. In the pursuit of obtaining a rotational spectrum for diazirinone, we have started with the rotational spectroscopy of its immediate precursor, carbonyl diazide. Carbonyl diazide is highly explosive, and requires careful synthesis. Spectra in the range of 260-360 GHz were collected at room temperature and at -60°C. Ab initio calculations at the CCSD/cc-pVDZ level predict that the conformation where both azide groups are syn to the carbonyl is preferred. A second conformation, where one azide is syn and one is anti, is calculated to lie about 2 kcal/ mol higher in energy. Pure rotational transitions for the ground state and multiple low-lying excited vibrational states of the syn- syn conformation are readily observed and assigned. X. Zeng, H. Beckers, H. Willner and J. F. Stanton, Angew. Chem. Int. Ed. 50 (2011), 1720-1723 A. M. Nolan, B. K. Amberger, B. J. Esselman, V. S. Thimmakondu, J. F. Stanton, R. C. Woods, and R. J. McMahon, Inorg. Chem. 51 (2012), 9846-9851

  19. Microwave-assisted efficient synthesis of 2-arylbenzo[b]furans and 2-ferrocenylbenzo[b]furans from readily prepared propargylic alcohols and -iodophenols

    Indian Academy of Sciences (India)

    Liansheng Wu; Xiaokang Shi; Xiaoyun Xu; Fen Liang; Guosheng Huang


    A simple, efficient and expeditious method for synthesis of 2-arylbenzo[b]furans and 2-ferrocenylbenzo[b]furans from readily prepared propargylic alcohols, -iodophenols and silica gel with the catalyst of PdCl2(PPh3)2 (2 mol%)/CuI (2mol%) and microwave-promoted Sonogashira coupling/cyclization reaction is developed. The methodology can produce good to excellent yields. In addition, this method can also be completed in one-pot with iodobenzene, 2-methyl-3-butyn-2-ol and 2-iodo-4-methylphenol as reactants.

  20. Direct Nucleophilic Substitution of Free Allylic Alcohols in Water Catalyzed by FeCl3⋅6 H2O: Which is the Real Catalyst?


    Trillo Alarcón, María Paz; Baeza, Alejandro; Nájera Domingo, Carmen


    The allylic substitution reaction, and particularly the direct allylic amination reaction, of free allylic alcohols in water catalyzed by FeCl3⋅6 H2O is described. This novel environmentally-friendly methodology allows the use of a wide variety of nitrogenated nucleophiles such as sulfonamides, carbamates, benzamides, anilines, benzotriazoles, and azides, generally giving good yields of the corresponding substitution products. The synthetic applicability of the process is also demonstrated be...

  1. Plasma protein carbonyl levels and breast cancer risk. (United States)

    Rossner, Pavel; Terry, Mary Beth; Gammon, Marilie D; Agrawal, Meenakshi; Zhang, Fang Fang; Ferris, Jennifer S; Teitelbaum, Susan L; Eng, Sybil M; Gaudet, Mia M; Neugut, Alfred I; Santella, Regina M


    To study the role of oxidative stress in breast cancer risk, we analysed plasma levels of protein carbonyls in 1050 cases and 1107 controls. We found a statistically significant trend in breast cancer risk in relation to increasing quartiles of plasma protein carbonyl levels (OR = 1.2, 95% CI = 0.9-1.5; OR = 1.5, 95% CI = 1.2-2.0; OR = 1.6, 95% CI = 1.2-2.1, for the 2(nd), 3(rd) and 4(th) quartile relative to the lowest quartile, respectively, P for trend = 0.0001). The increase in risk was similar for younger ( or = 15 grams/day for 4(th) quartile versus lowest quartile OR = 2.3, 95% CI = 1.1-4.7), and hormone replacement therapy use (HRT, OR = 2.6, 95% CI = 1.6-4.4 for 4(th) quartile versus lowest quartile). The multiplicative interaction terms were statistically significant only for physical activity and HRT. The positive association between plasma protein carbonyl levels and breast cancer risk was also observed when the analysis was restricted to women who had not received chemotherapy or radiation therapy prior to blood collection. Among controls, oxidized protein levels significantly increased with cigarette smoking and higher fruit and vegetable consumption, and decreased with alcohol consumption >30 grams per day. Women with higher levels of plasma protein carbonyl and urinary 15F(2t)-isoprostane had an 80% increase in breast cancer risk (OR = 1.8, 95% CI = 1.2-2.6) compared to women with levels below the median for both markers of oxidative stress. In summary, our results suggest that increased plasma protein carbonyl levels may be associated with breast cancer risk.

  2. Mystery of 1-Vinylpropargyl Formation from Acetylene Addition to the Propargyl Radical: An Open-and-Shut Case. (United States)

    da Silva, Gabriel


    The addition of acetylene (C2H2) to the propargyl radical (C3H3) initiates a cascade of molecular weight growth reactions that result in the production of polycyclic aromatic hydrocarbons (PAHs) in flames. Although it is well-established that the first reaction step produces the cyclic C5H5 radical cyclopentadienyl (c-C5H5), recent studies have also detected significant quantities of the open-chain form, 1-vinylpropargyl (l-C5H5). This work presents a mechanism for the C3H3 + C2H2 reaction from ab initio calculations, which includes pathways for the formation of both the open and shut isomers as well as for their interconversion. Formation of both isomers proceeds from the initial HCCCH2CHCH(•) reaction adduct with similar barriers, both well below the entrance channel energy. Subsequent isomerization of l-C5H5 with c-C5H5 also transpires at below the energy of the reactants, although this process connects two deep wells (being resonance stabilized radicals), and must compete with collisional energy transfer. An RRKM theory/master equation model is developed for the reported C5H5 reaction mechanism. Master equation simulations suggest that both cyclic and open-chain isomers are expected to form from the C3H3 + C2H2 reaction across a range of temperatures, although the lifetime of l-C5H5 is relatively short for rearrangement to c-C5H5.

  3. Optimized biotin-hydrazide enrichment and mass spectrometry analysis of peptide carbonyls

    DEFF Research Database (Denmark)

    Havelund, Jesper F.; Wojdyla, K; Jensen, O. N.;

    Irreversible cell damage through protein carbonylation is the result of reaction with reactive oxygen species (ROS) and has been coupled to many diseases. The precise molecular consequences of protein carbonylation, however, are still not clear. The localization of the carbonylated amino acid is ...

  4. A specific gas chromatographic detector for carbonyl compounds, based on polarography. (United States)

    Fleet, B; Risby, T H


    The evaluation of a specific gas Chromatographie detector for carbonyl compounds is described. This is based on the polarographic reduction of the Girard T hydrazone derivative which is formed when the carbonyl compound is absorbed in a buffered supporting electrolyte containing the carbonyl reagent. The detector was used to monitor the separation of a homologous series of alkanals.

  5. Low pressure carbonylation of benzyl chloride = Die carbonylierung von benzylchlorid bei niedrigen drücken

    NARCIS (Netherlands)

    Luggenhorst, H.J.; Westerterp, K.R.


    For carbonylations, metal carbonyls, particularly cobalt and iron carbonyls, are often used as catalysts. These reactions take place under rather drastic reaction conditions, e.g. 200–300 °C and 60–100 MPa. In some patents it is stated that similar reactions using the same catalysts can also be carr

  6. Carbonyl compounds in gas and particle phases of mainstream cigarette smoke. (United States)

    Pang, Xiaobing; Lewis, Alastair C


    Carbonyl compounds (carbonyls) are important constituents of cigarette smoke and some are toxic and may be carcinogenic or mutagenic to humans. In this study carbonyl emissions in the gas and particle phases of mainstream cigarette smoke were assessed by GC-MS with pentafluorophenyl hydrazine (PFPH) derivatization. Seven brands of cigarettes and one brand of cigar common in the UK market and having differing nicotine, tar and carbon monoxide yields were investigated. Sixteen carbonyl components were identified in gaseous emissions and twenty in the particle phase. In the gaseous emissions, acetaldehyde presented as the predominant species, followed by formaldehyde, 2-propenal, and pentanal. In the particulate emissions, 1-hydroxy-2-propanone was the most abundant followed by formaldehyde, benzaldehyde, and 2,5-dimethylbenzaldehyde. Significant differences were found in carbonyl emissions among the brands of cigarettes. The gaseous carbonyl emissions varied in the range of 216-405 μg cigarette(-1) (μg cig(-1)) and the particulate carbonyl emissions varied in the range of 23-127 μg cig(-1). Positive correlations were found between the total emission of carbonyls, tar yield and carbon monoxide yield. Similar gas/particle (G/P) partitioning ratios of carbonyls were found among all cigarettes, which implies that G/P partitions of carbonyls in smoke mainly depend on the physical properties of the carbonyls. The gaseous carbonyl emissions were enhanced by 40% to 130% when some of the water, accounting for 8-12% of cigarettes in mass, was removed from the tobacco. Non-filtered cigarettes showed significantly higher carbonyl emissions compared to their filtered equivalents. Carbonyl particulate accounted for 11-19% by mass of total particulate matter from tobacco smoke. The cigar generated 806 μg cig(-1) gaseous and 141 μg cig(-1) particulate carbonyls, which is 2-4 times greater than the cigarettes.

  7. Carbonyl Alkyl Nitrates as Trace Constituents in Urban Air (United States)

    Woidich, S.; Gruenert, A.; Ballschmiter, K.


    Organic nitrates, esters of nitric acid, significantly contribute to the entire pool of odd nitrogen (NOY) in the atmosphere. Organic nitrates are formed in NO rich air by degradation of alkanes and alkenes initiated by OH and NO3 radicals during daytime and nighttime, respectively. Bifunctional organonitrates like the alkyl dinitrates and hydroxy alkyl nitrates are formed primarily from alkenes. The two main sources for Alkenes are traffic emissions and naturally occurring terpenes. So far a broad spectrum of alkyl dinitrates and hydroxy alkyl nitrates including six different isoprene nitrates has been identified in urban and marine air (1-3). We report here for the first time about the group of C4 C7 carbonyl alkyl nitrates as trace constituents in urban air collected on the campus of the University of Ulm Germany, and in the downtown area of Salt Lake City, Utah. Air sampling was done by high volume sampling (flow rate 25 m3/h) using a layer of 100 g silica gel (particle diameter 0.2 - 0.5 mm) as adsorbent. The organic nitrates were eluted from the silica gel by pentane/acetone (4:1, w/w) and the extract was concentrated to a volume of 500 µL for a group separation using normal phase HPLC. Final analysis was performed by high resolution capillary gas chromatography with electron capture detection as well as by mass selective detection in the (CH4)NCI mode using NO2- = m/e 46 as the indicator mass. The carbonyl alkyl nitrates were identified by self synthesized reference standards . So far we have identified eight non-branched a-carbonyl alkyl nitrates (vicinal carbonyl alkyl nitrates), two b-carbonyl alkyl nitrates and one g-carbonyl alkyl nitrate with carbon chains ranging from C4 to C7. The mixing ratios are between 0.05 and 0.30 ppt(v) for daytime samples and are two to three times higher for samples taken at night. (1) M. Schneider, O. Luxenhofer, Angela Deißler, K. Ballschmiter: 2C1-C15 Alkyl Nitrates, Benzyl Nitrate, and Bifunctional Nitrates

  8. Preparation of Well-Defined Propargyl-Terminated Tetra-Arm Poly(N-isopropylacrylamides and Their Click Hydrogels Crosslinked with β-cyclodextrin

    Directory of Open Access Journals (Sweden)

    Jianquan Wang


    Full Text Available As an important class of reversible deactivation radical polymerization (RDRP, reversible addition fragmentation chain transfer (RAFT polymerization has attracted great attention attributed to its facile and flexible features to prepare well-defined polymers with different complex structures. In addition, the combination of RAFT with click chemistry provides more effective strategies to fabricate advanced functional materials. In this work, a series of temperature responsive tetra-arm telechelic poly(N-isopropylacrylamides (PNIPAs with propargyl end groups were prepared for the first time through RAFT and subsequent aminolysis/Michael addition modification. The temperature sensitivities of their aqueous solutions were researched via turbidity measurement. It was found that the phase transition temperature of obtained PNIPAs increased with their molecular weights ascribed to their distinctions in the hydrophobic/hydrophilic balance. Subsequently, β-cyclodextrin (β-CD functionalized with azide moieties was used to crosslink the prepared propargyl-terminated tetra-arm PNIPAs through click chemistry, fabricating corresponding hydrogels with thermoresponse. Similar to their precursors, the hydrogels demonstrated the same dependence of volume phase transition temperature (VPTT on their molecular weights. In addition, the incorporation of β-CD and the residual groups besides crosslinking may provide a platform for imparting additional functions such as inclusion and adsorption as well as further functionalization.

  9. Chemical Kinetics of Hydrogen Atom Abstraction from Allylic Sites by (3)O2; Implications for Combustion Modeling and Simulation. (United States)

    Zhou, Chong-Wen; Simmie, John M; Somers, Kieran P; Goldsmith, C Franklin; Curran, Henry J


    Hydrogen atom abstraction from allylic C-H bonds by molecular oxygen plays a very important role in determining the reactivity of fuel molecules having allylic hydrogen atoms. Rate constants for hydrogen atom abstraction by molecular oxygen from molecules with allylic sites have been calculated. A series of molecules with primary, secondary, tertiary, and super secondary allylic hydrogen atoms of alkene, furan, and alkylbenzene families are taken into consideration. Those molecules include propene, 2-butene, isobutene, 2-methylfuran, and toluene containing the primary allylic hydrogen atom; 1-butene, 1-pentene, 2-ethylfuran, ethylbenzene, and n-propylbenzene containing the secondary allylic hydrogen atom; 3-methyl-1-butene, 2-isopropylfuran, and isopropylbenzene containing tertiary allylic hydrogen atom; and 1-4-pentadiene containing super allylic secondary hydrogen atoms. The M06-2X/6-311++G(d,p) level of theory was used to optimize the geometries of all of the reactants, transition states, products and also the hinder rotation treatments for lower frequency modes. The G4 level of theory was used to calculate the electronic single point energies for those species to determine the 0 K barriers to reaction. Conventional transition state theory with Eckart tunnelling corrections was used to calculate the rate constants. The comparison between our calculated rate constants with the available experimental results from the literature shows good agreement for the reactions of propene and isobutene with molecular oxygen. The rate constant for toluene with O2 is about an order magnitude slower than that experimentally derived from a comprehensive model proposed by Oehlschlaeger and coauthors. The results clearly indicate the need for a more detailed investigation of the combustion kinetics of toluene oxidation and its key pyrolysis and oxidation intermediates. Despite this, our computed barriers and rate constants retain an important internal consistency. Rate constants

  10. Phenolic carbonyls undergo rapid aqueous photodegradation to form low-volatility, light-absorbing products (United States)

    Smith, Jeremy D.; Kinney, Haley; Anastasio, Cort


    We investigated the aqueous photochemistry of six phenolic carbonyls - vanillin, acetovanillone, guaiacyl acetone, syringaldehyde, acetosyringone, and coniferyl aldehyde - that are emitted from wood combustion. The phenolic carbonyls absorb significant amounts of solar radiation and decay rapidly via direct photodegradation, with lifetimes (τ) of 13-140 min under Davis, CA winter solstice sunlight at midday (solar zenith angle = 62°). The one exception is guaiacyl acetone, where the carbonyl group is not directly connected to the aromatic ring: This species absorbs very little sunlight and undergoes direct photodegradation very slowly (τ > 103 min). We also found that the triplet excited states (3C*) of the phenolic carbonyls rapidly oxidize syringol (a methoxyphenol without a carbonyl group), on timescales of 1-5 h for solutions containing 5 μM phenolic carbonyl. The direct photodegradation of the phenolic carbonyls, and the oxidation of syringol by 3C*, both efficiently produce low volatility products, with SOA mass yields ranging from 80 to 140%. Contrary to most aliphatic carbonyls, under typical fog conditions we find that the primary sink for the aromatic phenolic carbonyls is direct photodegradation in the aqueous phase. In areas of significant wood combustion, phenolic carbonyls appear to be small but significant sources of aqueous SOA: over the course of a few hours, nearly all of the phenolic carbonyls will be converted to SOA via direct photodegradation, enhancing the POA mass from wood combustion by approximately 3-5%.

  11. Genome wide association mapping in Arabidopsis thaliana identifies novel genes involved in linking allyl glucosinolate to altered biomass and defense

    Directory of Open Access Journals (Sweden)

    Marta Francisco


    Full Text Available A key limitation in modern biology is the ability to rapidly identify genes underlying newly identified complex phenotypes. Genome wide association studies (GWAS have become an increasingly important approach for dissecting natural variation by associating phenotypes with genotypes at a genome wide level. Recent work is showing that the Arabidopsis thaliana defense metabolite, allyl glucosinolate (GSL, may provide direct feedback regulation, linking defense metabolism outputs to the growth and defense responses of the plant. However, there is still a need to identify genes that underlie this process. To start developing a deeper understanding of the mechanism(s that modulate the ability of exogenous allyl GSL to alter growth and defense, we measured changes in plant biomass and defense metabolites in a collection of natural 96 A. thaliana accessions fed with 50 µM of allyl GSL. Exogenous allyl GSL was introduced exclusively to the roots and the compound transported to the leaf leading to a wide range of heritable effects upon plant biomass and endogenous GSL accumulation. Using natural variation we conducted GWAS to identify a number of new genes which potentially control allyl responses in various plant processes. This is one of the first instances in which this approach has been successfully utilized to begin dissecting a novel phenotype to the underlying molecular/polygenic basis.

  12. Palladacyclic imidazoline-naphthalene complexes: synthesis and catalytic performance in Pd(II)-catalyzed enantioselective reactions of allylic trichloroacetimidates. (United States)

    Cannon, Jeffrey S; Frederich, James H; Overman, Larry E


    A new family of air- and moisture-stable enantiopure C,N-palladacycles (PIN-acac complexes) were prepared in good overall yield in three steps from 2-iodo-1-naphthoic acid and enantiopure β-amino alcohols. Three of these PIN complexes were characterized by single-crystal X-ray analysis. As anticipated, the naphthalene and imidazoline rings of PIN-acac complexes 18a and 18b were canted significantly from planarity and projected the imidazoline substituents R(1) and R(2) on opposite faces of the palladium square plane. Fifteen PIN complexes were evaluated as catalysts for the rearrangement of prochiral (E)-allylic trichloroacetimidate 19 (eq 2) and the S(N)2' allylic substitution of acetic acid with prochiral (Z)-allylic trichloroacetimidate 23. Although these complexes were kinetically poor catalysts for the Overman rearrangement, they were good catalysts for the allylic substitution reaction, providing branched allylic esters in high yield. However, enantioselectivities were low to moderate and significantly less than that realized with palladacyclic complexes of the COP family. Computational studies support an anti-acetoxypalladation/syn-deoxypalladation mechanism analogous to that observed with COP catalysts. The computational study further suggests that optimizing steric influence in the vicinity of the carbon ligand of a chiral C,N-palladacycle, rather than near the nitrogen heterocycle, is the direction to pursue in future development of improved enantioselective catalysts of this motif.

  13. Metal Carbonyl-Hydrosilane Reactions and Hydrosilation Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Cutler, A. R.


    Manganese carbonyl complexes serve as hydrosilation precatalysts for selectively transforming a carbonyl group into a siloxy methylene or a fully reduced methylene group. Substrates of interest include (1) aldehydes, ketones, carboxylic acids, silyl esters, and esters, and (2) their organometallic acyl counterparts. Three relevant catalytic reactions are shown. Two types of manganese precatalysts have been reported: (a) alkyl and acyl complexes (L)(C0){sub 4}MnR [L = CO, PPh{sub 3}; R = COCH{sub 3}, COPh, CH{sub 3}] and (b) halides (CO){sub 5}MnX and [(CO){sub 4}MnX]{sub 2} (X = Br, I). The former promote hydrosilation and deoxygenation catalysis; the latter promote dehydrogenative silation of alcohols and carboxylic acids as well as hydrosilation and deoxygenation of some metallocarboxylic acid derivatives. In every case studied, these Mn precatalysts are far more reactive or selective than traditional Rh(I) precatalysts.

  14. Nuclear chemistry. Synthesis and detection of a seaborgium carbonyl complex. (United States)

    Even, J; Yakushev, A; Düllmann, Ch E; Haba, H; Asai, M; Sato, T K; Brand, H; Di Nitto, A; Eichler, R; Fan, F L; Hartmann, W; Huang, M; Jäger, E; Kaji, D; Kanaya, J; Kaneya, Y; Khuyagbaatar, J; Kindler, B; Kratz, J V; Krier, J; Kudou, Y; Kurz, N; Lommel, B; Miyashita, S; Morimoto, K; Morita, K; Murakami, M; Nagame, Y; Nitsche, H; Ooe, K; Qin, Z; Schädel, M; Steiner, J; Sumita, T; Takeyama, M; Tanaka, K; Toyoshima, A; Tsukada, K; Türler, A; Usoltsev, I; Wakabayashi, Y; Wang, Y; Wiehl, N; Yamaki, S


    Experimental investigations of transactinoide elements provide benchmark results for chemical theory and probe the predictive power of trends in the periodic table. So far, in gas-phase chemical reactions, simple inorganic compounds with the transactinoide in its highest oxidation state have been synthesized. Single-atom production rates, short half-lives, and harsh experimental conditions limited the number of experimentally accessible compounds. We applied a gas-phase carbonylation technique previously tested on short-lived molybdenum (Mo) and tungsten (W) isotopes to the preparation of a carbonyl complex of seaborgium, the 106th element. The volatile seaborgium complex showed the same volatility and reactivity with a silicon dioxide surface as those of the hexacarbonyl complexes of the lighter homologs Mo and W. Comparison of the product's adsorption enthalpy with theoretical predictions and data for the lighter congeners supported a Sg(CO)6 formulation.

  15. Emissions of Toxic Carbonyls in an Electronic Cigarette

    Directory of Open Access Journals (Sweden)

    Guthery William


    Full Text Available Electronic cigarettes (e-cigs provide a smoke-free alternative for inhalation of nicotine without the vast array of toxic and carcinogenic combustion products produced by tobacco smoke. Elevated levels of toxic carbonyls may be generated during vaporisation; however, it is unclear whether that is indicative of a fault with the device or is due to the applied conditions of the test. A device, designed and built at this facility, was tested to determine the levels of selected toxic carbonyls. The reservoir was filled with approximately 960 mg of an e-liquid formulation containing 1.8% (w/v nicotine. Devices were puffed 200 times in blocks of 40 using a standardised regime consisting of a 55 mL puff volume; 3 s puff duration; 30 s puff interval; square wave puff profile. Confirmatory testing for nicotine and total aerosol delivery resulted in mean (n = 8 values of 10 mg (RSD 12.3% and 716 mg (RSD 11.2%, respectively. Emissions of toxic carbonyls were highly variable yet were between < 0.1% and 22.9% of expected levels from a Kentucky Reference Cigarette (K3R4F puffed 200 times under Health Canada Intense smoking conditions. It has been shown that a device built to a high specification with relatively consistent nicotine and aerosol delivery emits inconsistent levels of carbonyls. The exposure is greatly reduced when compared with lit tobacco products. However, it was observed that as the reservoirs neared depletion then emission levels were significantly higher

  16. Antagonismo das associações de clodinafop-propargyl com metsulfuron-methyl e 2,4-D no controle de azevém (Lolium multiflorum Antagonistic action of clodinafop-propargyl associated with Metsulfuron-methyl and 2,4-D in the control of italian ryegrass (Lolium multiflorum

    Directory of Open Access Journals (Sweden)

    M.M. Trezzi


    Full Text Available Em geral, a eficiência de herbicidas inibidores da ACCase é reduzida quando da aplicação em conjunto com herbicidas latifolicidas. Dois experimentos - em casa de vegetação e campo - objetivaram determinar a existência de antagonismo nas associações de clodinafop-propargyl a metsulfuron-methyl ou 2,4-D, para controle de azevém anual. Em casa de vegetação, o delineamento foi o completamente casualizado, com 21 tratamentos compostos pela aplicação de clodinafop (0, 3, 6, 12, 24, 48 e 96 g ha-1 isolado ou em mistura com metsulfuron-methyl (2 e 4 g ha-1 ou 2,4-D (470 g ha-1. Em campo, o delineamento foi de blocos casualizados, com 12 tratamentos, arranjados em fatorial 6 x 2, composto pelos níveis de clodinafop-propargyl (0, 3, 6, 12, 24, 48 e 96 g ha¹ isolado ou em mistura com metsulfuron-methyl (2 g ha-1. A avaliação visual de controle, em casa de vegetação, revelou I50 das misturas de clodinafop-propargyl + metsulfuron-methyl (2 e 4 g ha-1 ou clodinafop-propargyl + 2,4-D (470 g ha-1, respectivamente, 33, 84 e 151% superiores ao de clodinafop-propargyl isolado. Já para matéria verde de azevém, o I50 das misturas supracitadas foi, respectivamente, 119, 244 e 72% superior ao de clodinafop-propargyl isolado. Em campo, ocorreu redução da matéria verde de azevém com a elevação dos níveis de clodinafop-propargyl isolado, mas não houve variação da matéria verde com a elevação dos níveis de clodinafop-propargyl, em associação a metsulfuron-methyl. Os resultados evidenciam a existência de antagonismo entre clodinafop-propargyl e os herbicidas metsulfuron-methyl e 2,4-D. São feitas considerações sobre as possíveis vantagens da aplicação dos herbicidas em mais de uma operação de controle, em comparação à associação entre graminicidas e latifolicidas.The efficacy of ACCase inhibitors is usually reduced when tank-mixed with broad leaf herbicides. A greenhouse and a field experiments were carried out to

  17. Resonance energies of the allyl cation and allyl anion: contribution by resonance and inductive effects toward the acidity and hydride abstraction enthalpy of propene. (United States)

    Barbour, Josiah B; Karty, Joel M


    Density functional theory was employed to calculate the acidities and hydride abstraction enthalpies of propene (3) and propane (4), along with their vinylogues (5 and 6, respectively). The same reaction enthalpies were calculated for the propene vinylogues in which the terminal vinyl group was rotated perpendicular to the rest of the conjugated system (7). The contribution by resonance and inductive effects toward the acidity and hydride abstraction enthalpy of each vinylogue of 5 (n = 1-3) was computed and extrapolated to n = 0 (the parent propene system). The resonance energies of the allyl cation and anion were determined to be about 20-22 and 17-18 kcal/mol, respectively. Comparisons are made to resonance energies calculated using other methodologies.

  18. Iron(III)-catalysed carbonyl-olefin metathesis. (United States)

    Ludwig, Jacob R; Zimmerman, Paul M; Gianino, Joseph B; Schindler, Corinna S


    The olefin metathesis reaction of two unsaturated substrates is one of the most powerful carbon-carbon-bond-forming reactions in organic chemistry. Specifically, the catalytic olefin metathesis reaction has led to profound developments in the synthesis of molecules relevant to the petroleum, materials, agricultural and pharmaceutical industries. These reactions are characterized by their use of discrete metal alkylidene catalysts that operate via a well-established mechanism. While the corresponding carbonyl-olefin metathesis reaction can also be used to construct carbon-carbon bonds, currently available methods are scarce and severely hampered by either harsh reaction conditions or the required use of stoichiometric transition metals as reagents. To date, no general protocol for catalytic carbonyl-olefin metathesis has been reported. Here we demonstrate a catalytic carbonyl-olefin ring-closing metathesis reaction that uses iron, an Earth-abundant and environmentally benign transition metal, as a catalyst. This transformation accommodates a variety of substrates and is distinguished by its operational simplicity, mild reaction conditions, high functional-group tolerance, and amenability to gram-scale synthesis. We anticipate that these characteristics, coupled with the efficiency of this reaction, will allow for further advances in areas that have historically been enhanced by olefin metathesis.

  19. Carbonylation of Ethene Catalysed by Pd(II-Phosphine Complexes

    Directory of Open Access Journals (Sweden)

    Gianni Cavinato


    Full Text Available This review deals with olefin carbonylation catalysed by Pd(II-phosphine complexes in protic solvents. In particular, the results obtained in the carbonylation with ethene are reviewed. After a short description of the basic concepts relevant to this catalysis, the review treats in greater details the influence of the bite angle, skeletal rigidity, electronic and steric bulk properties of the ligand on the formation of the products, which range from high molecular weight perfectly alternating polyketones to methyl propanoate. It is shown that the steric bulk plays a major role in directing the selectivity. Particular emphasis is given to the factors governing the very active and selective catalysis to methyl propanoate, including the mechanism of the catalytic cycles with diphosphine- and monophosphine-catalysts. A brief note on the synthesis of methyl propanoate using a “Lucite” type catalyst in ionic liquids is also illustrated. A chapter is dedicated to the carbonylation of olefins in aqueous reaction media. The nonalternating CO-ethene copolymerization is also treated.

  20. Iron(III)-catalysed carbonyl-olefin metathesis (United States)

    Ludwig, Jacob R.; Zimmerman, Paul M.; Gianino, Joseph B.; Schindler, Corinna S.


    The olefin metathesis reaction of two unsaturated substrates is one of the most powerful carbon-carbon-bond-forming reactions in organic chemistry. Specifically, the catalytic olefin metathesis reaction has led to profound developments in the synthesis of molecules relevant to the petroleum, materials, agricultural and pharmaceutical industries. These reactions are characterized by their use of discrete metal alkylidene catalysts that operate via a well-established mechanism. While the corresponding carbonyl-olefin metathesis reaction can also be used to construct carbon-carbon bonds, currently available methods are scarce and severely hampered by either harsh reaction conditions or the required use of stoichiometric transition metals as reagents. To date, no general protocol for catalytic carbonyl-olefin metathesis has been reported. Here we demonstrate a catalytic carbonyl-olefin ring-closing metathesis reaction that uses iron, an Earth-abundant and environmentally benign transition metal, as a catalyst. This transformation accommodates a variety of substrates and is distinguished by its operational simplicity, mild reaction conditions, high functional-group tolerance, and amenability to gram-scale synthesis. We anticipate that these characteristics, coupled with the efficiency of this reaction, will allow for further advances in areas that have historically been enhanced by olefin metathesis.

  1. Metabolic fate of the (14)C-labeled herbicide clodinafop-propargyl in a sediment-water system. (United States)

    Yuan, Ye; Weitzel, Pascal; Schäffer, Andreas; Schmidt, Burkhard


    The metabolic fate of (14)C-phenyl-labeled herbicide clodinafop-propargyl ((14)C-CfP) was studied for 28 days in lab assays using a sediment-water system derived from a German location. Mineralization was 5.21% of applied (14)C after 28 days exhibiting a distinct lag phase until day 14 of incubation. Portions of radioactivity remaining in water phases decreased at moderate rate to 18.48% after 28 days; 62.46% were still detected in water after 14 days. Soxhlet extraction of the sediment using acetonitrile released 35.56% of applied (14)C with day 28, while 33.99% remained as non-extractable residues. A remarkable increase of bound (14)C was observed between 14 and 28 days correlating with the distinct increase of mineralization. No correlation was found throughout incubation with microbial activity of the sediment as determined by dimethyl sulfoxide reduction. Dissolved oxygen and pH value of water phases remained almost constant for 28 days. Analyses of Soxhlet extracts of the sediment and ethyl acetate extracts of water phases by radio-TLC and radio-HPLC revealed that CfP was rapidly cleaved to free acid clodinafop (Cf), which was further (bio-) transformed. DT50 values (based on radio-HPLC) were below 1 day (CfP) and slightly above 28 days (Cf). Further metabolites were not detected. Fractionation of humic and non-humic components of the sediment demonstrated that CfP's non-extractable residues were predominantly associated with fulvic acids up to 14 days of incubation (3.36%), whereas after 28 days, the majority of radioactivity was found in the humin/mineral fraction (13.30% of applied (14)C). Due to high-performance size-exclusion chromatography of the fulvic acids fraction derived from assays incubated for 28 days, this portion of (14)C was firmly, possibly covalently bound to fulvic acids and did not consist of CfP or Cf. Using an isolation strategy comprising preincubation of sediment with CfP and mineralization of (14)C-CfP as criterion, a microorganism

  2. Communication: A vibrational study of propargyl cation using the vacuum ultraviolet laser velocity-map imaging photoelectron method

    Energy Technology Data Exchange (ETDEWEB)

    Gao Hong; Lu Zhou; Yang Lei; Zhou Jingang; Ng, C. Y. [Department of Chemistry, University of California, Davis, California 95616 (United States)


    By employing the vacuum ultraviolet (VUV) laser velocity-map imaging photoelectron (VUV-VMI-PE) method, we have obtained a vibrationally resolved photoelectron spectrum of gaseous propargyl radical [C{sub 3}H{sub 3}(X{sup 2}B{sub 1})] in the energy range of 0-4600 cm{sup -1} above its ionization energy. The cold C{sub 3}H{sub 3} radicals were produced from a supersonically cooled radical beam source based on 193 nm ArF photodissociation of C{sub 3}H{sub 3}Cl. The VUV-VMI-PE spectrum of C{sub 3}H{sub 3} thus obtained reveals a Franck-Condon factor (FCF) pattern with a highly dominant origin band along with weak vibrational progressions associated with excitations of the C-C {nu}{sub 5}{sup +}(a{sub 1}) and C{identical_to}C {nu}{sub 3}{sup +}(a{sub 1}) symmetric stretching modes and the CCH {nu}{sub 7}{sup +}(b{sub 1}) out-of-plane bending mode of C{sub 3}H{sub 3}{sup +}(X{sup 1}A{sub 1}). The {nu}{sub 5}{sup +}(a{sub 1}) vibrational frequency of 1120 cm{sup -1} determined in the present study is lower than the value deduced from the recent Ar-tagged infrared photodissociation study by 102 cm{sup -1}, confirming the highly accurate vibrational frequency predictions obtained by the most recent state-of-the-art ab initio quantum calculations. The observation of the FCF disallowed {nu}{sub 7}{sup +}(b{sub 1}) mode is indicative of vibronic interactions. The discrepancy observed between the FCF pattern determined in the present study and that predicted by a recent high-level quantum theoretical investigation can be taken as evidence that the potential energy surfaces used in the latter theoretical study are in need of improvement in order to provide a reliable FCF prediction for the C{sub 3}H{sub 3}/C{sub 3}H{sub 3}{sup +} photoionization system.

  3. S-Allyl cysteine improves nonalcoholic fatty liver disease in type 2 diabetes Otsuka Long-Evans Tokushima Fatty rats via regulation of hepatic lipogenesis and glucose metabolism. (United States)

    Takemura, Shigekazu; Minamiyama, Yukiko; Kodai, Shintaro; Shinkawa, Hiroji; Tsukioka, Takuma; Okada, Shigeru; Azuma, Hideki; Kubo, Shoji


    It is important to prevent and improve diabetes mellitus and its complications in a safe and low-cost manner. S-Allyl cysteine, an aged garlic extract with antioxidant activity, was investigated to determine whether S-allyl cysteine can improve type 2 diabetes in Otsuka Long-Evans Tokushima Fatty rats with nonalcoholic fatty liver disease. Male Otsuka Long-Evans Tokushima Fatty rats and age-matched Long-Evans Tokushima Otsuka rats were used and were divided into two groups at 29 weeks of age. S-Allyl cysteine (0.45% diet) was administered to rats for 13 weeks. Rats were killed at 43 weeks of age, and detailed analyses were performed. S-Allyl cysteine improved hemoglobinA1c, blood glucose, triglyceride, and low-density lipoprotein cholesterol levels. Furthermore, S-allyl cysteine normalized plasma insulin levels. S-Allyl cysteine activated the mRNA and protein expression of both peroxisome proliferator-activated receptor α and γ, as well as inhibiting pyruvate dehydrogenase kinase 4 in Otsuka Long-Evans Tokushima Fatty rat liver. Sterol regulatory element-binding protein 1c and forkhead box O1 proteins were normalized by S-allyl cysteine in Otsuka Long-Evans Tokushima Fatty rat liver. In conclusions, these findings support the hypothesis that S-allyl cysteine has diabetic and nonalcoholic fatty liver disease therapeutic potential as a potent regulating agent against lipogenesis and glucose metabolism.

  4. Beads,Necklaces, Chains and Strings in Capping Carbonyl Clusters

    Directory of Open Access Journals (Sweden)

    Enos Masheija Kiremire


    Full Text Available The paper attempts to explain at length the close relationship between transition metal carbonyl clusters with main group clusters especially the boranes using the 14n and 4n rules. When the ‘shielding’ electrons are removed from a transition metal carbonyl cluster and becomes ‘naked’, it resembles a corresponding one in the main group elements. A an expanded table of osmium carbonyl clusters was constructed using the capping fragment Os(CO2(14n-2 and the fragment Os(CO3 (14n+0. The table reveals the fact that the known series such closo, nido and arachno are part and parcel of a wide range of series especially the capping series 14n+q, where q takes up negative multiple integers of two including 0 such as such = 0, -2,-4, -6, and so on. The linkage between capping series in transition metal carbonyl clusters has also been identified. Apart from the capping series generated in the table, there is another type of series where the skeletal cluster elements remained the same but the number of carbonyl ligands successively decreased. These types of series are referred to as stripping series. Mapping generating functions were also derived which produces any cluster formula or series required. Also the table shows that many clusters form utilizing some of its atoms as closo nucleus around which the larger ones are built and thus forming clusters within larger clusters. The table may be used to categorize a given cluster formula that falls within its range. Otherwise, using the 14n rule or 4n rule can be used for cluster classification. Furthermore, the table indicated that atoms, fragments and molecules can be classified into series. Through this approach of using series, Hoffmann’s important isolobal relationship of chemical species can splendidly be explained.Using the 14n rule and 4n rules creates a framework under which chemical species such as atoms, fragments, molecules and ions some of which may appear unrelated from main group

  5. Chirality Transfer in Gold(I)-Catalysed Direct Allylic Etherifications of Unactivated Alcohols: Experimental and Computational Study. (United States)

    Barker, Graeme; Johnson, David G; Young, Paul C; Macgregor, Stuart A; Lee, Ai-Lan


    Gold(I)-catalysed direct allylic etherifications have been successfully carried out with chirality transfer to yield enantioenriched, γ-substituted secondary allylic ethers. Our investigations include a full substrate-scope screen to ascertain substituent effects on the regioselectivity, stereoselectivity and efficiency of chirality transfer, as well as control experiments to elucidate the mechanistic subtleties of the chirality-transfer process. Crucially, addition of molecular sieves was found to be necessary to ensure efficient and general chirality transfer. Computational studies suggest that the efficiency of chirality transfer is linked to the aggregation of the alcohol nucleophile around the reactive π-bound Au-allylic ether complex. With a single alcohol nucleophile, a high degree of chirality transfer is predicted. However, if three alcohols are present, alternative proton transfer chain mechanisms that erode the efficiency of chirality transfer become competitive.

  6. Study on the Preparation of Allyl-modified Starch in Isopropyl/Water Medium for Warp Sizing

    Institute of Scientific and Technical Information of China (English)

    LI Man-li; ZHU Zhi-feng; ZHANG Long-qiu


    A new method for the pretreatment of starch by etherification was developed to eliminate the problems of lower grafting efficiency associated with the preparation of starch graft copolymers as warp sizing agents.The etherification of starch with allyl chloride was investigated in order to effectively enhance the reaction efficiency.The technological variables of the reaction considered for evaluating the etherification included sodium hydroxide amount,water content in water-isopropyi alcohol medium,allyl cldoride concentration,reaction temperature and reaction time.The experimental result demonstrated that the variables considered showed evident effect on the reaction efficiency.For the etherification,a condition of 20% for the water content,1.5:1 for the molar ratio of sodium hydroxide to allyl chloride.and at 30℃ under 24h reaction is Sufficient to retain the reaction efficiency above 50%.Furthermore,a contrast test demonstrated that the graft efficiency can be increased with the etherification pretreatment.

  7. Carbonyl compounds in gas and particle phases of mainstream cigarette smoke

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Xiaobing, E-mail: [Department of Chemistry, University of York, Heslington, York, YO10 5DD (United Kingdom); Lewis, Alastair C., E-mail: [National Centre for Atmospheric Science, University of York, Heslington, York, YO10 5DD (United Kingdom)


    Carbonyl compounds (carbonyls) are important constituents of cigarette smoke and some are toxic and may be carcinogenic or mutagenic to humans. In this study carbonyl emissions in the gas and particle phases of mainstream cigarette smoke were assessed by GC-MS with pentafluorophenyl hydrazine (PFPH) derivatization. Seven brands of cigarettes and one brand of cigar common in the UK market and having differing nicotine, tar and carbon monoxide yields were investigated. Sixteen carbonyl components were identified in gaseous emissions and twenty in the particle phase. In the gaseous emissions, acetaldehyde presented as the predominant species, followed by formaldehyde, 2-propenal, and pentanal. In the particulate emissions, 1-hydroxy-2-propanone was the most abundant followed by formaldehyde, benzaldehyde, and 2,5-dimethylbenzaldehyde. Significant differences were found in carbonyl emissions among the brands of cigarettes. The gaseous carbonyl emissions varied in the range of 216-405 {mu}g cigarette{sup -1} ({mu}g cig{sup -1}) and the particulate carbonyl emissions varied in the range of 23-127 {mu}g cig{sup -1}. Positive correlations were found between the total emission of carbonyls, tar yield and carbon monoxide yield. Similar gas/particle (G/P) partitioning ratios of carbonyls were found among all cigarettes, which implies that G/P partitions of carbonyls in smoke mainly depend on the physical properties of the carbonyls. The gaseous carbonyl emissions were enhanced by 40% to 130% when some of the water, accounting for 8-12% of cigarettes in mass, was removed from the tobacco. Non-filtered cigarettes showed significantly higher carbonyl emissions compared to their filtered equivalents. Carbonyl particulate accounted for 11-19% by mass of total particulate matter from tobacco smoke. The cigar generated 806 {mu}g cig{sup -1} gaseous and 141 {mu}g cig{sup -1} particulate carbonyls, which is 2-4 times greater than the cigarettes. - Highlights: {yields} Carbonyl

  8. Non-thermal plasma destruction of allyl alcohol in waste gas: kinetics and modelling (United States)

    DeVisscher, A.; Dewulf, J.; Van Durme, J.; Leys, C.; Morent, R.; Van Langenhove, H.


    Non-thermal plasma treatment is a promising technique for the destruction of volatile organic compounds in waste gas. A relatively unexplored technique is the atmospheric negative dc multi-pin-to-plate glow discharge. This paper reports experimental results of allyl alcohol degradation and ozone production in this type of plasma. A new model was developed to describe these processes quantitatively. The model contains a detailed chemical degradation scheme, and describes the physics of the plasma by assuming that the fraction of electrons that takes part in chemical reactions is an exponential function of the reduced field. The model captured the experimental kinetic data to less than 2 ppm standard deviation.

  9. Direct asymmetric allylic alkenylation of N-itaconimides with Morita-Baylis-Hillman carbonates

    KAUST Repository

    Yang, Wenguo


    The asymmetric allylic alkenylation of Morita-Baylis-Hillman (MBH) carbonates with N-itaconimides as nucleophiles has been developed using a commercially available Cinchona alkaloid catalyst. A variety of multifunctional chiral α-methylene-β-maleimide esters were attained in moderate to excellent yields (up to 99%) and good to excellent enantioselectivities (up to 91% ee). The origin of the regio- and stereoselectivity was verified by DFT methods. Calculated geometries and relative energies of various transition states strongly support the observed regio- and enantioselectivity. © 2012 American Chemical Society.

  10. Lanthanum triflate triggered synthesis of tetrahydroquinazolinone derivatives of N-allyl quinolone and their biological assessment

    Directory of Open Access Journals (Sweden)

    Jardosh Hardik H.


    Full Text Available A series of 24 derivatives of tetrahydroquinazolinone has been synthesized by one-pot cyclocondensation reaction of N-allyl quinolones, cyclic β-diketones and (thiourea/N-phenylthiourea in presence of lanthanum triflate catalyst. This methodology allowed us to achieve the products in excellent yield by stirring at room temperature. All the synthesized compounds were investigated against a representative panel of pathogenic strains using broth microdilution MIC (minimum inhibitory concentration method for their in vitro antimicrobial activity. Amongst these sets of heterocyclic compounds 5h, 6b, 6h, 5f, 5l, 5n and 6g found to have admirable activity.

  11. N-(2-Allyl-4-ethoxy-2H-indazol-5-yl-4-methylbenzenesulfonamide

    Directory of Open Access Journals (Sweden)

    Hakima Chicha


    Full Text Available The indazole ring system of the title compound, C19H21N3O3S, is almost planar (r.m.s. deviation = 0.0192 Å and forms dihedral angles of 77.99 (15 and 83.9 (3° with the benzene ring and allyl group, respectively. In the crystal, centrosymmetrically related molecules are connected by pairs of N—H...O hydrogen bonds into dimers, which are further linked by C—H...O hydrogen bonds, forming columns parallel to the b axis.

  12. Thermophysical properties and reaction kinetics of γ-irradiated poly allyl diglycol carbonates nuclear track detector (United States)

    Elmaghraby, Elsayed K.; Seddik, Usama


    Kinetic thermogravimetric technique was used to study the effect of gamma irradiation on the poly allyl diglycol carbonates (PADC) within the dose range from 50 to ? Gy. The approach of Coats-Redfern was used to analyze the data. Results showed that low doses around 50 Gy make the polymer slightly more resistive to heat treatment. Higher radiation doses cause severe effects in the samples accompanied by the formation of lower molecular mass species and consequent crosslinking. Results support the domination of re-polymerization and crosslinking for the γ radiation interaction PADC at dose below about ? Gy, while the situation is inverted above ? Gy in which chain secession dominates.

  13. Synthesis of Aminophosphine Ligands with Binaphthyl Backbones for Silver(I)-catalyzed Enantioselective Allylation of Benzaldehyde

    Institute of Scientific and Technical Information of China (English)

    WANG,Yi(王以); JI,Bao-Ming(吉保明); DING,Kui-Ling(丁奎岭)


    A series of aminophosphine ligands was synthesized from 2amino-2′-hydroxy-1,1′-binaphthyl (NOBIN). Their asymmetric induction efficiency was examined for silver(I)catalyzed enantioselective allylation reaction of benzaldehyde with allyltributyltin.Under the optimized reaction conditions,quantitative yield as well as moderate ee value (54.5% ee)of product was achieved by the catalysis with silver(I)/3 complex. The effects of the binaphthyl backbone and the substituted situated at chelating N, Patoms on enantioselectivity of the reaction were also discussed.

  14. Synthesis of Aryl Allyl Ether in the Recyclable Ionic Liquid [bmim]PF6

    Institute of Scientific and Technical Information of China (English)

    Zhou Mei-Yun; Li Yi-Qun; Xu Xin-Ming


    Ionic liquids, especially imidazonium salts, have recently gained recognition as possible environmentally benign alternative chemical process solvents. This is mainly due to their nonvolatile nature, insolubility in some solvents as well as their ability to dissolve a wide range of organic and inorganic materials, allowing the ionic liquids easy recovery and recycling. Examples of their application in organic reactions have been summarized in a number of recent review articles.1Aryl allyl ether is very useful intermediate in organic synthesis. The Williamson reaction is a well knows method for the preparation ethers. However, the reaction of alkylating agents with the phenoxide ions was conventionally carried out in the organic solvents. The usual solvents for this type of reaction are DCM, 2 DMSO, 3 DMF, 4 CH3CN5 etc. With the current desire to avoid the use of organic molecular solvents in organic synthesis, we decide to investigate the use of the ionic liquid for the alternative solvent for the Williamson reaction to prepare the aryl allyl ethers. The ionic liquid employed here was the moisture stable 1-butyl-3-methylimidazolium hexafluorophosphate [bmim]PF6.6 The ionic liquid is non-volatile, thermally stable, and depending on the anion, can present low immiscible with water,alkanes and dialky ethers. We have now found that aryl allyl ethers can have been obtained from various phenols and allyl bromide in the presence of potassium hydroxide in [bmim]PF6 as a replacement for classical organic solvents in the ambient temperature. The results are shown in Scheme 1.The reaction were carried out by simple mixing the phenolwith the ally bromide and potassium hydroxide in [bmim]PF6 and stirred at room temperature for 4h. The results are summarized in Table 1.In conclusion, Williamson reaction can be successfully conducted in ionic liquid [bmim]PF6 with a number of advantages: the procedure is simple, the reaction condition is mild and the yields are excellent

  15. N-(1-Allyl-3-chloro-4-ethoxy-1H-indazol-5-yl-4-methylbenzenesulfonamide

    Directory of Open Access Journals (Sweden)

    Hakima Chicha


    Full Text Available In the title compound, C19H20ClN3O3S, the benzene ring is inclined to the indazole ring system by 51.23 (8°. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers which stack in columns parallel to [011]. The atoms in the allyl group are disordered over two sets of sites with an occupancy ratio of 0.624 (8:0.376 (8.

  16. [3,3]-sigmatropic rearrangements of fluorinated allyl (Thio)cyanates - a tool for the synthesis of fluorinated (Thio)ureas. (United States)

    Ramb, Daniel C; Kost, Lisa; Haufe, Günter


    The first (thio)cyanate to iso(thio)cyanate rearrangements based on 2-fluoroallylic alcohols are presented. Long-chain 2-fluoroallylic alcohols were converted to corresponding N-unsubstituted carbamates by treatment with trichloroacetyl isocyanate. Dehydration using trifluoroacetic anhydride in the presence of triethylamine formed intermediate allylic cyanates, which immediately underwent sigmatropic rearrangement to fluorinated allyl isocyanates. Without isolation the latter delivered fluorinated ureas by addition of amines. The thiocyanate to isothiocyanate rearrangements started from the same fluorinated allylic alcohols, which were first converted to mesylates. Heating in THF with potassium thiocyanate led to fluorinated allyl isothiocyanates, via [3,3]-sigmatropic rearrangement of intermediate allyl thiocyanates. The formed products were further reacted with amines to fluorinated thioureas.

  17. Determination of Carbonyl Functional Groups in Bio-oils by Potentiometric Titration: The Faix Method

    Energy Technology Data Exchange (ETDEWEB)

    Black, Stuart; Ferrell, Jack R.


    Carbonyl compounds present in bio-oils are known to be responsible for bio-oil property changes upon storage and during upgrading. Specifically, carbonyls cause an increase in viscosity (often referred to as 'aging') during storage of bio-oils. As such, carbonyl content has previously been used as a method of tracking bio-oil aging and condensation reactions with less variability than viscosity measurements. Additionally, carbonyls are also responsible for coke formation in bio-oil upgrading processes. Given the importance of carbonyls in bio-oils, accurate analytical methods for their quantification are very important for the bio-oil community. Potentiometric titration methods based on carbonyl oximation have long been used for the determination of carbonyl content in pyrolysis bio-oils. Here, we present a modification of the traditional carbonyl oximation procedures that results in less reaction time, smaller sample size, higher precision, and more accurate carbonyl determinations. While traditional carbonyl oximation methods occur at room temperature, the Faix method presented here occurs at an elevated temperature of 80 degrees C.

  18. [Chemical Characteristics and Sources of Atmospheric Carbonyls During the 2014 Beijing APEC]. (United States)

    He, Xiao-lang; Tan, Ji-hua; Guo, Song-jun; Ma, Yong-liang; He, Ke-bin


    Pollution characteristic and variation trend of atmospheric carbonyls were investigated in November during the 2014 Beijing APEC. Formaldehyde, acetaldehyde and acetone were the dominant carbonyls, accounting for 82.66% of total carbonyls, and especially, formaldehyde accounted for 40.12% of total carbonyls. Atmospheric concentrations of total carbonyls decreased by around 64.10% after the clean air policy was carried out during the Beijing APEC, and the variation trend of carbonyls showed a similar pattern to those of other pollutants like PM₂.₅ during the APEC. Strong correlations (R² of 0.67-0.98) were observed among formaldehyde, acetaldehyde, acetone and total carbonyls during and after the APEC, indicating that they had similar sources; however, poor correlations (R² of -0.11-0.42 and 0.16-0.94, respectively) were observed before the APEC, implying different emission sources for ambient carbonyls. The calculated ratios of C1/C2, C2/C3 and OC/EC indicated that both vehicles and coal emissions were responsible for atmospheric carbonyls before the APEC, and emissions from coal burning were the major contributor to atmospheric carbonyls during and after the APEC, especially after the APEC.

  19. Indoor carbonyl compounds in an academic building in Beijing, China: concentrations and influencing factors

    Institute of Scientific and Technical Information of China (English)

    Chuanjia JIANG; Pengyi ZHANG


    Carbonyl compounds in indoor air are of great concern for their adverse health effects. Between February and May, 2009, concentrations of 13 carbonyl compounds were measured in an academic building in Beijing, China. Total concentration of the detected carbonyls ranged from 20.7 to 189.1, and among them acetone and formaldehyde were the most abundant, with mean concentrations of 26.4 and 22.6gg.m-3, respectively. Average indoor concentrations of other carbonyls were below I 0 gg. m~3. Principal component analysis identified a combined effect of common indoor carbonyl sources and ventilation on indoor carbonyl levels. Diurnal variations of the carbonyl compounds were investigated in one office room, and carbonyl concentrations tended to be lower in the daytime than at night, due to enhanced ventilation. Average concentrations of carbonyl compounds in the office room were generally higher in early May than in late February, indicating the influence of temperature. Carbo- nyl source emission rates from both the room and human occupants were estimated during two lectures, based on one-compartment mass balance model. The influence of human occupants on indoor carbonyl concentrations varies with environmental conditions, and may become signifi- cant in the case of a large human occupancy.

  20. Determination of Carbonyl Functional Groups in Bio-oils by Potentiometric Titration: The Faix Method. (United States)

    Black, Stuart; Ferrell, Jack R


    Carbonyl compounds present in bio-oils are known to be responsible for bio-oil property changes upon storage and during upgrading. Specifically, carbonyls cause an increase in viscosity (often referred to as 'aging') during storage of bio-oils. As such, carbonyl content has previously been used as a method of tracking bio-oil aging and condensation reactions with less variability than viscosity measurements. Additionally, carbonyls are also responsible for coke formation in bio-oil upgrading processes. Given the importance of carbonyls in bio-oils, accurate analytical methods for their quantification are very important for the bio-oil community. Potentiometric titration methods based on carbonyl oximation have long been used for the determination of carbonyl content in pyrolysis bio-oils. Here, we present a modification of the traditional carbonyl oximation procedures that results in less reaction time, smaller sample size, higher precision, and more accurate carbonyl determinations. While traditional carbonyl oximation methods occur at room temperature, the Faix method presented here occurs at an elevated temperature of 80 °C.

  1. Zinc mediated domino elimination-alkylation of methyl 5-iodopentofuranosides

    DEFF Research Database (Denmark)

    Hyldtoft, Lene; Poulsen, Carina Storm; Madsen, Robert


    5-Iodopentofuranosides are converted with zinc and allyl/propargyl bromide into dienes/enynes which are further used in carbohydrate annulation reactions.......5-Iodopentofuranosides are converted with zinc and allyl/propargyl bromide into dienes/enynes which are further used in carbohydrate annulation reactions....

  2. Role of allyl group in the hydroxyl and peroxyl radical scavenging activity of S-allylcysteine. (United States)

    Maldonado, Perla D; Alvarez-Idaboy, J Raúl; Aguilar-González, Adriana; Lira-Rocha, Alfonso; Jung-Cook, Helgi; Medina-Campos, Omar Noel; Pedraza-Chaverrí, José; Galano, Annia


    S-Allylcysteine (SAC) is the most abundant compound in aged garlic extracts, and its antioxidant properties have been demonstrated. It is known that SAC is able to scavenge different reactive species including hydroxyl radical (•OH), although its potential ability to scavenge peroxyl radical (ROO•) has not been explored. In this work the ability of SAC to scavenge ROO• was evaluated, as well as the role of the allyl group (-S-CH(2)-CH═CH(2)) in its free radical scavenging activity. Two derived compounds of SAC were prepared: S-benzylcysteine (SBC) and S-propylcysteine (SPC). Their abilities to scavenge •OH and ROO• were measured. A computational analysis was performed to elucidate the mechanism by which these compounds scavenge •OH and ROO•. SAC was able to scavenge •OH and ROO•, in a concentration-dependent way. Such activity was significantly ameliorated when the allyl group was replaced by benzyl or propyl groups. It was shown for the first time that SAC is able to scavenge ROO•.

  3. Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo (United States)

    Shakoori, Alireza; Bremner, John B; Abdel-Hamid, Mohammed K; Willis, Anthony C; Haritakun, Rachada


    Summary Diversity-directed synthesis based on the cascade allylation chemistry of indigo, with its embedded 2,2’-diindolic core, has resulted in rapid access to new examples of the hydroxy-8a,13-dihydroazepino[1,2-a:3,4-b']diindol-14(8H)-one skeleton in up to 51% yield. Additionally a derivative of the novel bridged heterocycle 7,8-dihydro-6H-6,8a-epoxyazepino[1,2-a:3,4-b']diindol-14(13H)-one was produced when the olefin of the allylic substrate was terminally disubstituted. Further optimisation also produced viable one-pot syntheses of derivatives of the spiro(indoline-2,9'-pyrido[1,2-a]indol)-3-one (65%) and pyrido[1,2,3-s,t]indolo[1,2-a]azepino[3,4-b]indol-17-one (72%) heterocyclic systems. Ring-closing metathesis of the N,O-diallylic spiro structure and subsequent Claisen rearrangement gave rise to the new (1R,8aS,17aS)-rel-1,2-dihydro-1-vinyl-8H,17H,9H-benz[2',3']pyrrolizino[1',7a':2,3]pyrido[1,2-a]indole-8,17-(2H,9H)-dione heterocyclic system. PMID:25977722

  4. Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo

    Directory of Open Access Journals (Sweden)

    Alireza Shakoori


    Full Text Available Diversity-directed synthesis based on the cascade allylation chemistry of indigo, with its embedded 2,2’-diindolic core, has resulted in rapid access to new examples of the hydroxy-8a,13-dihydroazepino[1,2-a:3,4-b']diindol-14(8H-one skeleton in up to 51% yield. Additionally a derivative of the novel bridged heterocycle 7,8-dihydro-6H-6,8a-epoxyazepino[1,2-a:3,4-b']diindol-14(13H-one was produced when the olefin of the allylic substrate was terminally disubstituted. Further optimisation also produced viable one-pot syntheses of derivatives of the spiro(indoline-2,9'-pyrido[1,2-a]indol-3-one (65% and pyrido[1,2,3-s,t]indolo[1,2-a]azepino[3,4-b]indol-17-one (72% heterocyclic systems. Ring-closing metathesis of the N,O-diallylic spiro structure and subsequent Claisen rearrangement gave rise to the new (1R,8aS,17aS-rel-1,2-dihydro-1-vinyl-8H,17H,9H-benz[2',3']pyrrolizino[1',7a':2,3]pyrido[1,2-a]indole-8,17-(2H,9H-dione heterocyclic system.

  5. Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

    Directory of Open Access Journals (Sweden)

    David Porter


    Full Text Available Iron(II complexes of the tetradentate amines tris(2-pyridylmethylamine (TPA and N,N′-bis(2-pyridylmethyl-N,N′-dimethylethane-1,2-diamine (BPMEN are established catalysts of C–O bond formation, oxidising hydrocarbon substrates via hydroxylation, epoxidation and dihydroxylation pathways. Herein we report the capacity of these catalysts to promote C–N bond formation, via allylic amination of alkenes. The combination of N-Boc-hydroxylamine with either FeTPA (1 mol % or FeBPMEN (10 mol % converts cyclohexene to the allylic hydroxylamine (tert-butyl cyclohex-2-en-1-yl(hydroxycarbamate in moderate yields. Spectroscopic studies and trapping experiments suggest the reaction proceeds via a nitroso–ene mechanism, with involvement of a free N-Boc-nitroso intermediate. Asymmetric induction is not observed using the chiral tetramine ligand (+-(2R,2′R-1,1′-bis(2-pyridylmethyl-2,2′-bipyrrolidine ((R,R′-PDP.

  6. Mechanism of the cobalt oxazoline palladacycle (COP)-catalyzed asymmetric synthesis of allylic esters. (United States)

    Cannon, Jeffrey S; Kirsch, Stefan F; Overman, Larry E; Sneddon, Helen F


    The catalytic enantioselective S(N)2' displacement of (Z)-allylic trichloroacetimidates catalyzed by the palladium(II) complex [COP-OAc](2) is a broadly useful method for the asymmetric synthesis of chiral branched allylic esters. A variety of experiments aimed at elucidating the nature of the catalytic mechanism and its rate- and enantiodetermining steps are reported. Key findings include the following: (a) the demonstration that a variety of bridged-dipalladium complexes are present and constitute resting states of the COP catalyst (however, monomeric palladium(II) complexes are likely involved in the catalytic cycle); (b) labeling experiments establishing that the reaction proceeds in an overall antarafacial fashion; (c) secondary deuterium kinetic isotope effects that suggest substantial rehybridization at both C1 and C3 in the rate-limiting step; and (d) DFT computational studies (B3-LYP/def2-TZVP) that provide evidence for bidentate substrate-bound intermediates and an anti-oxypalladation/syn-deoxypalladation pathway. These results are consistent with a novel mechanism in which chelation of the imidate nitrogen to form a cationic palladium(II) intermediate activates the alkene for attack by external carboxylate in the enantiodetermining step. Computational modeling of the transition-state structure for the acyloxy palladation step provides a model for enantioinduction.

  7. Determination of Carbonyl Compounds in Cigarette Mainstream Smoke. The CORESTA 2010 Collaborative Study and Recommended Method

    Directory of Open Access Journals (Sweden)

    Intorp M


    Full Text Available A recommended method has been developed and published by CORESTA, applicable to the quantification of selected carbonyl compounds (acetaldehyde, formaldehyde, acetone, acrolein, methyl ethyl ketone, crotonaldehyde, propionaldehyde and butyraldehyde in cigarette mainstream smoke. The method involved smoke collection in impinger traps, derivatisation of carbonyls with 2,4-dinitrophenylhydrazine (DNPH, separation of carbonyl hydrazones by reversed phase high performance liquid chromatography and detection by ultra violet or diode array.

  8. Does a hydrogen bonded complex with dual contacts show synergism? A matrix isolation infrared and ab-initio study of propargyl alcohol-water complex (United States)

    Saini, Jyoti; Viswanathan, K. S.


    When hydrogen bonded complexes are formed with more than one contact, the question arises if these multiple contacts operate synergistically. Propargyl alcohol-H2O complex presents a good case study to address this question, which is discussed in this work. Complexes of propargyl alcohol (PA) and H2O were studied experimentally using matrix isolation infrared spectroscopy, which was supported by quantum chemical computations performed at the M06-2X and MP2 level of theories, using 6-311++G (d,p) and aug-cc-pVDZ basis sets. A 1:1 PA-H2O complex was identified in the experiments and corroborated by our computations, where the PA was in the gauche conformation. This complex, which was a global minimum, showed dual interactions, one of which was an n-σ interaction between the O-H group of PA and the O of H2O, while the second was a H···​π contact between the O-H group of H2O and the π system of PA. We explored if the two interactions in the 1:1 complex exhibited synergism. We finally argue that the two interactions showed antagonism rather than synergism. Our computations indicated three other local minima for the 1:1 complexes; though these local minima were not identified in our experiments. Atoms-in-molecules and energy decomposition analysis executed through LMO-EDA were also performed to understand the nature of intermolecular interactions in the PA-H2O complexes. We have also revisited the problem of conformations of PA, with a view to understanding the reasons for gauche conformational preferences in PA.

  9. Two-dimensional gel electrophoretic detection of protein carbonyls derivatized with biotin-hydrazide. (United States)

    Wu, Jinzi; Luo, Xiaoting; Jing, Siqun; Yan, Liang-Jun


    Protein carbonyls are protein oxidation products that are often used to measure the magnitude of protein oxidative damage induced by reactive oxygen or reactive nitrogen species. Protein carbonyls have been found to be elevated during aging and in age-related diseases such as stroke, diabetes, and neurodegenerative diseases. In the present article, we provide detailed protocols for detection of mitochondrial protein carbonyls labeled with biotin-hydrazide followed by 2-dimensional isoelectric focusing (IEF)/SDS-PAGE and Western blotting probed with horse-radish peroxidase-conjugated streptavidin. The presented procedures can also be modified for detection of carbonylation of non-mitochondrial proteins.

  10. A biotin enrichment strategy identifies novel carbonylated amino acids in proteins from human plasma

    DEFF Research Database (Denmark)

    Havelund, Jesper F.; Wojdyla, Katarzyna; Davies, Michael J.


    Protein carbonylation is an irreversible protein oxidation correlated with oxidative stress, various diseases and ageing. Here we describe a peptide-centric approach for identification and characterisation of up to 14 different types of carbonylated amino acids in proteins. The modified residues...... in vitro metal ion-catalysed oxidation. Furthermore, we assigned 133 carbonylated sites in 36 proteins in native human plasma protein samples. The optimised workflow enabled detection of 10 hitherto undetected types of carbonylated amino acids in proteins: aldehyde and ketone modifications of leucine...

  11. Bis-propargyl thermosets (United States)

    Douglas, Elliot P.; Langlois, David A.; Benicewicz, Brian C.


    The present invention provides (1) curable bispropargyl-containing monomers represented by the formula: B.sup.1 --A.sup.1.sub.m --R--A.sup.2.sub.n --B.sup.2 wherein R is a radical selected from the group consisting of 1,4-phenylene, 4,4'-biphenyl, 2,6-naphthalene, --C.sub.6 H.sub.4 --CR.sup.2 .dbd.CR.sup.2 --C.sub.6 H.sub.4 -- wherein R.sup.2 is H or CH.sub.3, and the same where said groups contain one or more substituents selected from the group consisting of halo, nitro, lower alkyl, lower alkoxy, fluoroalkyl or fluoroalkoxy, A.sup.1 and A.sup.2 are selected from the group consisting of --C.sub.6 H.sub.4 --C(O)--O-- and --C.sub.6 H.sub.4 --O--C(O)--, m and n are 0 or 1, m+n is 0, 1 or 2, and B.sup.1 and B.sup.2 are --OCH.sub.2 --C.tbd.C--H, (2) thermoset compositions comprised of cured segments derived from monomers represented by the formula: B.sup.1 --A.sup.1.sub.m --R--A.sup.2.sub.n --B.sup.2 as described above, and (3) curable blends of at least two of the monomers.

  12. Asymmetric allylic alkylation in combination with ring-closing metathesis for the preparation of chiral N-heterocycles

    NARCIS (Netherlands)

    Teichert, Johannes F.; Zhang, Suyan; Zijl, Anthoni W. van; Slaa, Jan Willem; Minnaard, Adriaan J.; Feringa, Bernard


    Asymmetric copper-catalyzed allylic substitution with methylmagnesium bromide is employed in combination with ring-closing olefin metathesis or ene-yne metathesis to achieve the synthesis of chiral, unsaturated nitrogen heterocycles. The resulting six- to eight-membered chiral heterocycles are acces

  13. The NBS Reaction: A Simple Explanation for the Predominance of Allylic Substitution over Olefin Addition by Bromine at Low Concentrations. (United States)

    Wamser, Carl C.; Scott, Lawrence T.


    Examines mechanisms related to use of N-bromosuccinimide (NBS) for bromination at an allylic position. Also presents derived rate laws for three possible reactions of molecular bromine with an alkene: (1) free radical substitution; (2) free radical addition; and (3) electrophilic addition. (JN)

  14. Synthesis of novel chiral phosphine-triazine ligand derived from α-phenylethylamine for Pd-catalyzed asymmetric allylic alkylation

    Institute of Scientific and Technical Information of China (English)

    Jia Di Huang; Xiang Ping Hu; Zhuo Zheng


    A novel chiral phosphine-triazine ligand was synthesized from chiral model reaction of Pd-catalyzed allylic alkylation of rac-l,3-diphenylprop-2-en-l-yl pivalate with dimethyl malonate, good enantioselectivity (90% e.e.) was obtained by using this ligand.

  15. New chiral N, S-ligands with Thiophenyl at Benzylic Position. Palladium(Ⅱ)-catalyzed Enantioselective Allylic Alkylation

    Institute of Scientific and Technical Information of China (English)

    WU,Hao(吴昊); WU,Xun-Wei(巫循伟); HOU,Xue-Long(侯雪龙); DAI,Li-Xin(戴立信); WANG,Quan-Rui(王全瑞)


    New chiral N, S-ligands with oxazoline and thiphenyl substituents at benzene ring and benzylic position have been prepared and applied in palladium-catalyzed asymmetric allylic alkylation reaction to provide the product with high yield and entantioselectivity (82%-93% ee).

  16. Antimicrobial activity of allyl isothiocyanate used to coat biodegradable composite films as affected by storage and handling conditions (United States)

    We evaluated the effects of storage and handling conditions on the antimicrobial activity of biodegradable composite films (polylactic acid and sugar beet pulp) coated with allyl isothiocyanate (AIT). Polylactic acid (PLA) and chitosan were incorporated with AIT and coated on one side of the film. T...

  17. Spectra of carbanions formed from allyl cyanide during isomerization in zeolite NaY-FAU with strong basic sites (United States)

    Hannus, István; Förster, Horst; Tasi, Gyula; Kiricsi, Imre; Molnár, Árpád


    Double bond isomerization of allyl cyanide to crotononitrile over a basic zeolite catalyst was monitored by IR and UV-VIS spectroscopy in order to get information on the surface intermediates involved. Due to the spectral changes the occurence of a carbanionic intermediate seems to be highly probable characterized by an absorption at 400 nm.

  18. Phosphine-catalyzed [4 + 1] annulation between α,β-unsaturated imines and allylic carbonates: synthesis of 2-pyrrolines. (United States)

    Tian, Junjun; Zhou, Rong; Sun, Haiyun; Song, Haibin; He, Zhengjie


    In this report, a phosphine-catalyzed [4 + 1] annulation between α,β-unsaturated imines and allylic carbonates is described. This reaction represents the first realization of catalytic [4 + 1] cyclization of 1,3-azadienes with in situ formed phosphorus ylides, which provides highly efficient and diastereoselective synthesis of 2-pyrrolines.

  19. Reactive Carbonyl Species In Vivo: Generation and Dual Biological Effects

    Directory of Open Access Journals (Sweden)

    Halyna M. Semchyshyn


    Full Text Available Reactive carbonyls are widespread species in living organisms and mainly known for their damaging effects. The most abundant reactive carbonyl species (RCS are derived from oxidation of carbohydrates, lipids, and amino acids. Chemical modification of proteins, nucleic acids, and aminophospholipids by RCS results in cytotoxicity and mutagenicity. In addition to their direct toxicity, modification of biomolecules by RCS gives rise to a multitude of adducts and cross links that are increasingly implicated in aging and pathology of a wide range of human diseases. Understanding of the relationship between metabolism of RCS and the development of pathological disorders and diseases may help to develop effective approaches to prevent a number of disorders and diseases. On the other hand, constant persistence of RCS in cells suggests that they perform some useful role in living organisms. The most beneficial effects of RCS are their establishment as regulators of cell signal transduction and gene expression. Since RCS can modulate different biological processes, new tools are required to decipher the precise mechanisms underlying dual effects of RCS.

  20. Glutathione Adduct Patterns of Michael-Acceptor Carbonyls. (United States)

    Slawik, Christian; Rickmeyer, Christiane; Brehm, Martin; Böhme, Alexander; Schüürmann, Gerrit


    Glutathione (GSH) has so far been considered to facilitate detoxification of soft organic electrophiles through covalent binding at its cysteine (Cys) thiol group, followed by stepwise catalyzed degradation and eventual elimination along the mercapturic acid pathway. Here we show that in contrast to expectation from HSAB theory, Michael-acceptor ketones, aldehydes and esters may form also single, double and triple adducts with GSH involving β-carbon attack at the much harder N-terminus of the γ-glutamyl (Glu) unit of GSH. In particular, formation of the GSH-N single adduct contradicts the traditional view that S alkylation always forms the initial reaction of GSH with Michael-acceptor carbonyls. To this end, chemoassay analyses of the adduct formation of GSH with nine α,β-unsaturated carbonyls employing high performance liquid chromatography and tandem mass spectrometry have been performed. Besides enriching the GSH adductome and potential biomarker applications, electrophilic N-terminus functio-nalization is likely to impair GSH homeostasis substantially through blocking the γ-glutamyl transferase catalysis of the first breakdown step of modified GSH, and thus its timely reconstitution. The discussion includes a comparison with cyclic adducts of GSH and furan metabolites as reported in literature, and quantum chemically calculated thermodynamics of hard-hard, hard-soft and soft-soft adducts.

  1. IRC analysis of methanol carbonylation reaction catalyzed by rhodium complex

    Institute of Scientific and Technical Information of China (English)

    HAO Maorong; FENG Wenlin; JI Yongqiang; LEI Ming


    In the reaction cycle for methanol carbonylation catalyzed by Rh complex, the structure geometries of the reactant, intermediates, transition states and product of each elemental reaction have been studied by using the energy gradient method at HF/LANL2DZ level, and the changes of their potential profiles have also been calculated. Through IRC analyses of the transition states for each elemental reaction, it is confirmed that the various structure geometries obtained are stationary points on the cycle reaction pathway of methanol carbonylation catalyzed by Rh complex, and the changes are given in energies and structure geometries of the reactant molecules along the reaction pathway of lowest energy. It has been proposed that the geometrical conversions of intermediates play an important role during the cycle reaction. Through analyses of structure geometries, it has been suggested that, in addition to cis- and trans- structure exchange linkage of catalysis reactive species, the two pathways, cis- and trans-cata- lyzed cycle reactions, can also be linked through geometrical conversion of intermediates, of which the activation energy is 49.79 kJ/mol. Moreover, the reductive elimination elemental reaction may be neither cis-cycle nor trans- one, showing that the cycle reaction can be achieved through various pathways. However different the pathway, the oxidative addition elemental reaction of CH3I is the rate-controlling step.

  2. Transition-metal-catalyzed carbonylation reactions of olefins and alkynes: a personal account. (United States)

    Wu, Xiao-Feng; Fang, Xianjie; Wu, Lipeng; Jackstell, Ralf; Neumann, Helfried; Beller, Matthias


    Carbon monoxide was discovered and identified in the 18th century. Since the first applications in industry 80 years ago, academic and industrial laboratories have broadly explored CO's use in chemical reactions. Today organic chemists routinely employ CO in organic chemistry to synthesize all kinds of carbonyl compounds. Despite all these achievements and a century of carbonylation catalysis, many important research questions and challenges remain. Notably, apart from academic developments, industry applies carbonylation reactions with CO on bulk scale. In fact, today the largest applications of homogeneous catalysis (regarding scale) are carbonylation reactions, especially hydroformylations. In addition, the vast majority of acetic acid is produced via carbonylation of methanol (Monsanto or Cativa process). The carbonylation of olefins/alkynes with nucleophiles, such as alcohols and amines, represent another important type of such reactions. In this Account, we discuss our work on various carbonylations of unsaturated compounds and related reactions. Rhodium-catalyzed isomerization and hydroformylation reactions of internal olefins provide straightforward access to higher value aldehydes. Catalytic hydroaminomethylations offer an ideal way to synthesize substituted amines and even heterocycles directly. More recently, our group has also developed so-called alternative metal catalysts based on iridium, ruthenium, and iron. What about the future of carbonylation reactions? CO is already one of the most versatile C1 building blocks for organic synthesis and is widely used in industry. However, because of CO's high toxicity and gaseous nature, organic chemists are often reluctant to apply carbonylations more frequently. In addition, new regulations have recently made the transportation of carbon monoxide more difficult. Hence, researchers will need to develop and more frequently use practical and benign CO-generating reagents. Apart from formates, alcohols, and metal

  3. A step-by-step protocol for assaying protein carbonylation in biological samples. (United States)

    Colombo, Graziano; Clerici, Marco; Garavaglia, Maria Elisa; Giustarini, Daniela; Rossi, Ranieri; Milzani, Aldo; Dalle-Donne, Isabella


    Protein carbonylation represents the most frequent and usually irreversible oxidative modification affecting proteins. This modification is chemically stable and this feature is particularly important for storage and detection of carbonylated proteins. Many biochemical and analytical methods have been developed during the last thirty years to assay protein carbonylation. The most successful method consists on protein carbonyl (PCO) derivatization with 2,4-dinitrophenylhydrazine (DNPH) and consequent spectrophotometric assay. This assay allows a global quantification of PCO content due to the ability of DNPH to react with carbonyl giving rise to an adduct able to absorb at 366 nm. Similar approaches were also developed employing chromatographic separation, in particular HPLC, and parallel detection of absorbing adducts. Subsequently, immunological techniques, such as Western immunoblot or ELISA, have been developed leading to an increase of sensitivity in protein carbonylation detection. Currently, they are widely employed to evaluate change in total protein carbonylation and eventually to highlight the specific proteins undergoing selective oxidation. In the last decade, many mass spectrometry (MS) approaches have been developed for the identification of the carbonylated proteins and the relative amino acid residues modified to carbonyl derivatives. Although these MS methods are much more focused and detailed due to their ability to identify the amino acid residues undergoing carbonylation, they still require too expensive equipments and, therefore, are limited in distribution. In this protocol paper, we summarise and comment on the most diffuse protocols that a standard laboratory can employ to assess protein carbonylation; in particular, we describe step-by-step the different protocols, adding suggestions coming from our on-bench experience.

  4. Influences of characteristic meteorological conditions on atmospheric carbonyls in Beijing, China (United States)

    Pang, Xiaobing; Mu, Yujing; Lee, Xinqing; Zhang, Yujie; Xu, Zhu


    Atmospheric pollutants are controlled not only by their production rates but also by meteorological conditions. The influences of dust storm, sauna weather (haze with high temperature and high humidity), wet precipitation and wind speed on atmospheric carbonyls in Beijing were investigated. During a severe dust episode (April 17, 2006), the mixing ratios of carbonyls were significantly elevated to 13-27 ppbV from 7 to 13 ppbV in the previous non-dust days (April 15 and 16) with the increasing extents of 38-154%. The accumulating effect and the lower photolysis rate in the dust day may be responsible for the increases of carbonyls' levels. Additionally, the contribution from heterogeneous reactions occurring on dust particles to formaldehyde and acetaldehyde cannot be ruled out. During the period of typical sauna weather, the concentrations of atmospheric carbonyls increased to 18-60 ppbV from 10 to 17 ppbV before the sauna days. The air mass over Beijing during the sauna days was controlled by a subtropical anticyclone and the boundary layer became quite stable, which was beneficial to the rapid accumulation of air pollutants including carbonyls. Wet precipitation was found to be an effective removal process to the atmospheric carbonyls. After one-hour of rain in summer, the total concentrations of atmospheric carbonyls decreased to less than half of that before the rainfall. The similar temporal varying patterns of carbonyls and inorganic ions in rainwater indicated that carbonyls were mainly washed out from the atmosphere into rainwater as inorganic ions were. Strong wind could evidently dilute atmospheric carbonyls and a negative correlation was found between wind speeds and the concentrations of carbonyls in spring in Beijing.

  5. The Reaction of Allyl Isothiocyanate with Hydroxyl/Water and β-Cyclodextrin Using Ultraviolet Spectrometry

    Directory of Open Access Journals (Sweden)

    Zi-Tao Jiang


    Full Text Available The reaction of allyl isothiocyanate (AITC with hydroxyl/water and β-cyclodextrin (β-CD in different acidic-alkaline media has been investigated by ultraviolet spectrometry. The kinetic parameters of the reaction were measured. It was found that after AITC translating into thiourea, the absorption peak shifted from 240 to 226 nm and the molar absorptivity increased about 16 times. The reaction can be seen as a pseudo first order reaction because the concentration of hydroxyl was constant. β-CD can inhibit the reaction of AITC with hydroxyl/water, i.e. the hydrolysis of AITC. The formation constant (Ka and thermodynamic parameters of the complex reaction were calculated. Ka decreased with the increase of temperature. The experimental results indicated that the inclusive process was an exothermic and enthalpy-driven process accompanied with a negative entropic contribution.

  6. An Efficient Amide-Aldehyde-Alkene Condensation: Synthesis for the N-Allyl Amides. (United States)

    Quan, Zheng-Jun; Wang, Xi-Cun


    The allylamine skeleton represents a significant class of biologically active nitrogen compounds that are found in various natural products and drugs with well-recognized pharmacological properties. In this personal account, we will briefly discuss the synthesis of allylamine skeletons. We will focus on showing a general protocol for Lewis acid-catalyzed N-allylation of electron-poor N-heterocyclic amides and sulfonamide via an amide-aldehyde-alkene condensation reaction. The substrate scope with respect to N-heterocyclic amides, aldehydes, and alkenes will be discussed. This method is also capable of preparing the Naftifine motif from N-methyl-1-naphthamide or methyl (naphthalene-1-ylmethyl)carbamate, with paraformaldehyde and styrene in a one-pot manner.

  7. Enantioselective construction of quaternary N-heterocycles by palladium-catalysed decarboxylative allylic alkylation of lactams

    KAUST Repository

    Behenna, Douglas C.


    The enantioselective synthesis of nitrogen-containing heterocycles (N-heterocycles) represents a substantial chemical research effort and resonates across numerous disciplines, including the total synthesis of natural products and medicinal chemistry. In this Article, we describe the highly enantioselective palladium-catalysed decarboxylative allylic alkylation of readily available lactams to form 3,3-disubstituted pyrrolidinones, piperidinones, caprolactams and structurally related lactams. Given the prevalence of quaternary N-heterocycles in biologically active alkaloids and pharmaceutical agents, we envisage that our method will provide a synthetic entry into the de novo asymmetric synthesis of such structures. As an entry for these investigations we demonstrate how the described catalysis affords enantiopure quaternary lactams that intercept synthetic intermediates previously used in the synthesis of the Aspidosperma alkaloids quebrachamine and rhazinilam, but that were previously only available by chiral auxiliary approaches or as racemic mixtures. © 2012 Macmillan Publishers Limited. All rights reserved.

  8. Low-temperature Electrodeposition of Aluminium from Lewis Acidic 1-Allyl-3-methylimidazolium Chloroaluminate Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    郑勇; 张锁江; 吕兴梅; 王倩; 左勇; 刘恋


    Lewis acidic 1-allyl-3-methylimidazolium chloroaluminate ionic liquids were used as promising electrolytes in the low-temperature electrodeposition of aluminium. Systematic studies on deposition process have been performed by cYClic voltammetry and chronoamperometry. The surface morphology and X-ray diffraction (XRD) patterns of deposits prepared at different experimental conditions were also investigated. It was shown that the nucleation density and growth rate of crystallites had a great effect on the structure of aluminium deposited. The crys- tallographic orientation of deposits was mainly influenced by temperature and current density. Smooth, dense and well adherent aluminium coatings were obtained on copper substrates at 10-25^-2 and 313.2-353.2 K. More- over, the current efficiency of deposition and purity of aluminium have been significantly improved, demonstrating that the ionic liquids tested have a prospectful potential in electroplating and electrorefining of aluminium.

  9. Structural characteristics of green tea catechins for formation of protein carbonyl in human serum albumin. (United States)

    Ishii, Takeshi; Mori, Taiki; Ichikawa, Tatsuya; Kaku, Maiko; Kusaka, Koji; Uekusa, Yoshinori; Akagawa, Mitsugu; Aihara, Yoshiyuki; Furuta, Takumi; Wakimoto, Toshiyuki; Kan, Toshiyuki; Nakayama, Tsutomu


    Catechins are polyphenolic antioxidants found in green tea leaves. Recent studies have reported that various polyphenolic compounds, including catechins, cause protein carbonyl formation in proteins via their pro-oxidant actions. In this study, we evaluate the formation of protein carbonyl in human serum albumin (HSA) by tea catechins and investigate the relationship between catechin chemical structure and its pro-oxidant property. To assess the formation of protein carbonyl in HSA, HSA was incubated with four individual catechins under physiological conditions to generate biotin-LC-hydrazide labeled protein carbonyls. Comparison of catechins using Western blotting revealed that the formation of protein carbonyl in HSA was higher for pyrogallol-type catechins than the corresponding catechol-type catechins. In addition, the formation of protein carbonyl was also found to be higher for the catechins having a galloyl group than the corresponding catechins lacking a galloyl group. The importance of the pyrogallol structural motif in the B-ring and the galloyl group was confirmed using methylated catechins and phenolic acids. These results indicate that the most important structural element contributing to the formation of protein carbonyl in HSA by tea catechins is the pyrogallol structural motif in the B-ring, followed by the galloyl group. The oxidation stability and binding affinity of tea catechins with proteins are responsible for the formation of protein carbonyl, and consequently the difference in these properties of each catechin may contribute to the magnitude of their biological activities.

  10. Iron(III)-Catalyzed Ring-Closing Carbonyl-Olefin Metathesis. (United States)

    Saá, Carlos


    Recent developments in catalytic carbonyl-olefin metathesis are summarized in this Highlight. Schindler and co-workers have reported that the environmentally benign FeCl3 catalyst promotes ring-closing carbonyl-olefin metathesis (RCCOM) in high yield under very mild conditions.

  11. Preparation and microwave shielding property of silver-coated carbonyl iron powder

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Xiao Guo, E-mail: [School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong (China); Ren, Hao [Guangzhou Research Institute of O-M-E Technology, Guangzhou 510006, Guangdong (China); Zhang, Hai Yan [School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, Guangdong (China)


    Highlights: • The silver-coated carbonyl iron powder is prepared by the electroless plating process. • The silver-coated carbonyl iron powder is a new kind of conductive filler. • The reflection and absorption dominate the shielding mechanism of the prepared powder. • Increasing the thickness of electroconductive adhesive will increase the SE. - Abstract: Electroless silver coating of carbonyl iron powder is demonstrated in the present investigation. The carbonyl iron powders are characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD) before and after the coating process. The relatively uniform and continuous silver coating is obtained under the given coating conditions. In this paper, the electromagnetic interference (EMI) shielding mechanism of the silver-coated carbonyl iron powder is suggested. The reflection of silver coating and absorption of carbonyl iron powder dominate the shielding mechanism of the silver-coated carbonyl iron powder. The silver-coated carbonyl iron powders are used as conductive filler in electroconductive adhesive for electromagnetic interference shielding applications. The effect of the thickness of electroconductive adhesive on the shielding effectiveness (SE) is investigated. The results indicate that the SE increases obviously with the increase of the thickness of electroconductive adhesive. The SE of the electroconductive adhesive with 0.35 mm thickness is above 38 dB across the tested frequency range.

  12. Decarboxylative-coupling of allyl acetate catalyzed by group 10 organometallics, [(phen)M(CH3)]+. (United States)

    Woolley, Matthew; Ariafard, Alireza; Khairallah, George N; Kwan, Kim Hong-Yin; Donnelly, Paul S; White, Jonathan M; Canty, Allan J; Yates, Brian F; O'Hair, Richard A J


    Gas-phase carbon-carbon bond forming reactions, catalyzed by group 10 metal acetate cations [(phen)M(O2CCH3)](+) (where M = Ni, Pd or Pt) formed via electrospray ionization of metal acetate complexes [(phen)M(O2CCH3)2], were examined using an ion trap mass spectrometer and density functional theory (DFT) calculations. In step 1 of the catalytic cycle, collision induced dissociation (CID) of [(phen)M(O2CCH3)](+) yields the organometallic complex, [(phen)M(CH3)](+), via decarboxylation. [(phen)M(CH3)](+) reacts with allyl acetate via three competing reactions, with reactivity orders (% reaction efficiencies) established via kinetic modeling. In step 2a, allylic alkylation occurs to give 1-butene and reform metal acetate, [(phen)M(O2CCH3)](+), with Ni (36%) > Pd (28%) > Pt (2%). Adduct formation, [(phen)M(C6H11O2)](+), occurs with Pt (24%) > Pd (21%) > Ni(11%). The major losses upon CID on the adduct, [(phen)M(C6H11O2)](+), are 1-butene for M = Ni and Pd and methane for Pt. Loss of methane only occurs for Pt (10%) to give [(phen)Pt(C5H7O2)](+). The sequences of steps 1 and 2a close a catalytic cycle for decarboxylative carbon-carbon bond coupling. DFT calculations suggest that carbon-carbon bond formation occurs via alkene insertion as the initial step for all three metals, without involving higher oxidation states for the metal centers.

  13. Impact of HVAC filter on indoor air quality in terms of ozone removal and carbonyls generation (United States)

    Lin, Chi-Chi; Chen, Hsuan-Yu


    This study aims at detecting ozone removal rates and corresponding carbonyls generated by ozone reaction with HVAC filters from various building, i.e., shopping mall, school, and office building. Studies were conducted in a small-scale environmental chamber. By examining dust properties including organic carbon proportion and specific surface area of dusts adsorbed on filters along with ozone removal rates and carbonyls generation rate, the relationship among dust properties, ozone removal rates, and carbonyls generation was identified. The results indicate a well-defined positive correlation between ozone removal efficiency and carbonyls generation on filters, as well as a positive correlation among the mass of organic carbon on filters, ozone removal efficiency and carbonyls generations.

  14. Protein carbonylation and metal-catalyzed protein oxidation in a cellular perspective

    DEFF Research Database (Denmark)

    Møller, Ian Max; Rogowska-Wrzesinska, Adelina; Rao, R S P


    Proteins can become oxidatively modified in many different ways, either by direct oxidation of amino acid side chains and protein backbone or indirectly by conjugation with oxidation products of polyunsaturated fatty acids and carbohydrates. While reversible oxidative modifications are thought...... to be relevant in physiological processes, irreversible oxidative modifications are known to contribute to cellular damage and disease. The most well-studied irreversible protein oxidation is carbonylation. In this work we first examine how protein carbonylation occurs via metal-catalyzed oxidation (MCO) in vivo...... and in vitro with an emphasis on cellular metal ion homeostasis and metal binding. We then review proteomic methods currently used for identifying carbonylated proteins and their sites of modification. Finally, we discuss the identified carbonylated proteins and the pattern of carbonylation sites in relation...

  15. Carbonyl mediated conductance through metal bound peptides: a computational study (United States)

    Perrine, Trilisa M.; Dunietz, Barry D.


    Large increases in the conductance of peptides upon binding to metal ions have recently been reported experimentally. The mechanism of the conductance switching is examined computationally. It is suggested that oxidation of the metal ion occurs after binding to the peptide. This is caused by the bias potential placed across the metal-peptide complex. A combination of configurational changes, metal ion involvement and interactions between carbonyl group oxygen atoms and the gold leads are all shown to be necessary for the large improvement in the conductance seen experimentally. Differences in the molecular orbitals of the nickel and copper complexes are noted and serve to explain the variation of the improvement in conductance upon binding to either a nickel or copper ion.

  16. Uptake and conversion of carbonyl sulfide in a lawn soil (United States)

    Liu, Junfeng; Mu, Yujing; Geng, Chunmei; Yu, Yunbo; He, Hong; Zhang, Yuanhang

    Carbonyl sulfide (COS) exchange fluxes between a lawn soil and the atmosphere as well as influencing factors (temperature and water content of soil) were investigated using a static cuvette. The optimal soil temperature and water content for COS consumption were about 298 K and 12.5%, respectively. The converting products of the consumed COS in the lawn soil were researched using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The peaks of gas-phase products of CO2 and surface HCO3-, HS-, SO32-, HSO3-, and SO42- species were observed. The possible mechanism of COS conversion in the lawn soil was discussed. The conversion rates of consumed COS into water-soluble sulfate in the lawn soil were studied by ion chromatography (IC). The experimental results show that about 50% sulfur from the soil consumed COS was eventually converted into water-soluble sulfate.

  17. Direct Vapor Phase Carbonylation of Methanol over NiCl2/C Catalyst

    Institute of Scientific and Technical Information of China (English)


    @@ Introduction The carbonylation of alcohols via homogenous catalysis is important in manufacturing acetic acid and higher carboxylic acids and their esters[1,2]. The main route to produce acetic acid is to make methanol carbonylated by means of the Monsanto and BP process in which a homogeneous rhodium catalyst is used. Although the homogeneous carbonylation of methanol is a highly selective process, it is affected by the disadvantages associated with a highly corrosive reaction medium due to the use of methyl iodide as the promoter, and the difficulty of the product separation[3]. The use of a heterogeneous catalyst seems very interesting and attractive to us[4], especially the direct vapor phase carbonylation of methanol without a halide promoter is of considerable importance and is strong incentive economically. There has, however, been very little success in finding either heterogeneous or homogeneous catalysts that can catalyze the reaction effectively without the addition of a promoter[5,6]. According to the known carbonylation mechanism[7,8], the methyl iodide directly carbonylates with CO to from MeCOI which interacts with methanol(MeOH) to produce methyl acetate(MeCOOMe) and HI, and then MeOH reacts with HI to from CH3I. In fact, this carbonylation reaction is the indirect catalytic carbonylation of methanol[9]. In this work, a novel catalyst for the direct vapor phase carbonylation of methanol without the addition of any halide in the feed as a promoter was investigated. Compared to the known liquid phase methanol carbonylation process, some advantages of this vapor phase reaction are as follows:

  18. On the Nature of the Intermediates and the Role of Chloride Ions in Pd-Catalyzed Allylic Alkylations: Added Insight from Density Functional Theory

    DEFF Research Database (Denmark)

    Fristrup, Peter; Ahlquist, Mårten Sten Gösta; Tanner, David Ackland


    The reactivity of intermediates in palladium-catalyzed allylic alkylation was investigated using DFT (B3LYP) calculations including a PB-SCRF solvation model. In the presence of both phosphine and chloride ligands, the allyl intermediate is in equilibrium between a cationic eta(3)-allylPd complex...... with two phosphine ligands, the corresponding neutral complex with one phosphine and one chloride ligand, and a neutral eta(1)-allylPd complex with one chloride and two phosphine ligands. The eta(1)-complex is unreactive toward nucleophiles. The cationic eta(3)-complex is the intermediate most frequently...... invoked in the title reaction, but in the presence of halides, the neutral, unsymmetrically substituted eta(3)-CoMplex will be formed rapidly from anionic Pd(0) complexes in solution. Since the latter will prefer both leaving group ionization and reaction with nucleophiles in the position trans...

  19. Modular access to vicinally functionalized allylic (thio)morpholinonates and piperidinonates by substrate-controlled annulation of 1,3-azadienes with hexacyclic anhydrides. (United States)

    Braunstein, Hannah; Langevin, Spencer; Khim, Monique; Adamson, Jonathan; Hovenkotter, Katie; Kotlarz, Lindsey; Mansker, Brandon; Beng, Timothy K


    A modular substrate-controlled hexannulation of inherently promiscuous 1,3-azadienes with hexacyclic anhydrides, which affords versatile vicinally functionalized allylic lactams, in high yields, regio- and stereoselectivities is described.

  20. Anti-Amoebic Properties of Carbonyl Thiourea Derivatives

    Directory of Open Access Journals (Sweden)

    Maizatul Akma Ibrahim


    Full Text Available Thiourea derivatives display a broad spectrum of applications in chemistry, various industries, medicines and various other fields. Recently, different thiourea derivatives have been synthesized and explored for their anti-microbial properties. In this study, four carbonyl thiourea derivatives were synthesized and characterized, and then further tested for their anti-amoebic properties on two potential pathogenic species of Acanthamoeba, namely A. castellanii (CCAP 1501/2A and A. polyphaga (CCAP 1501/3A. The results indicate that these newly-synthesized thiourea derivatives are active against both Acanthamoeba species. The IC50 values obtained were in the range of 2.39–8.77 µg·mL‑1 (9.47–30.46 µM for A. castellanii and 3.74–9.30 µg·mL‑1 (14.84–31.91 µM for A. polyphaga. Observations on the amoeba morphology indicated that the compounds caused the reduction of the amoeba size, shortening of their acanthopodia structures, and gave no distinct vacuolar and nuclear structures in the amoeba cells. Meanwhile, fluorescence microscopic observation using acridine orange and propidium iodide (AOPI staining revealed that the synthesized compounds induced compromised-membrane in the amoeba cells. The results of this study proved that these new carbonyl thiourea derivatives, especially compounds M1 and M2 provide potent cytotoxic properties toward pathogenic Acanthamoeba to suggest that they can be developed as new anti-amoebic agents for the treatment of Acanthamoeba keratitis.

  1. Oxidation reaction of 4-allyl-4-hydroperoxy-2-methoxycyclohexa-2,5-dienone in the presence of potassium permanganate without a co-oxidant

    Directory of Open Access Journals (Sweden)

    Mehmet Serdar Gültekin


    Full Text Available 4-Allyl-4-hydroperoxy-2-methoxycyclohexa-2,5-dienone (5 was synthesized by photooxygenation of commercially available Eugenol in the presence of tetraphenylporphyrin (TPP as a singlet oxygen sensitizer. The brief and one-pot syntheses of some natural product skeletons were conducted using the corresponding allylic hydroperoxide at different temperatures (0 oC and room temperature with potassium permanganate (KMnO 4 in mild condition at N 2(g atm.

  2. A convenient and stereoselective synthesis of (Z)-allyl selenides via Sm/TMSCI system-promoted coupling of Baylis-Hillman adducts with diselenides

    Institute of Scientific and Technical Information of China (English)

    LIU Yun-kui; XU Dan-qian; XU Zhen-yuan; ZHANG Yong-min


    A simple and convenient procedure for stereoselective synthesis of (Z)-allyl selenides has been developed by a one-pot reaction of diselenides with Baylis-Hillman adducts in the presence of samarium metal-trimethylsilyl chloride under mild conditions. Presumably, the diselenides are cleaved by Sm/TMSCl system to form selenide anions, which then undergo SN2' substitution of Baylis-Hillman adducts to produce the (Z)-allyl selenides.

  3. Molecular basis of neuroprotective activities of rasagiline and the anti-Alzheimer drug TV3326 [(N-propargyl-(3R)aminoindan-5-YL)-ethyl methyl carbamate]. (United States)

    Youdim, M B; Weinstock, M


    Rasagiline (N-propargyl-1-(R)-aminoindan) is a selective, irreversible monoamine oxidase B (MAO B) inhibitor which has been developed as an anti-Parkinson drug. In controlled monotherapy and as adjunct to L-dopa it has shown anti-Parkinson activity. In cell culture (PC-12 and neuroblastoma SH-SY5Y cells) it exhibits neuroprotective and anti-apoptotic activity against several neurotoxins (SIN-1, MPTP, 6-hydroxydopamine and N-methyl-(R)-salsolinol) and ischemia. In vivo, it reduces the sequelae of traumatic brain injury in mice and speeds their recovery. The neuroprotective activity of rasagaline does not result from MAO B inhibition, since its S-enantiomer, TVP1022, which has 1000-fold weaker MAO inhibitory activity, exhibits similar neuroprotective properties. Introduction of a carbamate moiety into the rasagiline molecule to confer cholinesterase inhibitory activity for the treatment of Alzheimer's disease, resulted in compounds TV3326 [(N-Propargyl-(3R)Aminoindan-5-YL)-Ethyl Methyl Carbamate] and its S-enantiomer TV3279 [(N-Propargyl-(3S)Aminoindan-5-YL)-Ethyl Methyl Carbamate], which retain the neuroprotective activities of rasagiline and TVP1022. They also antagonize scopolamine-induced impairments in spatial memory. In addition, TV3326 exhibits brain-selective MAO A and B inhibitory activity after chronic administration and has antidepressant-like activity in the forced swim test. This is associated with an increase in brain levels of serotonin. The anti-apoptotic activity of these propargylamine-containing derivatives may be related to their ability to delay the opening of voltage-dependent anion channels (VDAC), which are part of the mitochondrial permeability transition pore. The propargylamine moiety is responsible for the increase in the mitochondrial family of Bcl-2 proteins, prevention in the fall in mitochondrial membrane potential, prevention of the activation of caspase 3, and of translocation of glyceraldehyde-3-phosphate dehydrogenase from the


    Institute of Scientific and Technical Information of China (English)

    Rui-qiang Kou; Chao Qu; Zhi-kang Xu; You-yi Xu; Ke Yao


    In this work, the surface properties of novel sugar-containing polymers, α-allyl glucoside (AG)/acrylonitrile (AN)copolymers, were studied by contact angle, protein adsorption and cell adhesion measurements. It was found that the contact angle of the copolymer films decreased from 68° to 30° with the increase of AG content in the copolymer. The adsorption amount of bovine serum albumin (BSA) and the adhesive macrophage onto the film surface also decreased significantly with increasing α-allyl glucoside content from 0 to 42 wt% in the copolymer. These preliminary results reveal that both the hydrophilicity and the biocompatibility of polyacrylonitrile-based membranes could be improved by copolymerizing acrylonitrile with vinyl carbohydrates.

  5. Epoxidation of olefins and allylic alcohols with hydrogen peroxide catalyzed by heteropoly acids in the presence of cetylpyridinium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Okabayashi, Takuji; Yamawaki, Kazumasa; Nishihara, Hideki; Yamada, Hiroshi; Ura, Toshikazu; Ishii, Yasutaka; Ogawa, Masaya


    The epoxidation of olefins and allylic alcohols with aqueous hydrogen peroxide could be achieved in good yield when 12-tungustophosphoric acid(WPA) was used with two phase condition using chloroform as the solvent. From the epoxidation result by 12-molybdophosphoric acid(MPA) and WPA catalysts, epoxidation activity of WPA catalyst was found to be remarkably higher than that of MPA. The rate of epoxidation by heteropoly acids catalyst depended markedly upon the activity of the reaction medium. Epoxidation of allylic alcohols with hydrogen peroxide proceeded under mild conditions, resulting good yield of epoxi-alcohols. Epoxidation of olefins by WPA/cetylpyridium chloride was confirmed to be promoted selectively with cheap and pure hydrogen peroxide, resulting good yield. (3 figs, 2 tabs, 18 refs)

  6. One-pot synthesis of enantiomerically pure N-protected allylic amines from N-protected α-amino esters (United States)

    Silveira-Dorta, Gastón; Álvarez-Méndez, Sergio J; Martín, Víctor S


    Summary An improved protocol for the synthesis of enantiomerically pure allylic amines is reported. N-Protected α-amino esters derived from natural amino acids were submitted to a one-pot tandem reduction–olefination process. The sequential reduction with DIBAL-H at −78 °C and subsequent in situ addition of organophosphorus reagents yielded the corresponding allylic amines without the need to isolate the intermediate aldehyde. This circumvents the problem of instability of the aldehydes. The method tolerates well both Wittig and Horner–Wadsworth–Emmons organophosphorus reagents. A better Z-(dia)stereoselectivity was observed when compared to the previous one-pot method. The (dia)stereoselectivity of the process was affected neither by the reaction solvent nor by the amount of DIBAL-H employed. The method is compatible with the presence of free hydroxy groups as shown with serine and threonine derivatives. PMID:27340486

  7. Crystal structure of (Z-3-allyl-5-(3-bromobenzylidene-2-sulfanylidene-1,3-thiazolidin-4-one

    Directory of Open Access Journals (Sweden)

    Rahhal El Ajlaoui


    Full Text Available In the title compound, C13H10BrNOS2, the rhodanine (systematic name: 2-sulfanylidene-1,3-thiazolidin-4-one and the 3-bromobenzylidene ring systems are inclined slightly, forming a dihedral angle of 5.86 (12°. The rhodanine moiety is linked to an allyl group at the N atom and to the 3-bromobenzylidene ring system. The allyl group, C=C—C, is nearly perpendicular to the mean plane through the rhodanine ring, maling a dihedral angle of 87.2 (5°. In the crystal, molecules are linked by pairs of C—H...O hydrogen bonds, forming inversion dimers with an R22(10 ring motif.

  8. Method for the Determination of Carbonyl Compounds in E-Cigarette Aerosols (United States)

    Flora, Jason W.; Wilkinson, Celeste T.; Wilkinson, James W.; Lipowicz, Peter J.; Skapars, James A.; Anderson, Adam; Miller, John H.


    Low levels of thermal degradation products such as carbonyls (formaldehyde, acetaldehyde, acrolein, crotonaldehyde) have been reported in e-cigarette aerosols. The collection and analysis of e-cigarette aerosol carbonyls are often adapted from methods developed for tobacco cigarette smoke. These methodologies are often not sensitive enough to detect low carbonyl levels in e-cigarette aerosols. One objective of this work was to develop and validate a rapid, selective and sensitive ultra-performance liquid chromatography with mass spectrometry method optimized for analysis of carbonyls in e-cigarette aerosols. Aerosols were trapped in 20-puff collections, 4-s durations, 55-mL volumes, 30-s intervals, square wave puff profiles. Collection apparatus involved a linear smoking machine with Cambridge filter pad followed by a glass impinger containing acidified 2,4-dinitrophenylhydrazine. This method showed limits of quantitation and detection of 0.016 and 0.003 µg puff−1, respectively, and run time of 4 min. Six e-cigarettes were evaluated (five devices each). All contained measurable levels of carbonyls. Levels were mostly well below those in conventional cigarettes. However, for some e-cigarettes, formaldehyde levels were above those for tobacco cigarettes (highest at 14.1 µg puff−1). Temperatures related to carbonyl yields in e-cigarette aerosols were explored to better understand carbonyl formation: formation of formaldehyde is low at temperatures below 350°C. PMID:28087758

  9. Electroless plating preparation and electromagnetic properties of Co-coated carbonyl iron particles/polyimide composite (United States)

    Zhou, Yingying; Zhou, Wancheng; Li, Rong; Qing, Yuchang; Luo, Fa; Zhu, Dongmei


    To solve the serious electromagnetic interference problems at elevated temperature, one thin microwave-absorbing sheet employing Co-coated carbonyl iron particles and polyimide was prepared. The Co-coated carbonyl iron particles were successfully prepared using an electroless plating method. The microstructure, composition, phase and static magnetic properties of Co-coated carbonyl iron particles were characterized by combination of scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The electromagnetic parameters of Co-coated carbonyl iron particles/polyimide composite were measured in the frequency range of 2-18 GHz, and the electromagnetic loss mechanism of the material-obtained was discussed. The microwave absorption properties of composites before and after heat treatment at 300 °C for 100 h were characterized in 2-18 GHz frequency range. It was established that composites based on Co-coated carbonyl iron demonstrate thermomagnetic stability, indicating that Co coating reduces the oxidation of carbonyl iron. Thus, Co-coated carbonyl iron particles/polyimide composites are useful in the design of microwave absorbers operating at temperatures up to 300 °C.

  10. Formation of Carbonyl and Carboxyl Groups on Cellulosic Pulps: Effect on Alkali Resistance

    Directory of Open Access Journals (Sweden)

    Jordan Perrin


    Full Text Available Ozone bleaching generates carbonyl groups on the cellulose polymer when applied to unbleached kraft pulps. This suggests that pulp fully bleached with a totally chlorine-free (TCF sequence may contain more oxidized groups than standard elemental chlorine-free (ECF bleached pulp. A fully bleached pulp was treated with sodium hypochlorite to form oxidized groups (mostly carbonyls on the pure carbohydrates, which were investigated during subsequent alkaline treatment. Carbonyl groups had a strong impact on color development during alkaline treatment. Among the carbonyls, the keto groups were the most active. This was confirmed by the behavior of carbohydrate model compounds that contained aldehyde, keto, and/or carboxyl groups when subjected to alkaline conditions. A subsequent hydrogen peroxide (P stage effectively decreased the carbonyl content, which reduced yellowing during alkaline treatment. However, the oxidized cellulose was severely depolymerized. The addition of magnesium sulfate (Mg into the P stage minimized depolymerization while maintaining some of the carbonyls in the carbohydrates. It is proposed that Mg cations can hinder alkaline β-elimination, possibly by forming a complex with the carbonyl groups.

  11. Paraquat exposure and Sod2 knockdown have dissimilar impacts on the Drosophila melanogaster carbonylated protein proteome. (United States)

    Narayanasamy, Suresh K; Simpson, David C; Martin, Ian; Grotewiel, Mike; Gronert, Scott


    Exposure to Paraquat and RNA interference knockdown of mitochondrial superoxide dismutase (Sod2) are known to result in significant lifespan reduction, locomotor dysfunction, and mitochondrial degeneration in Drosophila melanogaster. Both perturbations increase the flux of the progenitor ROS, superoxide, but the molecular underpinnings of the resulting phenotypes are poorly understood. Improved understanding of such processes could lead to advances in the treatment of numerous age-related disorders. Superoxide toxicity can act through protein carbonylation. Analysis of carbonylated proteins is attractive since carbonyl groups are not present in the 20 canonical amino acids and are amenable to labeling and enrichment strategies. Here, carbonylated proteins were labeled with biotin hydrazide and enriched on streptavidin beads. On-bead digestion was used to release carbonylated protein peptides, with relative abundance ratios versus controls obtained using the iTRAQ MS-based proteomics approach. Western blotting and biotin quantitation assay approaches were also investigated. By both Western blotting and proteomics, Paraquat exposure, but not Sod2 knockdown, resulted in increased carbonylated protein relative abundance. For Paraquat exposure versus control, the median carbonylated protein relative abundance ratio (1.53) determined using MS-based proteomics was in good agreement with that obtained using a commercial biotin quantitation kit (1.36).

  12. Variation of ambient carbonyl levels in urban Beijing between 2005 and 2012 (United States)

    Chen, Wentai; Shao, Min; Wang, Ming; Lu, Sihua; Liu, Ying; Yuan, Bin; Yang, Yudong; Zeng, Limin; Chen, Zhongming; Chang, Chih-Chung; Zhang, Qian; Hu, Min


    Carbonyl compounds are important precursors of secondary air pollutants. With the rapid economic development and the implementation of stricter control measures in Beijing, the sources of carbonyls possibly changed. Based on measurement data obtained at an urban site in Beijing between 2005 and 2012, we investigated annual variations in carbonyl levels and sources during these years. In summer, formaldehyde and acetaldehyde levels decreased significantly at a rate of 9.1%/year and 7.2%/year, respectively, while acetone levels increased at a rate of 4.3%/year. In winter, formaldehyde levels increased and acetaldehyde levels decreased. We also investigated the factors driving the variation in carbonyls levels during summer by determination of emission ratios for carbonyls and their precursors, and calculation of photochemical formation of carbonyls. The relative declines for primary formaldehyde and acetaldehyde levels were larger than those for secondary formation. This is possibly due to the increasing usage of natural gas and liquefied petroleum gas which could result in the rise of carbonyl precursor emission ratios. The increase in acetone levels might be related to the rising solvent usage in Beijing during these years. The influences of these sources should be paid more attention in future research.

  13. Allyl group as a protecting group for internucleotide phosphate and thiophosphate linkages in oligonucleotide synthesis: facile oxidation and deprotection conditions. (United States)

    Manoharan, M; Lu, Y; Casper, M D; Just, G


    [reaction: see text] The allyl group, which serves as a protecting group for an internucleotide bond for both phosphates and phosphorothioates, can be easily removed by good nucleophiles under weakly basic or neutral conditions. For a practical synthesis on solid support, camphorsulfonyloxaziridine was used as the oxidizing agent for synthesizing DNA, while the Beaucage reagent was used for preparing phosphorothioate oligomers. Both types of oligonucleotides were easily deprotected by concentrated ammonium hydroxide containing 2% mercaptoethanol.

  14. Platinum-catalyzed direct amination of allylic alcohols under mild conditions: ligand and microwave effects, substrate scope, and mechanistic study. (United States)

    Ohshima, Takashi; Miyamoto, Yoshiki; Ipposhi, Junji; Nakahara, Yasuhito; Utsunomiya, Masaru; Mashima, Kazushi


    Transition metal-catalyzed amination of allylic compounds via a pi-allylmetal intermediate is a powerful and useful method for synthesizing allylamines. Direct catalytic substitution of allylic alcohols, which forms water as the sole coproduct, has recently attracted attention for its environmental and economical advantages. Here, we describe the development of a versatile direct catalytic amination of both aryl- and alkyl-substituted allylic alcohols with various amines using Pt-Xantphos and Pt-DPEphos catalyst systems, which allows for the selective synthesis of various monoallylamines, such as the biologically active compounds Naftifine and Flunarizine, in good to high yield without need for an activator. The choice of the ligand was crucial toward achieving high catalytic activity, and we demonstrated that not only the large bite-angle but also the linker oxygen atom of the Xantphos and DPEphos ligands was highly important. In addition, microwave heating dramatically affected the catalyst activity and considerably decreased the reaction time compared with conventional heating. Furthermore, several mechanistic investigations, including (1)H and (31)P{(1)H} NMR studies; isolation and characterization of several catalytic intermediates, Pt(xantphos)Cl(2), Pt(eta(2)-C(3)H(5)OH)(xantphos), etc; confirmation of the structure of [Pt(eta(3)-allyl)(xantphos)]OTf by X-ray crystallographic analysis; and crossover experiments, suggested that formation of the pi-allylplatinum complex through the elimination of water is an irreversible rate-determining step and that the other processes in the catalytic cycle are reversible, even at room temperature.

  15. Synchrotron Photoionization Mass Spectrometry Measurements of Kinetics and Product Formation in the Allyl Radical (H2CCHCH2)Self Reaction (United States)

    Selby, Talitha M.; Melini, giovanni; Goulay, Fabien; Leone, Stephen R.; Fahr, Askar; Taatjes, Craig A.; Osborn, David L.


    Product channels for the self-reaction of the resonance-stabilized allyl radical, C3H5 + C3H5, have been studied with isomeric specificity at temperatures from 300-600 K and pressures from 1-6 Torr using time-resolved multiplexed photoionization mass spectrometry. Under these conditions 1,5-hexadiene was the only C6H10 product isomer detected. The lack of isomerization of the C6H10 product is in marked contrast to the C6H6 product in the related C3H3 + C3H3 reaction, and is due to the more saturated electronic structure of the C6H10 system. The disproportionation product channel, yielding allene + propene, was also detected, with an upper limit on the branching fraction relative to recombination of 0.03. Analysis of the allyl radical decay at 298 K yielded a total rate coefficient of (2.7 +/- 0.8) x 10(exp -11) cu cm/molecule/s, in good agreement with pre.vious experimental measurements using ultraviolet kinetic absorption spectroscopy and a recent theoretical determination using variable reaction coordinate transition state theory. This result provides independent indirect support for the literature value of the allyl radical ultraviolet absorption cross-section near 223 nm.

  16. FeCl3 -Catalyzed Ring-Closing Carbonyl-Olefin Metathesis. (United States)

    Ma, Lina; Li, Wenjuan; Xi, Hui; Bai, Xiaohui; Ma, Enlu; Yan, Xiaoyu; Li, Zhiping


    Exploiting catalytic carbonyl-olefin metathesis is an ongoing challenge in organic synthesis. Reported herein is an FeCl3 -catalyzed ring-closing carbonyl-olefin metathesis. The protocol allows access to a range of carbo-/heterocyclic alkenes with good efficiency and excellent trans diastereoselectivity. The methodology presents one of the rare examples of catalytic ring-closing carbonyl-olefin metathesis. This process is proposed to take place by FeCl3 -catalyzed oxetane formation followed by retro-ring-opening to deliver metathesis products.

  17. Visible Light-Induced Carbonylation Reactions with Organic Dyes as the Photosensitizers. (United States)

    Peng, Jin-Bao; Qi, Xinxin; Wu, Xiao-Feng


    Dyes can CO do it: Organic dyes and pigments are usually applied in textile dyeing, which can be dated back to the Neolithic period. Interestingly, the possibility to use organic dyes as photoredox catalysts has also been noticed by organic chemists and applied in organic synthesis. Carbonylation reactions as a powerful procedure in carbonyl-containing compound preparation have also been studied. In this manuscript, the recent achievements in using organic dyes as visible-light sensitizers in carbonylation chemistry are summarized and discussed.

  18. Rovibrational Spectroscopy of Aluminum Carbonyl Clusters in Helium Nanodroplets (United States)

    Liang, T.; Morrison, A. M.; Flynn, S. D.; Douberly, G. E.


    Helium nanodroplet isolation and a tunable quantum cascade laser are used to probe the fundamental CO stretch bands of Aluminum Carbonyl complexes, Al-(CO)N (n ≤ 5). The droplets are doped with single aluminum atoms via the resistive heating of an aluminum wetted tantalum wire. The downstream sequential pick-up of CO molecules leads to the rapid formation and cooling of Al-(CO)N clusters within the droplets. Near 1900 Cm-1, rotational fine structure is resolved in bands that are assigned to the CO stretch of a 2Π1/2 linear Al-CO species, and the asymmetric and symmetric CO stretch vibrations of a planar C2v Al-(CO)2 complex in a 2B1 electronic state. Bands corresponding to clusters with n ≥ 3 lack resolved rotational fine structure; nevertheless, the small frequency shifts from the n=2 bands indicate that these clusters consist of an Al-(CO)2 core with additional CO molecules attached via van-der-Waals interactions. A second n=2 band is observed near the CO stretch of Al-CO, indicating a local minimum on the n=2 potential consisting of an ``unreacted" Al-CO-(CO) cluster. The linewidth of this band is ˜0.5 cm-1, which is over 50 times broader than transitions within the Al-CO band. The additional broadening is consistent with a homogeneous mechanism corresponding to a rapid vibrational excitation induced reaction within the Al-CO-(CO) cluster to form the covalently bonded Al-(CO)2 complex. For the n=1,2 complexes, CCSD(T) calculations and Natural Bond Orbital (NBO) analyses are carried out to investigate the nature of the bonding in these complexes. The NBO calculations show that both π ``back" donation (from the occupied aluminum p-orbital into the π antibonding CO orbital) and σ donation (from CO into the empty aluminum p-orbitals) play a significant role in the bonding, analogous to transition metal carbonyl complexes. The large redshift of the CO stretch vibrations is consistent with this bonding analysis.

  19. Click synthesis of neutral, cationic, and zwitterionic poly(propargyl glycolide)-co-poly(ɛ-caprolactone)-based aliphatic polyesters as antifouling biomaterials. (United States)

    Tu, Qin; Wang, Jian-Chun; Liu, Rui; Chen, Yun; Zhang, Yanrong; Wang, Dong-En; Yuan, Mao-Sen; Xu, Juan; Wang, Jinyi


    With the development of polymer-based biomaterials, aliphatic polyesters have attracted considerable interest because of their non-toxicity, non-allergenic property, and good biocompatibility. However, the hydrophobic nature and the lack of side chain functionalities of aliphatic polyesters limit their biomedical applications. In this study, we prepared four new polyesters: poly(sulfobetaine methacrylate)-, poly(2-methacryloyloxyethyl phosphotidylcholine)-, poly(ethylene glycol)-, and quaternized poly[(2-dimethylamino)ethyl methacrylate]-grafted poly(propargyl glycolide)-co-poly(ɛ-caprolactone). Their synthesis was conducted through ring-opening polymerization of acetylene-functionalized lactones and subsequent graft of bioactive units using click chemistry. The chemical structures of the polyesters were characterized through nuclear magnetic resonance and Fourier-transform infrared spectroscopy, and their physical properties (including molecular weight, glass transition temperature, and melting point) were determined using gel permeation chromatography and differential scanning calorimetry. For studies on their hydrophilicity, stability, and anti-bioadhesive property, a series of polymeric surfaces of these polyesters was prepared by coating them onto glass substrates. The hydrophilicity and stability of these polyester surfaces were examined by contact angle measurements and attenuated total reflection Fourier-transform infrared spectroscopy. Their anti-bioadhesive property was investigated through protein adsorption, as well as cellular and bacterial adhesion assays. The prepared polyesters showed good hydrophilicity and long-lasting stability, as well as significant anti-fouling property. The newly prepared polyesters could be developed as promising anti-fouling materials with extensive biomedical applications.

  20. Photocatalytic Degradation of Trifluralin, Clodinafop-Propargyl, and 1,2-Dichloro-4-Nitrobenzene As Determined by Gas Chromatography Coupled with Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Niyaz A. Mir


    Full Text Available Phototransformation is considered one of the most key factors affecting the fate of pesticides. Therefore, our study focused on photocatalytic degradation of three selected pesticide derivatives: trifluralin (1, clodinafop-propargyl (2, and 1,2-dichloro-4-nitrobenzene (3. The degradation was carried out in acetonitrile/water medium in the presence of titanium dioxide (TiO2 under continuous purging of atmospheric air. The course of degradation was followed by thin-layer chromatography and gas chromatography-mass spectrometry techniques. Electron ionization mass spectrometry was used to identify the degradation species. GC-MS analysis indicates the formation of several intermediate products which have been characterized on the basis of molecular ion, mass fragmentation pattern, and comparison with NIST library. The photocatalytic degradation of pesticides of different chemical structures manifested distinctly different degradation mechanism. The major routes for the degradation of pesticides were found to be (a dealkylation, dehalogenation, and decarboxylation, (b hydroxylation, (c oxidation of side chain, if present, (d isomerization and cyclization, (e cleavage of alkoxy bond, and (f reduction of triple bond to double bond and nitro group to amino.

  1. S-Propargyl-cysteine Exerts a Novel Protective Effect on Methionine and Choline Deficient Diet-Induced Fatty Liver via Akt/Nrf2/HO-1 Pathway

    Directory of Open Access Journals (Sweden)

    Wenwen Li


    Full Text Available This study investigated the antioxidative effect of S-propargyl-cysteine (SPRC on nonalcoholic fatty liver (NAFLD by treating mice fed a methionine and choline deficient (MCD diet with SPRC for four weeks. We found that SPRC significantly reduced hepatic reactive oxygen species (ROS and methane dicarboxylic aldehyde (MDA levels. Moreover, SPRC also increased the superoxide dismutase (SOD activity. By Western blot, we found that this protective effect of SPRC was importantly attributed to the regulated hepatic antioxidant-related proteins, including protein kinase B (Akt, heme oxygenase-1 (HO-1, nuclear factor erythroid 2-related factor 2 (Nrf2, and cystathionine γ-lyase (CSE, an enzyme that synthesizes hydrogen sulfide. Next, we examined the detailed molecular mechanism of the SPRC protective effect using oleic acid- (OA- induced HepG2 cells. The results showed that SPRC significantly decreased intracellular ROS and MDA levels in OA-induced HepG2 cells by upregulating the phosphorylation of Akt, the expression of HO-1 and CSE, and the translocation of Nrf2. SPRC-induced HO-1 expression and Nrf2 translocation were abolished by the phosphoinositide 3-kinase (PI3K inhibitor LY294002. Moreover, the antioxidative effect of SPRC was abolished by CSE inhibitor DL-propargylglycine (PAG and HO-1 siRNA. Therefore, these results proved that SPRC produced an antioxidative effect on NAFLD through the PI3K/Akt/Nrf2/HO-1 signaling pathway.

  2. S-Propargyl-Cysteine, a Novel Hydrogen Sulfide Donor, Inhibits Inflammatory Hepcidin and Relieves Anemia of Inflammation by Inhibiting IL-6/STAT3 Pathway (United States)

    Xin, Hong; Zhu, Yi Zhun


    Anemia of inflammation (AI) is clinically prevalent and greatly threatens public health. Traditional remedies have raised controversy during clinical practice, calling for alternative therapies. We have recently found that hydrogen sulfide (H2S) inhibits inflammatory hepcidin, the critical mediator of AI. However, due to the chemical property of H2S, there remains an urgent need for a stable H2S donor in AI treatment. Here we reported that S-propargyl-cysteine (SPRC), a novel water-soluble H2S donor, suppressed hepatic hepcidin and corrected hypoferremia induced by lipopolysaccharide. The effects of SPRC were reversed by inhibition of cystathionine γ-lyase, one of the major endogenous H2S synthases. Moreover, SPRC reduced serum hepcidin, improved transferrin saturation, and maintained erythrocyte membrane integrity in a chronic mouse AI model. Consistently, splenomegaly was ameliorated and splenic iron accumulation relieved. Mechanism study indicated that serum IL-6 content and hepatic Il-6 mRNA were decreased by SPRC, in parallel with reduced hepatic JAK2/STAT3 activation. On the whole, our data reveal the inhibition of inflammatory hepcidin by SPRC, and suggest SPRC as a potential remedy against AI. PMID:27649298

  3. Detection of O-propargyl-puromycin with SUMO and ubiquitin by click chemistry at PML-nuclear bodies during abortive proteasome activities. (United States)

    Uozumi, Naoki; Matsumoto, Hotaru; Saitoh, Hisato


    The amino-nucleoside antibiotic, puromycin, acts by covalently linking to elongating polypeptide chains on ribosomes to generate prematurely terminated immature polypeptides. The trafficking of puromycin-conjugated (puromycylated) immature polypeptides within cell has, however, remained elusive. In this study, using O-propargyl-puromycin (OP-Puro), the distribution of puromycylated polypeptides was assessed in HeLa cells by click chemistry. Under standard culture conditions, OP-Puro signals were detected in the cytoplasm and nucleus with the highest concentrations in the nucleolus. Intriguingly, when proteasome activities were aborted using MG132, OP-Puro signals began to accumulate at promyelocytic leukemia nuclear bodies (PML-NBs) in addition to the nucleolus. We also found promiscuous association of OP-Puro signals with SUMO-2/3 and ubiquitin at PML-NBs, but not at the nucleolus, during abortive proteasome activities. This study reveals a previously unknown distribution of OP-Puro that argues for a nuclear function in regulating immature protein homeostasis.

  4. Cyclodiphosphazanes as synthetic probes: P-C/P-N bond formation from the reaction with functionalized propargyl alcohols and -hydroxy substrates

    Indian Academy of Sciences (India)

    G Gangadhararao; K C Kumara Swamy


    Phosphano-indoles were synthesized in a fairly straightforward route from the reaction of simple cyclodiphosphazanes [XP(-N-t-Bu)2PY] [X=Y=NH--Bu (1a); X=Y=NH-i-Pr (1b)] with o-aminophenyl functionalized propargyl alcohols. The reaction occurs via an allene intermediate formed by PIII-O-C→PV(O)-C rearrangement, followed by cyclization utilizing the central allenic carbon and the –NH2 functionality. In a similar way, cyclodiphosphazanes [XP(-N-t-Bu)2PY] [X=Y=Cl (1c); X=Cl, Y=NH--Bu(1d)] have been treated with N-hydroxy substrates to obtain novel PIII-O-N→PV(O)-N rearranged products.X-ray structures of the four products, 2-(1-phenyl-ethyl)-3-[(t-Bu)NH)P(-N--Bu)2P(O)]-indole [14], cis-{[-C(=O)-C6H4-C(=O)-]-N-P(=O)-N-t-Bu}2[cis-18], trans-{[-C(=O)-C6H4-C(=O)-]-N-P(=O)-N--Bu}2 [trans-18] and cis-[(-BuNH)P(-N-t−Bu)2P(=O)-N{-C(=O)-CH2-CH2-C(=O)-}] [cis-19] are also reported

  5. 烯丙基酚醛树脂的固化动力学%Curing Kinetics of Allyl Phenolic Resin

    Institute of Scientific and Technical Information of China (English)

    刘洋; 刘诗薇; 李志强; 于景坤


    The curing behavior of allyl phenolic resin was analyzed at different heating rates using differential scanning calorimetry.The obtained kinetic data were treated by Kissinger and KAS(Kissinger-Akahira-Sunose) methods to obtain the curing reaction kinetic parameters.A curing kinetics model was established for allyl phenolic resin.Compared with phenolic resin,the curing temperature of allyl phenolic resin is higher,the reaction order is closer to 1,and the average activation energy of the curing reaction is lower,111.45 kJ/mol.The activation energy of allyl phenolic resin is almost constant and changes little with temperature in the curing process.The curing kinetics model of allyl phenolic resin provides a theoretical basis for the study of curing process parameters.%利用差示扫描量热法分析了烯丙基酚醛树脂在不同升温速率下的固化行为,用Kissinger法和KAS(Kissinger-Akahira-Sunose)法对获得的动力学数据进行处理,得到了固化反应动力学参数,并建立了烯丙基酚醛树脂的固化动力学模型.结果表明:与纯酚醛树脂相比,烯丙基酚醛树脂固化温度较高,反应级数更接近于1,固化反应所需的平均表观活化能较低,为111.45kJ/mol;在整个固化过程中,烯丙基酚醛树脂的活化能较为恒定,随温度变化不大;烯丙基酚醛树脂固化动力学模型为研究该体系固化工艺参数提供了理论依据.

  6. Mechanism of heterogeneous reaction of carbonyl sulfide on magnesium oxide. (United States)

    Liu, Yongchun; He, Hong; Xu, Wenqing; Yu, Yunbo


    Heterogeneous reaction of carbonyl sulfide (OCS) on magnesium oxide (MgO) under ambient conditions was investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), quadrupole mass spectrometer (QMS), and density functional theory (DFT) calculations. It reveals that OCS can be catalytically hydrolyzed by surface hydroxyl on MgO to produce carbon dioxide (CO2) and hydrogen sulfide (H2S), and then H2S can be further catalytically oxidized by surface oxygen or gaseous oxygen on MgO to form sulfite (SO3(2-)) and sulfate (SO4(2-)). Hydrogen thiocarbonate (HSCO2-) was found to be the crucial intermediate. Surface hydrogen sulfide (HS), sulfur dioxide (SO2), and surface sulfite (SO3(2-)) were also found to be intermediates for the formation of sulfate. Furthermore, the surface hydroxyl contributes not only to the formation of HSCO2- but also to HSCO2- decomposition. On the basis of experimental results, the heterogeneous reaction mechanism of OCS on MgO was discussed.

  7. Thermal characterization of magnetically aligned carbonyl iron/agar composites. (United States)

    Diaz-Bleis, D; Vales-Pinzón, C; Freile-Pelegrín, Y; Alvarado-Gil, J J


    Composites of magnetic particles into polymeric matrices have received increasing research interest due to their capacity to respond to external magnetic or electromagnetic fields. In this study, agar from Gelidium robustum has been chosen as natural biocompatible polymer to build the matrix of the magnetic carbonyl iron particles (CIP) for their uses in biomedical fields. Heat transfer behavior of the CIP-agar composites containing different concentrations (5, 10, 15, 20, 25 and 30% w/w) of magnetically aligned and non-aligned CIP in the agar matrix was studied using photothermal radiometry (PTR) in the back-propagation emission configuration. The morphology of the CIP-agar composites with aligned and non-aligned CIP under magnetic field was also evaluated by scanning electron microscopy (SEM). The results revealed a dominant effect of CIP concentration over the alignment patterns induced by the magnetic field, which agrees with the behavior of the thermal diffusivity and thermal conductivity. Agar served as a perfect matrix to be used with CIP, and CIP-agar composites magnetically aligned at 20% CIP concentration can be considered as promising 'smart' material for hyperthermia treatments in the biomedical field.

  8. Photodecomposition of Molybdenum andTungsten Carbonyl Complexes

    Directory of Open Access Journals (Sweden)

    Thamer A. Alwani


    Full Text Available The photodecomposition of four different colored organometallic molybdenum and tungsten carbonyl complexes, i.e. [Mo(CO52LA] (complex I, [(Mo(CO3(bipy2LB] (complex II, [(W(CO3(tmen2LB] (complex III and [Mo(CO2LC]2 (complex I V where LA 2-phenyl-1,3-indandionebis(2-methyl anilines, LB 2-phenyl-1,3-indandione bis (4-hydroxy anilines and LCbis (2-hydroxo-benzalydine benzidine ion have been performed at 365 nm in chloroform at 25 °C under oxygen atmosphere. The absorbance spectrum of these complexes has been recorded with the time of irradiation in order to examine the kinetics of photodecomposition. The rate of the photodecomposition process was investigated and the relative values of the rate constants of dissociation (Kd for the first-order reaction are tabulated. The apparent rate constant of photodecomposition was found to be (8.33-11.50 × 10-5 s-1.

  9. Tropical sources and sinks of carbonyl sulfide observed from space (United States)

    Glatthor, Norbert; Höpfner, Michael; Baker, Ian T.; Berry, Joe; Campbell, Elliott; Kawa, Stephan R.; Krysztofiak, Gisele; Sinnhuber, Björn-Martin; Stiller, Gabriele; Stinecipher, Jim; von Clarmann, Thomas


    According to current budget estimations the seasonal variation of carbonyl sulfide (COS) is governed by oceanic release and vegetation uptake. Its assimilation by plants is assumed to be similar to the photosynthetic uptake of CO2 but, contrary to the latter process, to be irreversible. Therefore COS has been suggested as co-tracer of the carbon cycle. Observations of COS, however, are sparse, especially in tropical regions. We use the comprehensive data set of spaceborne measurements of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) to analyze its global distribution. Two major features are observed in the tropical upper troposphere around 250 hPa: enhanced amounts over the western Pacific and the Maritime Continent, peaking around 550 pptv in boreal summer, and a seasonally varying depletion of COS extending from tropical South America to Africa. The large-scale COS depletion, which in austral summer amounts up to -40 pptv as compared to the rest of the respective latitude band, has not been observed before and reveals the seasonality of COS uptake through tropical vegetation. The observations can only be reproduced by global models, when a large vegetation uptake and a corresponding increase in oceanic emissions as proposed in several recent publications is assumed.

  10. The oceanic cycle and global atmospheric budget of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, P.S.


    A significant portion of stratospheric air chemistry is influenced by the existence of carbonyl sulfide (COS). This ubiquitous sulfur gas represents a major source of sulfur to the stratosphere where it is converted to sulfuric acid aerosol particles. Stratospheric aerosols are climatically important because they scatter incoming solar radiation back to space and are able to increase the catalytic destruction of ozone through gas phase reactions on particle surfaces. COS is primarily formed at the surface of the earth, in both marine and terrestrial environments, and is strongly linked to natural biological processes. However, many gaps in the understanding of the global COS cycle still exist, which has led to a global atmospheric budget that is out of balance by a factor of two or more, and a lack of understanding of how human activity has affected the cycling of this gas. The goal of this study was to focus on COS in the marine environment by investigating production/destruction mechanisms and recalculating the ocean-atmosphere flux.

  11. Carbonyl Sulfide for Tracing Carbon Fluxes Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J. Elliott [Univ. of California, Merced, CA (United States); Berry, Joseph A. [Carnegie Inst. of Science, Stanford, CA (United States); Billesbach, Dave [Univ. of Nebraska, Lincoln, NE (United States); Torn, Margaret S [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zahniser, Mark [Aerodyne Research, Inc., Billerica, MA (United States); Seibt, Ulrike [Univ. of California, Los Angeles, CA (United States); Maseyk, Kadmiel [Pierre and Marie Curie Univ., Paris (France)


    The April-June 2012 campaign was located at the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains (SGP) site Central Facility and had three purposes. One goal was to demonstrate the ability of current instrumentation to correctly measure fluxes of atmospheric carbonyl sulfide (COS). The approach has been describe previously as a critical approach to advancing carbon cycle science1,2, but requires further investigation at the canopy scale to resolve ecosystem processes. Previous canopy-scale efforts were limited to data rates of 1Hz. While 1 Hz measurements may work in a few ecosystems, it is widely accepted that data rates of 10 to 20 Hz are needed to fully capture the exchange of traces gases between the atmosphere and vegetative canopy. A second goal of this campaign was to determine if canopy observations could provide information to help interpret the seasonal double peak in airborne observations at SGP of CO2 and COS mixing ratios. A third goal was to detect potential sources and sinks of COS that must be resolved before using COS as a tracer of gross primary productivity (GPP).

  12. Regional-Scale Carbon Flux Partitioning Using Atmospheric Carbonyl Sulfide (United States)

    Abu-Naser, M.; Campbell, J. E.; Berry, J. A.


    Simultaneous analysis of atmospheric concentrations of carbonyl sulfide (COS) and carbon dioxide (CO2) has been proposed as an approach to partitioning gross primary production and respiration fluxes at regional and global scales. The basis for this approach was that the observation and regional gradients in atmospheric CO2 are dominated by net ecosystem fluxes while regional gradients in atmospheric COS are dominated by GPP-related plant uptake. Here we investigate the spatial and temporal gradients in airborne COS and CO2 measurements in comparison to flux estimates from ecosystem models and eddy covariance methods over North America. The spatial gradients in the ecosystem relative uptake (ERU), the normalized ratio of COS and CO2 vertical gradients, were consistent with the theoretical relationship to flux estimates from ecosystem models and eddy covariance methods. The seasonality of the gross primary productivity flux estimates was consistent with airborne observations in the midwestern region but had mixed results in the southeastern region. Inter-annual changes in the ERU and regional drought index data suggested a potential relationship between drought stress and low ratios of gross primary production to net ecosystem exchange.

  13. Heterogeneous oxidation of carbonyl sulfide on mineral oxides

    Institute of Scientific and Technical Information of China (English)

    LIU YongChun; LIU JunFeng; HE Hong; YU YunBo; XUE Li


    Heterogeneous oxidation of carbonyl sulfide (OCS) on mineral oxides including SiO2, Fe2O3, CaO, MgO, ZnO and TiO2, which are the main components of atmospheric particles, were investigated using in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS), ion chromatography (IC), temperature-programmed desorption (TPD), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) methods. The main products and intermediates of the heterogeneous oxidation of OCS on these oxides were identified with in situ DRIFTS and IC. The reaction mechanism and kinetics were also discussed. It is found that the reaction mechanism on these mineral oxides is the same as that on Al2O3 for the same final products and the intermediates at room temperature. Namely, OCS can be catalytically oxidized to produce surface SO42- species and gaseous CO2 through the surface hydrogen thiocarbonate (HSCO2-) and HSO3- species. The activity series for heterogeneous oxidation of OCS follows: Al2O3 ≈ CaO>MgO>TiO2 ≈ ZnO>Fe2O3>SiO2. The specific area, basic hydroxyl and surface basicity of these oxides have effect on the reactivity. This study suggests that heterogeneous reactions of OCS on mineral dust may be an unneglectable sink of OCS.

  14. Teratogenicity and embryotoxicity of nickel carbonyl in Syrian hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Sunderman, F.W. Jr.; Shen, S.K.; Reid, M.C.; Allpass, P.R.


    Nickel carbonyl was administered to groups of pregnant hamsters by inhalation on days 4, 5, 6, 7, or 8 of gestation. The dams were killed on day 15 of gestation, and the fetuses were examined for malformations. Exposure to Ni(CO)/sub 4/ on days 4 or 5 of gestation resulted in malformation in 5.5% and 5.8% of the progeny, respectively. Progeny included 9 fetuses with cystic lungs, 7 fetuses with exencephaly, 1 fetus with exencephaly plus fused rib and 1 fetus with anophthalmia plus cleft palate. Hemorrhages into serious cavities were found. In progeny of dams exposed to Ni(CO)/sub 4/ on days 6 or 7 of gestation, there was 1 fetus with fused ribs and there were 2 fetuses with hydronephrosis. In another experiment, pregnant hamsters were exposed to inhalation of Ni(CO)/sub 4/ on day 5 of gestation; these dams were permitted to deliver their litters and to nurse their pups. There was no significant difference in the average number of live pups in the Ni(CO)/sub 4/-exposed litters compared to control litters. Neonatal mortality was increased in Ni(CO)/sub 4/-exposed litters. This study demonstrates that Ni(CO)/sub 4/ is teratogenic and embryotoxic in Syrian hamsters.

  15. Carbonyl sulfide uptake and chloroform emissions from an Arctic site (United States)

    Elkins, J. W.; Dutton, G. S.; Montzka, S. A.; Nance, J. D.; Hall, B. D.; Thoning, K. W.; Miller, J. B.; White, J.; Vaugh, B.; Manning, A.


    The Arctic Region is most sensitive to future climate change. Quantifying emissions and sinks of many important biogenic trace gases there may become important indicators of potential climate feedback. Once snowmelt at Pt. Barrow, Alaska (77o N) occurs, ground cover is exposed by sunlight and higher temperatures, then photosynthesis starts up. Peaks of chloroform (CHCl3) appear throughout the summer from southerly-based air masses based over northern Alaska and northwest Canada. Carbonyl sulfide (COS) undergoes uptake throughout the summer season through the same enzymes that uptake carbon dioxide (CO2). We will calculate the footprint of emissions of CHCl3 and uptake of COS using high frequency in situ observations, and the NAME and FLEXPART models. Previous studies show a large source of CHCl3 (8% of the total budget) may be coming from soils in high latitude pine forests. We will examine emissions of CHCl3 to see whether or not they are coming from the tundra just south of Pt. Barrow. We will identify the regions for uptake of COS and CO2 from the footprint generated from the models.

  16. Degradation of ambient carbonyl sulfide by Mycobacterium spp. in soil. (United States)

    Kato, Hiromi; Saito, Masahiko; Nagahata, Yoshiko; Katayama, Yoko


    The ability to degrade carbonyl sulfide (COS) was confirmed in seven bacterial strains that were isolated from soil, without the addition of COS. Comparative 16S rRNA gene sequence analysis indicated that these isolates belonged to the genera Mycobacterium, Williamsia and Cupriavidus. For example, Mycobacterium sp. strain THI401, grown on PYG agar medium, was able to degrade an initial level of 30 parts per million by volume COS within 1 h, while 60 % of the initial COS was decreased by abiotic conversion in 30 h. Considering natural COS flux between soil and the atmosphere, COS degradation by these bacteria was confirmed at an ambient level of 500 parts per trillion by volume (p.p.t.v.), using sterilized soil to cultivate the bacterium. Autoclave sterilization of soil resulted in a small amount of COS emission, while Mycobacterium spp. degraded COS at a faster rate than it was emitted from the soil, and reduced the COS mixing ratio to a level that was lower than the ambient level: THI401 degraded COS from an initial level of 530 p.p.t.v. to a level of 330 p.p.t.v. in 30 h. These results provide experimental evidence of microbial activity in soil as a sink for atmospheric COS.

  17. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, Matthias, E-mail:; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander


    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO{sub 2} and reduced to graphite to determine {sup 14}C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  18. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry (United States)

    Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander


    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  19. Protective mechanisms of Cucumis sativus in diabetes-related models of oxidative stress and carbonyl stress

    Directory of Open Access Journals (Sweden)

    Himan Heidari


    Conclusion: It can be concluded that C. sativus has protective effects in diabetes complications and can be considered a safe and suitable candidate for decreasing the oxidative stress and carbonyl stress that is typically observed in diabetes mellitus.

  20. A carbonyl iron/carbon fiber material for electromagnetic wave absorption. (United States)

    Youh, Meng-Jey; Wu, Hung-Chih; Lin, Wang-Hua; Chiu, Sheng-Cheng; Huang, Chien-Fa; Yu, Hsin-Chih; Hsu, Jen-Sung; Li, Yuan-Yao


    A carbonyl iron/carbon fiber material consisting of carbon fibers grown on micrometer-sized carbonyl iron sphere, was synthesized by chemical vapor deposition using a mixture of C2H2 and H2. The hollow-core carbon fibers (outer diameter: 140 nm and inner diameter: 40 nm) were composed of well-ordered graphene layers which were almost parallel to the long axis of the fibers. A composite (2 mm thick) consisting of the carbonyl iron/carbon fibers and epoxy resin demonstrated excellent electromagnetic (EM) wave absorption. Minimum reflection losses of -36 dB (99.95% of EM wave absorption) at 7.6 GHz and -32 dB (99.92% of EM wave absorption) at 34.1 GHz were achieved. The well-dispersed and network-like carbon fibers in the resin matrix affected the dielectric loss of the EM wave while the carbonyl iron affected the magnetic loss.

  1. Corrosion inhibition of α,β-unsaturated carbonyl compounds on steel in acid medium

    Institute of Scientific and Technical Information of China (English)

    Gao Jiancun; Weng Yongji; Salitanate; Feng Li; Yue Hong


    Corrosion inhibition of three α,β-unsaturated carbonyl compounds on N80 steel at high temperature and in concentrated acid medium was evaluated, and the inhibition mechanism was investigated.The results proved that both cinnamaidehyde and benzalacetone had an evident anticorrosion effect and could reduce the corrosion of steel effectively in acid medium, α,β-unsaturated carbonyl compounds with a benzene ring structure had good adsorption on steel surface.The experiments proved that polymerization of α,β-unsaturated carbonyl compounds on the steel surface at a high temperature and in concentrated acid medium resulted in a good corrosion inhibiting effect, which was attributed to the structures of α,β-unsaturated carbonyl compounds.

  2. Efficient and selective α-bromination of carbonyl compounds with N-bromosuccinimide under microwave

    KAUST Repository

    Guan, Xiao-Yu


    A highly efficient method for the synthesis of α-halocarbonyl compounds has been achieved via selective monobromination of aromatic and aliphatic carbonyl compounds with N-bromosuccinimide catalyzed by p-toluenesulfonic acid under microwave irradiation within 30 min.

  3. Incorporating Cobalt Carbonyl Moieties onto Ethynylthiophene-Based Dithienylcyclopentene Switches. 1. Photochemistry

    NARCIS (Netherlands)

    Harvey, Emma C.; Areephong, Jetsuda; Cafolla, Attilio A.; Long, Conor; Browne, Wesley R.; Pryce, Mary T.; Feringa, Bernard


    The synthesis and characterization of a series of dithienyl perhydro- and perfluorocyclopentene photochromic molecular switches appended with cobalt carbonyl binding 3-ethynylthiophene and phenyl-3-ethynylthiophene substituents are reported. Their photochromic properties, fatigue resistance, and the

  4. On the antioxidant, neuroprotective and anti-inflammatory properties of S-allyl cysteine: An update. (United States)

    Colín-González, Ana Laura; Ali, Syed F; Túnez, Isaac; Santamaría, Abel


    Therapeutic approaches based on isolated compounds obtained from natural products to handle central and peripheral disorders involving oxidative stress and inflammation are more common nowadays. The validation of nutraceutics vs. pharmaceutics as tools to induce preventive and protective profiles in human health alterations is still far of complete acceptance, but the basis to start more solid experimental and clinical protocols with natural products has already begun. S-allyl cysteine (SAC) is a promising garlic-derived organosulfur compound exhibiting a considerable number of positive actions in cell models and living systems. An update, in the form of review, is needed from time to time to get access to the state-of-the-art on this topic. In this review we visited recent and refreshing evidence of new already proven and potential targets to explain the benefits of using SAC against toxic and pathological conditions. The broad spectrum of protective actions covered by this molecule comprises antioxidant, redox modulatory and anti-inflammatory activities, accompanied by anti-apoptotic, pro-energetic and signaling capacities. Herein, we detail the evidence on these aspects to provide the reader a more complete overview on the promising aspects of SAC in research.

  5. Merging allylic carbon-hydrogen and selective carbon-carbon bond activation (United States)

    Masarwa, Ahmad; Didier, Dorian; Zabrodski, Tamar; Schinkel, Marvin; Ackermann, Lutz; Marek, Ilan


    Since the nineteenth century, many synthetic organic chemists have focused on developing new strategies to regio-, diastereo- and enantioselectively build carbon-carbon and carbon-heteroatom bonds in a predictable and efficient manner. Ideal syntheses should use the least number of synthetic steps, with few or no functional group transformations and by-products, and maximum atom efficiency. One potentially attractive method for the synthesis of molecular skeletons that are difficult to prepare would be through the selective activation of C-H and C-C bonds, instead of the conventional construction of new C-C bonds. Here we present an approach that exploits the multifold reactivity of easily accessible substrates with a single organometallic species to furnish complex molecular scaffolds through the merging of otherwise difficult transformations: allylic C-H and selective C-C bond activations. The resulting bifunctional nucleophilic species, all of which have an all-carbon quaternary stereogenic centre, can then be selectively derivatized by the addition of two different electrophiles to obtain more complex molecular architecture from these easily available starting materials.

  6. Non-Directed Allylic C-H Acetoxylation in the Presence of Lewis Basic Heterocycles. (United States)

    Malik, Hasnain A; Taylor, Buck L H; Kerrigan, John R; Grob, Jonathan E; Houk, K N; Du Bois, J; Hamann, Lawrence G; Patterson, Andrew W


    We outline a strategy to enable non-directed Pd(II)-catalyzed C-H functionalization in the presence of Lewis basic heterocycles. In a high-throughput screen of two Pd-catalyzed C-H acetoxylation reactions, addition of a variety of N-containing heterocycles is found to cause low product conversion. A pyridine-containing test substrate is selected as representative of heterocyclic scaffolds that are hypothesized to cause catalyst arrest. We pursue two approaches in parallel that allow product conversion in this representative system: Lewis acids are found to be effective in situ blocking groups for the Lewis basic site, and a pre-formed pyridine N-oxide is shown to enable high yield of allylic C-H acetoxylation. Computational studies with density functional theory (M06) of binding affinities of selected heterocycles to Pd(OAc)2 provide an inverse correlation of the computed heterocycle-Pd(OAc)2 binding affinities with the experimental conversions to products. Additionally, (1)H NMR binding studies provide experimental support for theoretical calculations.

  7. Allyl functionalized phosphinite and phosphonite ligands: Synthesis, transition metal chemistry and orthopalladation reactions

    Indian Academy of Sciences (India)

    Singappagudem Govindaraju; Guddekoppa S Ananthnag; Susmita Naik; Shaikh M Mobin; Maravanji S Balakrishn


    Allyl functionalized phosphinite PPh2(OAr) [Ar=C6H4(-C3H5)] (1) and phosphonite PPh(OAr)2 (2) ligands were prepared by the reactions of 2-allylphenol with PPh2Cl and PPhCl2, respectively. The ruthenium(II) complexes, [Ru(6--cymene)(PPh2(OAr))Cl2] (3) and [Ru(6--cymene)(PPh(OAr)2Cl2)] (4) were obtained by reacting 1 or 2 with [Ru(6--cymene)Cl2]2 in 2:1 molar ratios, respectively. Reactions of 1 or 2 with AuCl(SMe2) gave [Au{PPh2(OAr)}Cl] (5) or [Au{PPh(OAr)2}Cl] (6) in good yield. The palladium complex, [Pd{PPh(OAr)2}2Cl2] (7) was prepared by reacting Pd(COD)Cl2 with 2 in 1:2 molar ratio. The reaction between Pd(COD)Cl2 and 1 yielded a mixture of orthopalladated cis- and trans-[Pd(Ph2P(OAr))Cl]2 (8a and 8b). The treatment of 8 with PPh3 and Ph2PCH2PPh2 resulted in the cleavage of chloro bridge to give respectively, [Ph2(OAr)PPd(PPh3)Cl] (9) and [Ph2(ArO)PPd(2-dppm)]OTf (10). Single crystal X-ray structure of the ruthenium complex 3 is described.

  8. Release and antibacterial activity of allyl isothiocyanate/β-cyclodextrin complex encapsulated in electrospun nanofibers. (United States)

    Aytac, Zeynep; Dogan, Sema Y; Tekinay, Turgay; Uyar, Tamer


    Allyl isothiocyanate (AITC) is known as an efficient antibacterial agent but it has a very high volatility. Herein, AITC and AITC/β-cyclodextrin (CD)-inclusion complex (IC) incorporated in polyvinyl alcohol (PVA) nanofibers were produced via electrospinning. SEM images elucidated that incorporation of AITC and AITC/β-CD-IC into polymer matrix did not affect the bead-free fiber morphology of PVA nanofibers. (1)H-NMR and headspace GC-MS analyses revealed that very low amount of AITC was remained in PVA/AITC-NF because of the rapid evaporation of AITC during the electrospinning process. Nevertheless, much higher amount of AITC was preserved in the PVA/AITC/β-CD-IC-NF due to the CD inclusion complexation. The sustained release of AITC from nanofibers was evaluated at 30°C, 50°C and 75°C via headspace GC-MS. When compared to PVA/AITC-NF, PVA/AITC/β-CD-IC-NF has shown higher antibacterial activity against Escherichia coli and Staphylococcus aureus due to the presence of higher amount of AITC in this sample which was preserved by CD-IC.

  9. Hydrolysis of cellulose catalyzed by quaternary ammonium perrhenates in 1-allyl-3-methylimidazolium chloride. (United States)

    Wang, Jingyun; Zhou, Mingdong; Yuan, Yuguo; Zhang, Quan; Fang, Xiangchen; Zang, Shuliang


    Quaternary ammonium perrhenates were applied as catalyst to promote the hydrolysis of cellulose in 1-allyl-3-methylimidazolium chloride ([Amim]Cl). The quaternary ammonium perrhenates displayed good catalytic performance for cellulose hydrolysis. Water was also proven to be effective to promote cellulose hydrolysis. Accordingly, 97% of total reduced sugar (TRS) and 42% of glucose yields could be obtained under the condition of using 5mol% of tetramethyl ammonium perrhenate as catalyst, 70μL of water, ca. 0.6mmol of microcrystalline cellulose (MCC) and 2.0g of [Amim]Cl as solvent under microwave irradiation for 30min at 150°C (optimal conditions). The influence of quaternary ammonium cation on the efficiency of cellulose hydrolysis was examined based on different cation structures of perrhenates. The mechanism on perrhenate catalyzed cellulose hydrolysis is also discussed, whereas hydrogen bonding between ReO4 anion and hydroxyl groups of cellulose is assumed to be the key step for depolymerization of cellulose.

  10. Synergistic effect of allyl isothiocyanate (AITC) on cisplatin efficacy in vitro and in vivo. (United States)

    Ling, Xiang; Westover, David; Cao, Felicia; Cao, Shousong; He, Xiang; Kim, Hak-Ryul; Zhang, Yuesheng; Chan, Daniel Cf; Li, Fengzhi


    Although in vitro studies have shown that isothiocyanates (ITCs) can synergistically sensitize cancer cells to cisplatin treatment, the underlying mechanisms have not been well defined, and there are no in vivo demonstrations of this synergy. Here, we report the in vitro and in vivo data for the combination of allyl isothiocyanate (AITC), one of the most common naturally occurring ITCs, with cisplatin. Our study revealed that cisplatin and AITC combination synergistically inhibits cancer cell growth and colony formation, and enhances apoptosis in association with the downregulation of antiapoptotic proteins Bcl-2 and survivin. Importantly, the in vivo combination treatment suppresses human tumor growth in animal models without observable increases in toxicity (body weight loss) in comparison with single agent treatment. Furthermore, our data revealed that addition of AITC to cisplatin treatment changes the profile of G2/M arrest (e.g. increase in M phase cell number) and significantly extends the duration of G2/M arrest in comparison with cisplatin treatment alone. To explore the underlying mechanism, we found that AITC treatment rapidly depletes b-tubulin. Combination of AITC and cisplatin inhibits the expression of G2/M checkpoint-relevant proteins including CDC2, cyclin B1 and CDC25. Together, our findings reveal a novel mechanism for AITC enhancing cisplatin efficacy and provides the first in vivo evidence to support ITCs as potential candidates for developing new regimens to overcome platinum resistance.

  11. Pharmacokinetics, Tissue Distribution, and Anti-Lipogenic/Adipogenic Effects of Allyl-Isothiocyanate Metabolites.

    Directory of Open Access Journals (Sweden)

    Yang-Ji Kim

    Full Text Available Allyl-isothiocyanate (AITC is an organosulfur phytochemical found in abundance in common cruciferous vegetables such as mustard, wasabi, and cabbage. Although AITC is metabolized primarily through the mercapturic acid pathway, its exact pharmacokinetics remains undefined and the biological function of AITC metabolites is still largely unknown. In this study, we evaluated the inhibitory effects of AITC metabolites on lipid accumulation in vitro and elucidated the pharmacokinetics and tissue distribution of AITC metabolites in rats. We found that AITC metabolites generally conjugate with glutathione (GSH or N-acetylcysteine (NAC and are distributed in most organs and tissues. Pharmacokinetic analysis showed a rapid uptake and complete metabolism of AITC following oral administration to rats. Although AITC has been reported to exhibit anti-tumor activity in bladder cancer, the potential bioactivity of its metabolites has not been explored. We found that GSH-AITC and NAC-AITC effectively inhibit adipogenic differentiation of 3T3-L1 preadipocytes and suppress expression of PPAR-γ, C/EBPα, and FAS, which are up-regulated during adipogenesis. GSH-AITC and NAC-AITC also suppressed oleic acid-induced lipid accumulation and lipogenesis in hepatocytes. Our findings suggest that AITC is almost completely metabolized in the liver and rapidly excreted in urine through the mercapturic acid pathway following administration in rats. AITC metabolites may exert anti-obesity effects through suppression of adipogenesis or lipogenesis.

  12. Allyl Isothiocyanate Inhibits Actin-Dependent Intracellular Transport in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Bjørnar Sporsheim


    Full Text Available Volatile allyl isothiocyanate (AITC derives from the biodegradation of the glucosinolate sinigrin and has been associated with growth inhibition in several plants, including the model plant Arabidopsis thaliana. However, the underlying cellular mechanisms of this feature remain scarcely investigated in plants. In this study, we present evidence of an AITC-induced inhibition of actin-dependent intracellular transport in A. thaliana. A transgenic line of A. thaliana expressing yellow fluorescent protein (YFP-tagged actin filaments was used to show attenuation of actin filament movement by AITC. This appeared gradually in a time- and dose-dependent manner and resulted in actin filaments appearing close to static. Further, we employed four transgenic lines with YFP-fusion proteins labeling the Golgi apparatus, endoplasmic reticulum (ER, vacuoles and peroxisomes to demonstrate an AITC-induced inhibition of actin-dependent intracellular transport of or, in these structures, consistent with the decline in actin filament movement. Furthermore, the morphologies of actin filaments, ER and vacuoles appeared aberrant following AITC-exposure. However, AITC-treated seedlings of all transgenic lines tested displayed morphologies and intracellular movements similar to that of the corresponding untreated and control-treated plants, following overnight incubation in an AITC-absent environment, indicating that AITC-induced decline in actin-related movements is a reversible process. These findings provide novel insights into the cellular events in plant cells following exposure to AITC, which may further expose clues to the physiological significance of the glucosinolate-myrosinase system.

  13. Allyl m-Trifluoromethyldiazirine Mephobarbital: An Unusually Potent Enantioselective and Photoreactive Barbiturate General Anesthetic

    Energy Technology Data Exchange (ETDEWEB)

    Savechenkov, Pavel Y.; Zhang, Xi; Chiara, David C.; Stewart, Deirdre S.; Ge, Rile; Zhou, Xiaojuan; Raines, Douglas E.; Cohen, Jonathan B.; Forman, Stuart A.; Miller, Keith W.; Bruzik, Karol S. (Harvard-Med); (Mass. Gen. Hosp.); (UIC)


    We synthesized 5-allyl-1-methyl-5-(m-trifluoromethyl-diazirynylphenyl)barbituric acid (14), a trifluoromethyldiazirine-containing derivative of general anesthetic mephobarbital, separated the racemic mixture into enantiomers by chiral chromatography, and determined the configuration of the (+)-enantiomer as S by X-ray crystallography. Additionally, we obtained the {sup 3}H-labeled ligand with high specific radioactivity. R-(-)-14 is an order of magnitude more potent than the most potent clinically used barbiturate, thiopental, and its general anesthetic EC{sub 50} approaches those for propofol and etomidate, whereas S-(+)-14 is 10-fold less potent. Furthermore, at concentrations close to its anesthetic potency, R-(-)-14 both potentiated GABA-induced currents and increased the affinity for the agonist muscimol in human {alpha}1{beta}2/3{gamma}2L GABA{sub A} receptors. Finally, R-(-)-14 was found to be an exceptionally efficient photolabeling reagent, incorporating into both {alpha}1 and {beta}3 subunits of human {alpha}1{beta}3 GABAA receptors. These results indicate R-(-)-14 is a functional general anesthetic that is well-suited for identifying barbiturate binding sites on Cys-loop receptors.

  14. Efficient alpha-Methylenation of Carbonyl Compounds in Ionic Liquids at Room Temperature


    Vale, JA; Zanchetta, DF; Moran, PJS; RODRIGUES, JAR


    The application of several 1-butyl-3-methylimidazolium (BMIM) salt ionic liquids as solvent in the alpha-methylenation of carbonyl compounds at room temperature is reported. The ionic liquid [BMIM][NTf(2)] gave a clean reaction in a short time and good yields of several alpha-methylene carbonyl compounds. This ionic liquid was reused without affecting the reaction rates or yields over seven runs.

  15. Measurement of airborne carbonyls using an automated sampling and analysis system. (United States)

    Aiello, Mauro; McLaren, Robert


    Based upon the well established method of derivitization with 2,4-dinitrophenylhydrazine, an instrument was developed for ambient measurement of carbonyls with significantly improved temporal resolution and detection limits through automation, direct injection, and continuous use of a single microsilica DNPH cartridge. Kinetic experiments indicate that the derivitization reaction on the cartridge is fast enough for continuous measurements with 50 min air sampling. Reaction efficiencies measured on the cartridge were 100% for the carbonyls tested, including formaldehyde, acetaldehyde, propanal, acetone, and benzaldehyde. Transmission of the carbonyls through an ozone scrubber (KI) were in the range of 97-101%. Blank levels and detection limits were lower than those obtainable with conventional DNPH methods by an order of magnitude or greater. Mixing ratio detection limits of carbonyls in ambient air were 38-73 ppt for a 50 min air sample (2.5 L). The instrument made continuous measurements of carbonyls on a 2 h cycle over a period of 10 days during a field study in southwestern Ontario. Median mixing ratios were 0.58 ppb formaldehyde; 0.29 ppb acetaldehyde; 1.14 ppb acetone; and 0.45 ppb glyoxal. Glyoxal shows a significant correlation with ozone and zero intercept, consistent with a secondary source and minor direct source to the atmosphere. The method should easily be extendable to the detection of other low molecular weight carbonyls that have been previously reported using the DNPH technique.

  16. Oxidative Stress and Carbonyl Lesions in Ulcerative Colitis and Associated Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Zhiqi Wang


    Full Text Available Oxidative stress has long been known as a pathogenic factor of ulcerative colitis (UC and colitis-associated colorectal cancer (CAC, but the effects of secondary carbonyl lesions receive less emphasis. In inflammatory conditions, reactive oxygen species (ROS, such as superoxide anion free radical (O2∙-, hydrogen peroxide (H2O2, and hydroxyl radical (HO∙, are produced at high levels and accumulated to cause oxidative stress (OS. In oxidative status, accumulated ROS can cause protein dysfunction and DNA damage, leading to gene mutations and cell death. Accumulated ROS could also act as chemical messengers to activate signaling pathways, such as NF-κB and p38 MAPK, to affect cell proliferation, differentiation, and apoptosis. More importantly, electrophilic carbonyl compounds produced by lipid peroxidation may function as secondary pathogenic factors, causing further protein and membrane lesions. This may in turn exaggerate oxidative stress, forming a vicious cycle. Electrophilic carbonyls could also cause DNA mutations and breaks, driving malignant progression of UC. The secondary lesions caused by carbonyl compounds may be exceptionally important in the case of host carbonyl defensive system deficit, such as aldo-keto reductase 1B10 deficiency. This review article updates the current understanding of oxidative stress and carbonyl lesions in the development and progression of UC and CAC.

  17. Direct photolysis of carbonyl compounds dissolved in cloud and fog droplets (United States)

    Epstein, S. A.; Tapavicza, E.; Furche, F.; Nizkorodov, S. A.


    Gas phase photolysis is an important tropospheric sink for many carbonyl compounds, however the significance of direct photolysis of carbonyl compounds dissolved in cloud and fog droplets is uncertain. We develop a theoretical approach to assess the importance of aqueous photolysis for a series of carbonyls that possess carboxyl and hydroxyl functional groups by comparison with rates of other atmospheric processes. We use computationally and experimentally derived Henry's law parameters, hydration equilibrium parameters, aqueous hydroxyl radical (OH) rate constants, and optical extinction coefficients to identify types of compounds that will not have competitive aqueous photolysis rates. We also present molecular dynamics simulations of atmospherically relevant carbonyl compounds designed to estimate gas and aqueous phase extinction coefficients. In addition, experiments designed to measure the photolysis rate of glyceraldehyde, an atmospherically relevant water soluble organic compound, reveal that aqueous quantum yields are highly molecule-specific and cannot be extrapolated from measurements of structurally similar compounds. We find that only three out of the 92 carbonyl compounds investigated, pyruvic acid, 3-oxobutanoic acid, and 3-oxopropanoic acid, may have aqueous photolysis rates that exceed the rate of oxidation by dissolved OH. For almost all carbonyl compounds lacking α, β conjugation, atmospheric removal by direct photolysis in cloud and fog droplets can be neglected.

  18. A biotin enrichment strategy identifies novel carbonylated amino acids in proteins from human plasma. (United States)

    Havelund, Jesper F; Wojdyla, Katarzyna; Davies, Michael J; Jensen, Ole N; Møller, Ian Max; Rogowska-Wrzesinska, Adelina


    Protein carbonylation is an irreversible protein oxidation correlated with oxidative stress, various diseases and ageing. Here we describe a peptide-centric approach for identification and characterisation of up to 14 different types of carbonylated amino acids in proteins. The modified residues are derivatised with biotin-hydrazide, enriched and characterised by tandem mass spectrometry. The strength of the method lies in an improved elution of biotinylated peptides from monomeric avidin resin using hot water (95°C) and increased sensitivity achieved by reduction of analyte losses during sample preparation and chromatography. For the first time MS/MS data analysis utilising diagnostic biotin fragment ions is used to pinpoint sites of biotin labelling and improve the confidence of carbonyl peptide assignments. We identified a total of 125 carbonylated residues in bovine serum albumin after extensive in vitro metal ion-catalysed oxidation. Furthermore, we assigned 133 carbonylated sites in 36 proteins in native human plasma protein samples. The optimised workflow enabled detection of 10 hitherto undetected types of carbonylated amino acids in proteins: aldehyde and ketone modifications of leucine, valine, alanine, isoleucine, glutamine, lysine and glutamic acid (+14Da), an oxidised form of methionine - aspartate semialdehyde (-32Da) - and decarboxylated glutamic acid and aspartic acid (-30Da).

  19. Protein carbonylation, protein aggregation and neuronal cell death in a murine model of multiple sclerosis (United States)

    Dasgupta, Anushka

    Many studies have suggested that oxidative stress plays an important role in the pathophysiology of both multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). Yet, the mechanism by which oxidative stress leads to tissue damage in these disorders is unclear. Recent work from our laboratory has revealed that protein carbonylation, a major oxidative modification caused by severe and/or chronic oxidative stress conditions, is elevated in MS and EAE. Furthermore, protein carbonylation has been shown to alter protein structure leading to misfolding/aggregation. These findings prompted me to hypothesize that carbonylated proteins, formed as a consequence of oxidative stress and/or decreased proteasomal activity, promote protein aggregation to mediate neuronal apoptosis in vitro and in EAE. To test this novel hypothesis, I first characterized protein carbonylation, protein aggregation and apoptosis along the spinal cord during the course of myelin-oligodendrocyte glycoprotein (MOG)35-55 peptide-induced EAE in C57BL/6 mice [Chapter 2]. The results show that carbonylated proteins accumulate throughout the course of the disease, albeit by different mechanisms: increased oxidative stress in acute EAE and decreased proteasomal activity in chronic EAE. I discovered not only that there is a temporal correlation between protein carbonylation and apoptosis but also that carbonyl levels are significantly higher in apoptotic cells. A high number of juxta-nuclear and cytoplasmic protein aggregates containing the majority of the oxidized proteins are also present during the course of EAE, which seems to be due to reduced autophagy. In chapter 3, I show that when gluthathione levels are reduced to those in EAE spinal cord, both neuron-like PC12 (nPC12) cells and primary neuronal cultures accumulate carbonylated proteins and undergo cell death (both by necrosis and apoptosis). Immunocytochemical and biochemical studies also revealed a temporal

  20. Fluorinated alcohols as promoters for the metal-free direct substitution reaction of allylic alcohols with nitrogenated, silylated, and carbon nucleophiles. (United States)

    Trillo, Paz; Baeza, Alejandro; Nájera, Carmen


    The direct allylic substitution reaction using allylic alcohols in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) and 2,2,2-trifluoroethanol (TFE) as reaction media is described. The developed procedure is simple, works under mild conditions (rt, 50 and 70 °C), and proves to be very general, since different nitrogenated nucleophiles and carbon nucleophiles can be used achieving high yields, especially when HFIP is employed as solvent and aromatic allylic alcohols are the substrates. Thus, sulfonamides, carbamates, carboxamides, and amines can be successfully employed as nitrogen-based nucleophiles. Likewise, silylated nucleophiles such as trimethylsilylazide, allyltrimethylsilane, trimethylsilane, and trimethylsilylphenylacetylene give the corresponding allylic substitution products in high yields. Good results for the Friedel-Crafts adducts are also achieved with aromatic compounds (phenol, anisole, indole, and anilines) as nucleophiles. Particularly interesting are the results obtained with electron-rich anilines, which can behave as nitrogenated or carbon nucleophiles depending on their electronic properties and the solvent employed. In addition, 1,3-dicarbonyl compounds (acetylacetone and Meldrum's acid) are also successfully employed as soft carbon nucleophiles. Studies for mechanism elucidation are also reported, pointing toward the existence of carbocationic intermediates and two working reaction pathways for the obtention of the allylic substitution product.

  1. Allyl/propenyl phenol synthases from the creosote bush and engineering production of specialty/commodity chemicals, eugenol/isoeugenol, in Escherichia coli. (United States)

    Kim, Sung-Jin; Vassão, Daniel G; Moinuddin, Syed G A; Bedgar, Diana L; Davin, Laurence B; Lewis, Norman G


    The creosote bush (Larrea tridentata) harbors members of the monolignol acyltransferase, allylphenol synthase, and propenylphenol synthase gene families, whose products together are able to catalyze distinct regiospecific conversions of various monolignols into their corresponding allyl- and propenyl-phenols, respectively. In this study, co-expression of a monolignol acyltransferase with either substrate versatile allylphenol or propenylphenol synthases in Escherichia coli established that various monolignol substrates were efficiently converted into their corresponding allyl/propenyl phenols, as well as providing proof of concept for efficacious conversion in a bacterial platform. This capability thus potentially provides an alternate source to these important plant phytochemicals, whether for flavor/fragrance and fine chemicals, or ultimately as commodities, e.g., for renewable energy or other intermediate chemical purposes. Previous reports had indicated that specific and highly conserved amino acid residues 84 (Phe or Val) and 87 (Ile or Tyr) of two highly homologous allyl/propenyl phenol synthases (circa 96% identity) from a Clarkia species mainly dictate their distinct regiospecific catalyzed conversions to afford either allyl- or propenyl-phenols, respectively. However, several other allyl/propenyl phenol synthase homologs isolated by us have established that the two corresponding amino acid 84 and 87 residues are not, in fact, conserved.

  2. Fast retrievals of tropospheric carbonyl sulfide with IASI (United States)

    Vincent, R. Anthony; Dudhia, Anu


    Iterative retrievals of trace gases, such as carbonyl sulfide (OCS), from satellites can be exceedingly slow. The algorithm may even fail to keep pace with data acquisition such that analysis is limited to local events of special interest and short time spans. With this in mind, a linear retrieval scheme was developed to estimate total column amounts of OCS at a rate roughly 104 times faster than a typical iterative retrieval. This scheme incorporates two concepts not utilized in previously published linear estimates. First, all physical parameters affecting the signal are included in the state vector and accounted for jointly, rather than treated as effective noise. Second, the initialization point is determined from an ensemble of atmospheres based on comparing the model spectra to the observations, thus improving the linearity of the problem. All of the 2014 data from the Infrared Atmospheric Sounding Interferometer (IASI), instruments A and B, were analysed and showed spatial features of OCS total columns, including depletions over tropical rainforests, seasonal enhancements over the oceans, and distinct OCS features over land. Error due to assuming linearity was found to be on the order of 11 % globally for OCS. However, systematic errors from effects such as varying surface emissivity and extinction due to aerosols have yet to be robustly characterized. Comparisons to surface volume mixing ratio in situ samples taken by NOAA show seasonal correlations greater than 0.7 for five out of seven sites across the globe. Furthermore, this linear scheme was applied to OCS, but may also be used as a rapid estimator of any detectable trace gas using IASI or similar nadir-viewing instruments.

  3. Intramolecular Hydrogen Bond in Biologically Active o-Carbonyl Hydroquinones

    Directory of Open Access Journals (Sweden)

    Maximiliano Martínez-Cifuentes


    Full Text Available Intramolecular hydrogen bonds (IHBs play a central role in the molecular structure, chemical reactivity and interactions of biologically active molecules. Here, we study the IHBs of seven related o-carbonyl hydroquinones and one structurally-related aromatic lactone, some of which have shown anticancer and antioxidant activity. Experimental NMR data were correlated with theoretical calculations at the DFT and ab initio levels. Natural bond orbital (NBO and molecular electrostatic potential (MEP calculations were used to study the electronic characteristics of these IHB. As expected, our results show that NBO calculations are better than MEP to describe the strength of the IHBs. NBO energies (∆Eij(2 show that the main contributions to energy stabilization correspond to LPàσ* interactions for IHBs, O1…O2-H2 and the delocalization LPàπ* for O2-C2 = Cα(β. For the O1…O2-H2 interaction, the values of ∆Eij(2 can be attributed to the difference in the overlap ability between orbitals i and j (Fij, instead of the energy difference between them. The large energy for the LP O2àπ* C2 = Cα(β interaction in the compounds 9-Hydroxy-5-oxo-4,8, 8-trimethyl-l,9(8H-anthracenecarbolactone (VIII and 9,10-dihydroxy-4,4-dimethylanthracen-1(4H-one (VII (55.49 and 60.70 kcal/mol, respectively when compared with the remaining molecules (all less than 50 kcal/mol, suggests that the IHBs in VIII and VII are strongly resonance assisted.

  4. Metabolism of bupropion by carbonyl reductases in liver and intestine. (United States)

    Connarn, Jamie N; Zhang, Xinyuan; Babiskin, Andrew; Sun, Duxin


    Bupropion's metabolism and the formation of hydroxybupropion in the liver by cytochrome P450 2B6 (CYP2B6) has been extensively studied; however, the metabolism and formation of erythro/threohydrobupropion in the liver and intestine by carbonyl reductases (CR) has not been well characterized. The purpose of this investigation was to compare the relative contribution of the two metabolism pathways of bupropion (by CYP2B6 and CR) in the subcellular fractions of liver and intestine and to identify the CRs responsible for erythro/threohydrobupropion formation in the liver and the intestine. The results showed that the liver microsome generated the highest amount of hydroxybupropion (Vmax = 131 pmol/min per milligram, Km = 87 μM). In addition, liver microsome and S9 fractions formed similar levels of threohydrobupropion by CR (Vmax = 98-99 pmol/min per milligram and Km = 186-265 μM). Interestingly, the liver has similar capability to form hydroxybupropion (by CYP2B6) and threohydrobupropion (by CR). In contrast, none of the intestinal fractions generate hydroxybupropion, suggesting that the intestine does not have CYP2B6 available for metabolism of bupropion. However, intestinal S9 fraction formed threohydrobupropion to the extent of 25% of the amount of threohydrobupropion formed by liver S9 fraction. Enzyme inhibition and Western blots identified that 11β-dehydrogenase isozyme 1 in the liver microsome fraction is mainly responsible for the formation of threohydrobupropion, and in the intestine AKR7 may be responsible for the same metabolite formation. These quantitative comparisons of bupropion metabolism by CR in the liver and intestine may provide new insight into its efficacy and side effects with respect to these metabolites.

  5. Soil fluxes of carbonyl sulfide (COS) across four distinct ecosystems (United States)

    Sun, W.; Maseyk, K. S.; Lett, C.; Juarez, S.; Kooijmans, L.; Mammarella, I.; Vesala, T.; Chen, H.; Seibt, U.


    Soils are additional but poorly resolved sinks of carbonyl sulfide (COS) in terrestrial ecosystems. COS has been proposed as a tracer for quantifying gross photosynthesis based on the coupled stomatal uptake of COS and CO2. But applying this tracer requires the soil COS flux to be subtracted from the ecosystem flux to obtain the actual plant flux. To simulate soil COS fluxes, we have built a 1-D diffusion-reaction model accounting for vertical transport in the soil, microbial sinks and sources, and a litter layer. Uptake and production of COS in the soil column are linked with soil temperature and moisture through empirical functions adapted from enzyme kinetics and lab incubations. We have measured soil COS fluxes and the related soil variables in four distinct ecosystems: a wheat field (Southern Great Plains, OK, USA), an oak woodland (Santa Monica Mountains, CA, USA), a tropical rainforest (La Selva Biological Station, Costa Rica) and a boreal pine forest (Hyytiälä, Finland). Across all sites, a lower soil temperature and a humid climate are generally favorable to soil COS uptake. Strong COS emissions were observed in the wheat field at high soil temperatures after harvesting but were absent in other ecosystems, indicating that COS exchange may behave differently in agricultural soils. We simulated the soil fluxes in all ecosystems using the diffusion-reaction model, and optimized the source/sink strength parameters with field data. The optimized model provides insights that are not attainable from data analysis alone: For example, the wheat field soil must have continued uptake activity even when it showed net emissions, and leaf litter contributed dominantly to the COS sink after rain in the oak woodland. We expect the new model to be useful for simulating global soil COS fluxes as field data on soil fluxes from a broader range of ecosystems become available.

  6. Organometallic and Bioorganometallic Chemistry - Ferrocene and Metal Carbonyls

    Directory of Open Access Journals (Sweden)

    Čakić Semenčić, M.


    Full Text Available Organometallic chemistry deals with compounds containing metal-carbon bonds. Basic organometallics derived from the s- and p-block metals (containing solely σ-bonds were understood earlier, while organometallic chemistry of the d- and f-block has developed much more recently. These compounds are characterized by three types of M-C bonds (σ, π and δand their structures are impossible to deduce by chemical means alone; fundamental advances had to await the development of X-ray diffraction, as well as IR- and NMR-spectroscopy. On the other hand, elucidation of the structure of e. g. vitamin B12 and ferrocene (discovered in 1951 contributed to progress in these instrumental analytical methods, influencing further phenomenal success of transition-metal organometallic chemistry in the second half of the twentieth century. The most thoroughly explored fields of application of organometallics were in the area of catalysis, asymmetric synthesis, olefin metathesis, as well as organic synthesis and access to new materials and polymers.The most usual ligands bound to d- and f-metals are carbon monoxide, phosphines, alkyls, carbenes and arenes, and in this review the bonding patterns in the metal carbonyls and ferrocene are elaborated. The common characteristics of these two classes are two-component bonds. The CO-M bonds include (i donation from ligand HOMO to vacant M d-orbitals (σ-bond, and (ii back-donation from the filled M d-orbitals in the ligand LUMO (π-bond. Similar (but much more complicated ferrocene contains delocalized bonds consisting of electron donation from Cp to Fe (σ-bonds- and π-bonding and δ-back-bonding from metal to Cp. In such a way ferrocene, i. e. (η5-Cp2Fe contains 18 bonding electrons giving to this compound "superaromatic" properties in the sense of stability and electrophilic substitution. In contrast to benzenoid aromatic compounds reactions in two Cp-rings can occur giving homo- and heteroannularly mono-, two-… per

  7. A convenient method for the synthesis of (prop-2-ynyloxybenzene derivatives via reaction with propargyl bromide, their optimization, scope and biological evaluation.

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    Tannaza Batool

    Full Text Available A highly convenient method has been developed for the synthesis of (prop-2-ynyloxy benzene and its derivatives. Differently substituted phenol and aniline derivatives were allowed to react with propargyl bromide in the presence of K2CO3 base and acetone as solvent. The compounds were synthesized in good yields (53-85%. Low cost, high yields and easy availability of compounds helped in the synthesis. Electron withdrawing groups favor the formation of stable phenoxide ion thus in turn favors the formation of product while electron donating groups do not favor the reaction. Phenol derivatives gave good yields as compared to that of aniline. As aprotic polar solvents favor SN2 type reactions so acetone provided best solvation for the reactions. K2CO3 was proved to be good for the synthesis. Antibacterial, Antiurease and NO scavenging activity of synthesized compounds were also examined. 4-bromo-2-chloro-1-(prop-2-ynyloxybenzene 2a was found most active compound against urease enzyme with a percentage inhibition of 82.00±0.09 at 100 µg/mL with IC50 value of 60.2. 2-bromo-4-methyl-1-(prop-2-ynyloxybenzene 2d was found potent antibacterial against Bacillus subtillus showing excellent inhibitory action with percentage inhibition of 55.67±0.26 at 100 µg/ml wih IC50 value of 79.9. Based on results, it can be concluded that some of the synthesized compounds may have potential antiurease and antibacterial effects against several harmful substances.

  8. A convenient method for the synthesis of (prop-2-ynyloxy)benzene derivatives via reaction with propargyl bromide, their optimization, scope and biological evaluation. (United States)

    Batool, Tannaza; Rasool, Nasir; Gull, Yasmeen; Noreen, Mnaza; Nasim, Faiz-ul-Hassan; Yaqoob, Asma; Zubair, Muhammad; Rana, Usman Ali; Khan, Salah Ud-Din; Zia-Ul-Haq, M; Jaafar, Hawa Z E


    A highly convenient method has been developed for the synthesis of (prop-2-ynyloxy) benzene and its derivatives. Differently substituted phenol and aniline derivatives were allowed to react with propargyl bromide in the presence of K2CO3 base and acetone as solvent. The compounds were synthesized in good yields (53-85%). Low cost, high yields and easy availability of compounds helped in the synthesis. Electron withdrawing groups favor the formation of stable phenoxide ion thus in turn favors the formation of product while electron donating groups do not favor the reaction. Phenol derivatives gave good yields as compared to that of aniline. As aprotic polar solvents favor SN2 type reactions so acetone provided best solvation for the reactions. K2CO3 was proved to be good for the synthesis. Antibacterial, Antiurease and NO scavenging activity of synthesized compounds were also examined. 4-bromo-2-chloro-1-(prop-2-ynyloxy)benzene 2a was found most active compound against urease enzyme with a percentage inhibition of 82.00±0.09 at 100 µg/mL with IC50 value of 60.2. 2-bromo-4-methyl-1-(prop-2-ynyloxy)benzene 2d was found potent antibacterial against Bacillus subtillus showing excellent inhibitory action with percentage inhibition of 55.67±0.26 at 100 µg/ml wih IC50 value of 79.9. Based on results, it can be concluded that some of the synthesized compounds may have potential antiurease and antibacterial effects against several harmful substances.

  9. Preclinical assessment of the distribution,metabolism, and excretion of S-propargyl-cysteine, a novel H2S donor, in Sprague-Dawley rats

    Institute of Scientific and Technical Information of China (English)

    Yuan-ting ZHENG; Yi-zhun ZHU; Wei-min CAI; Jian-hua ZHU; Guo MA; Qing ZHU; Ping YANG; Bo TAN; Jin-lian ZHANG; Hai-xing SHEN; Jia-lin XU


    Aim:To study the distribution,metabolism and excretion of S-propargyl-cysteine (SPRC),a novel hydrogen sulfide (H2S) donor,after oral administration in rats.Methods:Adult Sprague-Dawley rats were used.The tissue distribution of [35S] SPRC-derived radioactivity was measured using a liquid scintillation counter.The plasma protein binding of SPRC was examined using 96-well equilibrium dialysis.The excretion of SPRC in urine,bile and feces was analyzed using the LC-MS/MS method.The major metabolites in rat biomatrices were identified using MRM information-dependent,acquisition-enhanced product ion (MRM-IDA-EPI) scans on API 4000QTrap system.Results:After oral administration of [35S] SPRC at a dose of 75 mg/kg,[35S] SPRC-derived radioactivity displayed broad biological distribution in various tissues of rats,including its target organs (heart and brain) with the highest in kidney.On the other hand,the binding of SPRC to human,rat and dog plasma protein was low.Only 2.18%±0.61% and 0.77%±0.61% of the total SPRC administered was excreted unchanged in the bile and urine.However,neither intact SPRC nor its metabolites were detected in rat feces.The major metabolic pathway in vivo (rat bile,urine,and plasma) was N-acetylation.Conclusion:The preliminary results suggest that SPRC possesses acceptable pharmacokinetic properties in rats.

  10. Activity of a novel anti-folate (PDX, 10-propargyl 10-deazaaminopterin) against human lymphoma is superior to methotrexate and correlates with tumor RFC-1 gene expression. (United States)

    Wang, Eunice S; O'Connor, Owen; She, Yuhong; Zelenetz, Andrew D; Sirotnak, F M; Moore, Malcolm A S


    PDX (10-propargyl-10-deazaaminopterin) is a novel anti-folate with improved membrane transport and polyglutamylation in tumor cells. In prior studies, PDX exhibited enhanced efficacy over methotrexate (MTX) in lung and breast carcinoma xenografts. Because MTX is active in the treatment of aggressive non-Hodgkin's lymphoma (NHL), we compared the efficacy of PDX and MTX against five lymphoma cell lines: RL (transformed follicular lymphoma), HT, SKI-DLBCL-1 (diffuse large B cell), Raji (Burkitt's), and Hs445 (Hodgkin's disease). After 5-day continuous in vitro exposure, PDX demonstrated > 10-fold greater cytotoxicity than MTX in all cell lines (IC50PDX = 3-5 nM, IC50MTX = 30-50 nM). We then compared the in vivo effects of anti-folates against three established human NHL xenografts in NOD/SCID mice. Tumor bearing animals were treated with saline (control) or the maximum tolerated doses of MTX (40 mg/kg) or PDX (60 mg/kg) via an intraperitoneal route twice weekly for 2 weeks. Almost 90% of HT lymphomas treated with PDX completely regressed, whereas, those treated with MTX treatment had only modest growth delays. In two other xenografts, tumor bearing mice had complete regression rates of 56% (RL) and 30% (SKI-DLBCL-1) after PDX therapy. No regressions and only minor growth inhibition was noted after MTX therapy. RT-PCR analysis for the expression of genes involved in folate metabolism demonstrated that increased sensitivity to PDX correlated with higher RFC-1 gene expression with no difference in FPGS or FPGH levels, suggesting that measurement of tumor RFC-1 gene expression level may be a predictor of response to PDX. These results demonstrate that the PDX has markedly greater potential activity against human NHL than MTX and warrants further preclinical and clinical evaluation.

  11. Concentrations of formaldehyde and other carbonyls in environments affected by incense burning. (United States)

    Ho, Steven Sai Hang; Yu, Jian Zhen


    Burning incense to pay homage to deities is common in Chinese homes and temples. Air samples were collected and analyzed for carbonyls from a home and a temple in Hong Kong where incense burning occurs on a daily basis. Carbonyls in the air were trapped on a solid sorbent coated with O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine, followed by thermal desorption and subsequent GC/MS analysis. The carbonyls identified include formaldehyde, acetaldehyde, acrolein, 2-furfural, benzaldehyde, glyoxal, and methylglyoxal. The levels of the above carbonyls correlate with the intensity of the incense-burning activities. The total mixing ratios of the carbonyls in the temple exceed those in the ambient air outside the temple by 11-23 times. Formaldehyde is the most abundant species, contributing to approximately 55% of the total carbonyl mixing ratios in both the temple and the home environments during incense burning. The mixing ratio of formaldehyde ranges from 108 to 346 ppbv in the temple and averages 103 ppbv in the home during incense burning. These values exceed the World Health Organization (WHO) air quality guideline of 100 microg m(-3) (88 ppbv) for formaldehyde. The highest formaldehyde level in the temple exceeds the WHO guideline by 3 times at peak incense burning hours. The mixing ratio of acrolein in the temple ranges from 20 to 99 ppbv, approaching or exceeding the WHO air quality guideline of 50 microg m(-3) (22 ppbv) for acrolein. Our measurements indicate that incense burning significantly elevates the concentrations of a number of carbonyls, most notably formaldehyde and acrolein, in the surrounding environments. This study provides preliminary insights on indoor air quality problems created by incense burning.

  12. Proteomic identification of carbonylated proteins in F344 rat hippocampus after 1-bromopropane exposure

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Zhenlie [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan); Department of Toxicology, Guangdong Prevention and Treatment Center for Occupational Diseases, Guangzhou 510‐300 (China); Ichihara, Sahoko [Graduate School of Regional Innovation Studies, Mie University, Tsu 514‐8507 (Japan); Oikawa, Shinji [Department of Environmental and Molecular Medicine, Mie University Graduate School of Medicine, Mie 514‐8507 (Japan); Chang, Jie; Zhang, Lingyi; Subramanian, Kaviarasan; Mohideen, Sahabudeen Sheik [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan); Ichihara, Gaku, E-mail: [Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya 466‐8550 (Japan)


    1-Bromopropane (1-BP) is neurotoxic in both experimental animals and humans. Previous proteomic analysis of rat hippocampus implicated alteration of protein expression in oxidative stress, suggesting that oxidative stress plays a role in 1-BP-induced neurotoxicity. To understand this role at the protein level, we exposed male F344 rats to 1-BP at 0, 400, or 1000 ppm for 8 h/day for 1 week or 4 weeks by inhalation and quantitated changes in hippocampal protein carbonyl using a protein carbonyl assay, two-dimensional gel electrophoresis (2-DE), immunoblotting, and matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-TOF/MS). Hippocampal reactive oxygen species and protein carbonyl were significantly increased, demonstrating 1-BP-associated induction of oxidative stress and protein damage. MALDI-TOF-TOF/MS identified 10 individual proteins with increased carbonyl modification (p < 0.05; fold-change ≥ 1.5). The identified proteins were involved in diverse biological processes including glycolysis, ATP production, tyrosine catabolism, GTP binding, guanine degradation, and neuronal metabolism of dopamine. Hippocampal triosephosphate isomerase (TPI) activity was significantly reduced and negatively correlated with TPI carbonylation (p < 0.001; r = 0.83). Advanced glycation end-product (AGE) levels were significantly elevated both in the hippocampus and plasma, and hippocampal AGEs correlated negatively with TPI activity (p < 0.001; r = 0.71). In conclusion, 1-BP-induced neurotoxicity in the rat hippocampus seems to involve oxidative damage of cellular proteins, decreased TPI activity, and elevated AGEs. -- Highlights: ► 1-BP increases hippocampal ROS levels and hippocampal and plasma protein carbonyls. ► 1-BP increases TPI carbonylation and decreases TPI activity in the hippocampus. ► 1-BP increases hippocampal and plasma AGE levels.

  13. S-Allyl-Cysteines Reduce Amelioration of Aluminum Induced Toxicity in Rats

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    Sadhana Shrivastava


    Full Text Available Problem statement: Aluminum (Al is a trivalent cation found in its ionic form in most kinds of animal tissues and in natural waters everywhere. Approach: It is a potent neurotoxin and has been associated in the pathogenesis of several clinical disorders including Alzheimer’s disease. Results: The aim of the study was to demonstrate the protective effect of S-Allyl-Cysteines (SAC against Al-induced toxicity in rat model on certain biochemical parameters, lipid peroxidation and oxidative stress enzymes of white albino rats. Six rats per group were divided into various treatment groups. Group one rats were given normal saline and served as control group. Group two animals received Al as aluminum nitrate 32.5 mg (i.p. for the induction of toxicity. Group three to five received different doses of SAC (25, 50 and 100 mg kg-1 for 3 days after 24 h of Al toxicity. Rats were orally administered their respective doses every day for 3 days. Evaluations were made in blood and tissues. The activity of Acetylcholinesterase (AchE was inhibited in all the parts of brain after Al intoxication. Significant rise were observed the Activities of Serum Transaminases (AST and ALT after toxicant exposure. The activity of â-Aminolevulinic acid Dehydratase (ALAD in blood and â-Aminolevulinic Acid Synthetase (ALAS in brain was decreased after Al exposure. Al significant increased cholesterol, triglyceride, creatinine and urea level in serum. TBARS level was significantly higher and GSH content were significantly lower during toxicity. Total and esterified cholesterol in liver, kidney and brain were increased after Al exposure. Histopathological changes in liver, kidney and brain were also recouped with the therapy. Conclusion/Recommendations: Our data proved that SAC which is a bioactive and bioavailable component of garlic has organosulfur compounds which regulates the thiol status of the cell and scavenges free radicals and work as an antioxidant. Thus SAC

  14. New copolymer of acrylamide with allyl methacrylate and its capacity for the removal of azo dyes

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    Yeliz Yildirim


    Full Text Available The copolymerization reactions of Acrylamide (AA with the different mole ratios of allyl methacrylate (AMA such as 25/75, 50/50 and 75/25 were studied by radical polymerization under argon atmosphere using 2,2’-Azobis (isobutyronitri1e (AIBN as initiator. The copolymers were characterized with Fourier transform infrared spectroscopy (FTIR and thermogravimetric analysis (TG. FTIR spectra showed that the C=O, C-N and N-H groups in copolymers remained during the copolymerization. It is concluded from the thermograms that Poly(AA-co-AMA copolymers which contained different ratios of monomer and comonomer exhibit similar thermal behavior. Adsorption capacity, kinetic and isotherm studies of Direct Brown 2 onto the copolymers have been evaluated. Different factors such as the monomer ratio, pH, initial dye concentration, copolymer dosage and contact time affecting the removal process were studied. It was found that the adsorption process agreed with the Freundlich and Dubinin-Raduskevich model and the adsorption of Direct Brown 2 depended on the acrylamide content and pH of the solution. The standard Gibb’s free energy was determined as - 14.7 kJ/mol, which means that adsorption occurred spontaneously and the process is feasible. Increasing the acrylamide content led to increased adsorption of Direct Brown 2 on the copolymer. Moreover, adsorption kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model, indicating that the chemical adsorption was the rate-limiting step. These results show that Poly(AA-co-AMA can be used as adsorbent for water pollutants such as Direct Brown 2 and has potential applications in related industrial and environmental areas.

  15. Stereoselective coordination: a six-membered P,N-chelate tailored for asymmetric allylic alkylation. (United States)

    Császár, Z; Farkas, G; Bényei, A; Lendvay, G; Tóth, I; Bakos, J


    Six-membered chelate complexes [Pd(1a-b)Cl2], (2a-b) and [Pd(1a-b)(η(3)-PhCHCHCHPh)]BF4, (3a-b) of P,N-type ligands 1a, ((2S,4S)-2-diphenyl-phosphino-4-isopropylamino-pentane) and 1b, ((2S,4S)-2-diphenyl-phosphino-4-methylamino-pentane) have been prepared. The Pd-complexes have been characterized in solution by 1D and 2D NMR spectroscopy. The observed structures were confirmed by DFT calculations and in the case of 2a also by X-ray crystallography. Unexpectedly, the coordination of the all-carbon-backbone aminophosphine 1a resulted in not only a stereospecific locking of the donor nitrogen atom into one of the two possible configurations but also the conformation of the six-membered chelate rings containing three alkyl substituents was forced into the same single chair structure showing the axially placed isopropyl group on the coordinated N-atom. The stereodiscriminative complexation of 1a led to the formation of a palladium catalyst with a conformationally rigid chelate having a configurationally fixed nitrogen and electronically different coordination sites due to the presence of P and N donors. The stereochemically fixed catalyst provided excellent ee's (up to 96%) and activities in asymmetric allylic alkylation reactions. In contrast, the chelate rings formed by 1b exist in two different chair conformations, both containing axial methyl groups, but with the opposite configurations of the coordinated N-atom. Pd-complexes of 1b provided low enantioselectivities in similar alkylations, therefore emphasizing the importance of the stereoselective coordination of N-atoms in analogous P-N chelates. The factors determining the coordination of the ligands were also studied with respect to the chelate ring conformation and the nitrogen configuration.

  16. Mechanisms of transient receptor potential vanilloid 1 activation and sensitization by allyl isothiocyanate. (United States)

    Gees, Maarten; Alpizar, Yeranddy A; Boonen, Brett; Sanchez, Alicia; Everaerts, Wouter; Segal, Andrei; Xue, Fenqin; Janssens, Annelies; Owsianik, Grzegorz; Nilius, Bernd; Voets, Thomas; Talavera, Karel


    Allyl isothiocyanate (AITC; aka, mustard oil) is a powerful irritant produced by Brassica plants as a defensive trait against herbivores and confers pungency to mustard and wasabi. AITC is widely used experimentally as an inducer of acute pain and neurogenic inflammation, which are largely mediated by the activation of nociceptive cation channels transient receptor potential ankyrin 1 and transient receptor potential vanilloid 1 (TRPV1). Although it is generally accepted that electrophilic agents activate these channels through covalent modification of cytosolic cysteine residues, the mechanism underlying TRPV1 activation by AITC remains unknown. Here we show that, surprisingly, AITC-induced activation of TRPV1 does not require interaction with cysteine residues, but is largely dependent on S513, a residue that is involved in capsaicin binding. Furthermore, AITC acts in a membrane-delimited manner and induces a shift of the voltage dependence of activation toward negative voltages, which is reminiscent of capsaicin effects. These data indicate that AITC acts through reversible interactions with the capsaicin binding site. In addition, we show that TRPV1 is a locus for cross-sensitization between AITC and acidosis in nociceptive neurons. Furthermore, we show that residue F660, which is known to determine the stimulation by low pH in human TRPV1, is also essential for the cross-sensitization of the effects of AITC and low pH. Taken together, these findings demonstrate that not all reactive electrophiles stimulate TRPV1 via cysteine modification and help understanding the molecular bases underlying the surprisingly large role of this channel as mediator of the algesic properties of AITC.

  17. Elucidation of the regio- and chemoselectivity of enzymatic allylic oxidations with Pleurotus sapidus – conversion of selected spirocyclic terpenoids and computational analysis

    Directory of Open Access Journals (Sweden)

    Verena Weidmann


    Full Text Available Allylic oxidations of olefins to enones allow the efficient synthesis of value-added products from simple olefinic precursors like terpenes or terpenoids. Biocatalytic variants have a large potential for industrial applications, particularly in the pharmaceutical and food industry. Herein we report efficient biocatalytic allylic oxidations of spirocyclic terpenoids by a lyophilisate of the edible fungus Pleurotus sapidus. This ‘’mushroom catalysis’’ is operationally simple and allows the conversion of various unsaturated spirocyclic terpenoids. A number of new spirocyclic enones have thus been obtained with good regio- and chemoselectivity and chiral separation protocols for enantiomeric mixtures have been developed. The oxidations follow a radical mechanism and the regioselectivity of the reaction is mainly determined by bond-dissociation energies of the available allylic CH-bonds and steric accessibility of the oxidation site.

  18. Rheological and mechanical behavior of polyacrylamide hydrogels chemically crosslinked with allyl agarose for two-dimensional gel electrophoresis. (United States)

    Suriano, R; Griffini, G; Chiari, M; Levi, M; Turri, S


    Two-dimensional (2-D) gel electrophoresis currently represents one of the most standard techniques for protein separation. In addition to the most commonly employed polyacrylamide crosslinked hydrogels, acrylamide-agarose copolymers have been proposed as promising systems for separation matrices in 2-D electrophoresis, because of the good resolution of both high and low molecular mass proteins made possible by careful control and optimization of the hydrogel pore structure. As a matter of fact, a thorough understanding of the nature of the hydrogel pore structure as well as of the parameters by which it is influenced is crucial for the design of hydrogel systems with optimal sieving properties. In this work, a series of acrylamide-based hydrogels covalently crosslinked with different concentrations of allyl agarose (0.2-1%) is prepared and characterized by creep-recovery measurements, dynamic rheology and tensile tests, in the attempt to gain a clearer understanding of structure-property relationships in crosslinked polyacrylamide-based hydrogels. The rheological and mechanical properties of crosslinked acrylamide-agarose hydrogels are found to be greatly affected by crosslinker concentration. Dynamic rheological tests show that hydrogels with a percentage of allyl agarose between 0.2% and 0.6% have a low density of elastically effective crosslinks, explaining the good separation of high molecular mass proteins in 2-D gel electrophoresis. Over the same range of crosslinker concentration, creep-recovery measurements reveal the presence of non-permanent crosslinks in the hydrogel network that justifies the good resolution of low molecular mass proteins as well. In tensile tests, the hydrogel crosslinked with 0.4% of allyl agarose exhibits the best results in terms of mechanical strength and toughness. Our results show how the control of the viscoelastic and the mechanical properties of these materials allow the design of mechanically stable hydrogels with improved

  19. Antimicrobial activity of allyl isothiocyanate used to coat biodegradable composite films as affected by storage and handling conditions. (United States)

    Li, Weili; Liu, Linshu; Jin, Tony Z


    We evaluated the effects of storage and handling conditions on the antimicrobial activity of biodegradable composite films (polylactic acid and sugar beet pulp) coated with allyl isothiocyanate (AIT). Polylactic acid and chitosan were incorporated with AIT and used to coat one side of the film. The films were subjected to different storage conditions (storage time, storage temperature, and packed or unpacked) and handling conditions (washing, abrasion, and air blowing), and the antimicrobial activity of the films against Salmonella Stanley in tryptic soy broth was determined. The films (8.16 μl of AIT per cm(2) of surface area) significantly (P packaging.

  20. Tandem SN2' nucleophilic substitution/oxidative radical cyclization of aryl substituted allylic alcohols with 1,3-dicarbonyl compounds. (United States)

    Zhang, Zhen; Li, Cheng; Wang, Shao-Hua; Zhang, Fu-Min; Han, Xue; Tu, Yong-Qiang; Zhang, Xiao-Ming


    A novel and efficient tandem SN2' nucleophilic substitution/oxidative radical cyclization reaction of aryl substituted allylic alcohols with 1,3-dicarbonyl compounds has been developed by using Mn(OAc)3 as an oxidant, which enables the expeditious synthesis of polysubstituted dihydrofuran (DHF) derivatives in moderate to high yields. The use of weakly acidic hexafluoroisopropanol (HFIP) as the solvent rather than AcOH has successfully improved the yields and expanded the substrate scope of this type of radical cyclization reactions. Mechanistic studies confirmed the cascade reaction process involving a final radical cyclization.

  1. Positive trends in Southern Hemisphere observations of carbonyl sulfide (United States)

    Kremser, Stefanie; Jones, Nicholas; Smale, Dan; Palm, Mathias; Lejeune, Bernard; Wang, Yuting; Deutscher, Nicholas


    Carbonyl sulfide (OCS; lifetime of about 5.7 years) is the longest lived reduced sulfur-containing gas in the atmosphere. The primary source of OCS is the ocean, which is both a direct source (through OCS emission) and an indirect source (due to oxidation of carbon disulfide, CS2, and dimethyl sulfide). Other natural sources of OCS include volcanic outgassing and direct fluxes from wetland regions. The removal of OCS from the atmosphere is dominated by soil and vegetation uptake, with minor contributions from reactions with the hydroxyl radical. Small anthropogenic sources of OCS are coal combustion, biomass burning, and aluminum production. A dominant indirect source results from CS2 emissions from the rayon industry. Transport of tropospheric OCS to the stratosphere during volcanically quiescent periods has been suggested to contribute sulfur to the stratospheric aerosol layer which affects atmospheric radiative balance. If, however, production of stratospheric aerosols from OCS oxidation is smaller than typical estimates, this OCS contribution would be overestimated. The magnitude of the OCS flux to the stratosphere is currently not well quantified as is the relative contribution of OCS to background aerosol loading. While earlier model simulations indicate OCS fluxes into the atmosphere exceeding removal, past total column observations of OCS show no significant trend. Analysis of tropospheric OCS columns at Arrival Heights (Antarctica) and Lauder (New Zealand) show strong positive trends from 2001-2008 followed by weaker trends to 2015, with unexpected temporal coherence. Since trends in ocean and land sources/sinks at these two sites, respectively, are unlikely to be similar, the coherence in trend structure likely results from changes in transport of OCS from the tropics to middle and high latitudes. Potential causes for OCS increases are (i) increases in tropical lower stratospheric OCS and/or (ii) strengthening of the large-scale circulation which

  2. Strong soil source of carbonyl sulfide in an agricultural field (United States)

    Maseyk, K. S.; Seibt, U.; Berry, J. A.; Billesbach, D. P.; Campbell, J.; Torn, M. S.


    A promising new approach to constrain biosphere-atmosphere carbon and water exchange is the use of carbonyl sulfide (COS). COS is taken up by leaves via the same pathway as CO2, leading to a close coupling of vegetation COS and CO2 fluxes during photosynthesis. Therefore it has been proposed that the gross fluxes of photosynthesis and respiration can be quantified through the concurrent measurements of COS and CO2. A necessary requirement for this approach at ecosystem and continental scales are estimates of soil COS fluxes. Soil is largely considered a sink for COS, but our knowledge of in situ soil COS fluxes remains very limited. We measured soil COS fluxes in a wheat field in Oklahoma from April to June 2012, using a novel combination of an automated soil chamber coupled to a COS laser analyzer. We provide the first continuous record of soil COS fluxes under natural conditions, and report on a phenomenon that has not been observed before. In contrast to the majority of published results, we found that the agricultural soil was a strong source of COS under most conditions during the campaign. The COS flux over the study period was highly correlated with soil temperature. Up to a soil temperature of around 15°C, the soil acted as a COS sink. Above 15°C, it acted a source of COS, with fluxes of up to 25 pmol m-2 s-1. To locate the source of the COS production, we investigated different soil components. Wheat roots were found to be emitting COS under all conditions. Root-free soil was a COS sink up to a soil temperature of around 25°C, but turned into a COS source at higher soil temperatures. We also observed COS production from the roots of several other species, indicating that this may be a widespread phenomenon. Using eddy covariance data of COS and CO2 that was collected concurrently with the soil measurements, we also demonstrate how the soil COS source can be taken into account when partitioning net ecosystem exchange into photosynthesis and respiration.


    Institute of Scientific and Technical Information of China (English)

    陈春武; 谢令德; 陈雅群; 何君; 贺艳萍


    以玉米象和赤拟谷盗作为实验对象,采用熏蒸方式对烯丙基异硫氰酸酯的毒力进行测定.结果表明,烯丙基异硫氰酸酯对所研究的两种害虫有较好的快速致死作用,同时研究发现在相同熏蒸时间内烯丙基异硫氰酸酯对玉米象熏蒸的LC50和LC99均小于对赤拟谷盗的LC50和LC99,这说明烯丙基异硫氰酸酯对玉米象的熏蒸效果比对赤拟谷盗的好.%Chosing Si tophilus zesmais (Motschulsky) and Tribolium castaneun (Herbst) as experimental objects, the toxicity for the allyl isothiocyanate (AITC) is tested systematically by fumigation method. The result demonstrates that the allyl isothiocyanate presents rapid lethal effect against both of the two types of insects. The research also shows that both the LC50 and the LC99 of the fumigation of the allyl isothiocyanate to the Sitophilus zeamais are less than those of the allyl isothiocyanate to the Tribolium castaneum exposuring the same fumigating time, which indicates that the fumigating effect of the allyl isothiocyanate to the Sitophilus zeamais is more effective than that of the allyl isothiocyanate to the Tribolium castaneum.

  4. The utilization of the mesoporous Ti-SBA-15 catalyst in the epoxidation of allyl alcohol to glycidol and diglycidyl ether in the water medium

    Directory of Open Access Journals (Sweden)

    Wróblewska Agnieszka


    Full Text Available This work presents the studies on the optimization the process of allyl alcohol epoxidation over the Ti-SBA-15 catalyst. The optimization was carried out in an aqueous medium, wherein water was introduced into the reaction medium with an oxidizing agent (30 wt% aqueous solution of hydrogen peroxide and it was formed in the reaction medium during the processes. The main investigated technological parameters were: the temperature, the molar ratio of allyl alcohol/hydrogen peroxide, the catalyst content and the reaction time. The main functions the process were: the selectivity of transformation to glycidol in relation to allyl alcohol consumed, the selectivity of transformation to diglycidyl ether in relation to allyl alcohol consumed, the conversion of allyl alcohol and the selectivity of transformation to organic compounds in relation to hydrogen peroxide consumed. The analysis of the layer drawings showed that in water solution it is best to conduct allyl alcohol epoxidation in direction of glycidol (selectivity of glycidol 54 mol% at: the temperature of 10–17°C, the molar ratio of reactants 0.5–1.9, the catalyst content 2.9–4.0 wt%, the reaction time 2.7–3.0 h and in direction of diglycidyl ether (selectivity of diglycidyl ether 16 mol% at: the temperature of 18–33°C, the molar ratio of reactants 0.9–1.65, the catalyst content 2.0–3.4 wt%, the reaction time 1.7–2.6 h. The presented method allows to obtain two very valuable intermediates for the organic industry.

  5. Green synthesis of allyl isobornyl ether%烯丙基异冰片基醚绿色合成研究

    Institute of Scientific and Technical Information of China (English)

    王士康; 徐徐; 兰蓝; 樊媛媛; 王石发


    以莰烯和烯丙醇为原料,研究了烯丙基异冰片基醚的绿色合成工艺,探讨了催化剂种类及用量、反应温度、反应时间,以及烯丙醇与莰烯物质的量之比对莰烯醚化反应选择性及烯丙基异冰片基醚产物得率的影响.采用正交试验方法确定了烯丙基异冰片基醚的最适工艺条件:A-15型阳离子树脂为催化剂,催化剂用量为烯丙醇和莰烯原料总质量的5%,烯丙醇与莰烯物质的量之比为1.5:1,反应温度75℃,反应时间7h.在此条件下工业莰烯转化率为85.5%,反应选择性为97.5%,烯丙基异冰片基醚得率为83.4%.最后采用GC-MS、IR等分析技术对合成所得产物的结构进行了分析测定.%Green synthetic method of allyl isobornyl ether was investigated by using camphene and allyl alcohol as the raw materials in this paper. Influence of catalysts and their usages, reaction temperature, reaction time, and the molar ratio of allyl alcohol to camphene on the selectivity of etherification and the yield of allyl isobornyl ether were examined, and the optimum synthesis conditions were determined based on the orthogonal test results as follows: A-15 resin was used as the catalyst for etherification, and the amount of A-15 cationic exchange resin was 5 % (based on the total weight of camphene and allyl alcohol) ; molar ratio of allyl alcohol to camphene was 1. 5-1; reaction temperature and reaction time were 75 ℃ and 7 h, respectively. The conversion ratio of camphene and the reaction selectivity reached 85. 5 % and 97. 5 % respectively, and the yield of allyl isobornyl ether also reached 83. 4 %. The structure of allyl isobornyl ether was identified by GC-MS and IR spectra.

  6. Use of Cyclic Allylic Bromides in the Zinc–Mediated Aqueous Barbier–Grignard Reaction

    Directory of Open Access Journals (Sweden)

    Suzanne M. Perala


    Full Text Available The zinc–mediated aqueous Barbier–Grignard reaction of cyclic allylic bromide substrates with various aldehydes and ketones to afford homoallylic alcohols was investigated. Aromatic aldehydes and ketones afforded adducts in good yields (66–90% and with good diastereoselectivities. Non–aromatic aldehydes also reacted well under these conditions, but only poor yields were obtained with non–aromatic ketones. Regioselectivity was high when some substituted cyclic allylic bromides were investigated.

  7. Fructose-Induced Carbonyl/Oxidative Stress in S. cerevisiae: Involvement of TOR. (United States)

    Valishkevych, Bohdana V; Vasylkovska, Ruslana A; Lozinska, Liudmyla M; Semchyshyn, Halyna M


    The TOR (target of rapamycin) signaling pathway first described in the budding yeast Saccharomyces cerevisiae is highly conserved in eukaryotes effector of cell growth, longevity, and stress response. TOR activation by nitrogen sources, in particular amino acids, is well studied; however its interplay with carbohydrates and carbonyl stress is poorly investigated. Fructose is a more potent glycoxidation agent capable of producing greater amounts of reactive carbonyl (RCS) and oxygen species (ROS) than glucose. The increased RCS/ROS production, as a result of glycoxidation in vivo, is supposed to be involved in carbonyl/oxidative stress, metabolic disorders, and lifespan shortening of eukaryotes. In this work we aim to expand our understanding of how TOR is involved in carbonyl/oxidative stress caused by reducing monosaccharides. It was found that in fructose-grown compared with glucose-grown cells the level of carbonyl/oxidative stress markers was higher. The defects in the TOR pathway inhibited metabolic rate and suppressed generation of glycoxidation products in fructose-grown yeast.

  8. Rh(I)-catalyzed transformation of propargyl vinyl ethers into (E,Z)-dienals: stereoelectronic role of trans effect in a metal-mediated pericyclic process and a shift from homogeneous to heterogeneous catalysis during a one-pot reaction. (United States)

    Vidhani, Dinesh V; Krafft, Marie E; Alabugin, Igor V


    The combination of experiments and computations reveals unusual features of stereoselective Rh(I)-catalyzed transformation of propargyl vinyl ethers into (E,Z)-dienals. The first step, the conversion of propargyl vinyl ethers into allene aldehydes, proceeds under homogeneous conditions via a "cyclization-mediated" mechanism initiated by Rh(I) coordination at the alkyne. This path agrees well with the small experimental effects of substituents on the carbinol carbon. The key feature revealed by the computational study is the stereoelectronic effect of the ligand arrangement at the catalytic center. The rearrangement barriers significantly decrease due to the greater transfer of electron density from the catalytic metal center to the CO ligand oriented trans to the alkyne. This effect increases electrophilicity of the metal and lowers the calculated barriers by 9.0 kcal/mol. Subsequent evolution of the catalyst leads to the in situ formation of Rh(I) nanoclusters that catalyze stereoselective tautomerization. The intermediacy of heterogeneous catalysis by nanoclusters was confirmed by mercury poisoning, temperature-dependent sigmoidal kinetic curves, and dynamic light scattering. The combination of experiments and computations suggests that the initially formed allene-aldehyde product assists in the transformation of a homogeneous catalyst (or "a cocktail of catalysts") into nanoclusters, which in turn catalyze and control the stereochemistry of subsequent transformations.

  9. A cleavable biotin tagging reagent that enables the enrichment and identification of carbonylation sites in proteins. (United States)

    Coffey, Chelsea M; Gronert, Scott


    The utility of a new, cleavable tag for identifying and enriching protein carbonyls is examined. Using a model system, human serum albumin modified with acrolein, the EZ-Link alkoxyamine-PEG4-SS-PEG4-biotin affinity tag, was tested for its ability to label protein carbonyls in proteomic analyses of protein carbonylation. The efficiency of the labeling was assayed and compared to standard biotin hydrazide reagents. The label was also tested in liquid chromatography-tandem mass spectrometry (LC/MS/MS) experiments. The quality of the fragmentation spectra was assessed and the relative detection efficiency of various modification sites was compared to standard biotin hydrazide reagents. Finally, the viability of using the label with streptavidin bead enrichment protocols in a standard proteomics workflow was probed.

  10. Influence of the Dielectric Medium on the Carbonyl Infrared Absorption Peak of Acetylferrocene

    Directory of Open Access Journals (Sweden)

    F. López-Linares


    Full Text Available The solvent effect on the position of the carbonyl vibrational stretching ofacetylferrocene in aprotic media was studied in this work. The solvent-induced shifts in thisorganometallic compound were interpreted in terms of the alternative reaction field model(SCRF-MO proposed by Kolling. In contrast to the established trends for carbonyl groupsin organic systems, the results suggest that the continuum models for the reaction field arenot adequate and that the influence of dipolarity-polarizability described by aninhomogeneous coupling function θ (ε L(n 2 that assumes optical dielectric saturation isresponsible for the carbonyl band shift and, there is empirical evidence that the effect offield-induced intermolecular interaction on band shift, interpreted in terms of the van derWaals forces from the solvent, have a important contribution to this phenomena.

  11. Influence of carbonyl iron particle coating with silica on the properties of magnetorheological elastomers (United States)

    Małecki, P.; Królewicz, M.; Hiptmair, F.; Krzak, J.; Kaleta, J.; Major, Z.; Pigłowski, J.


    In this paper, the influence of encapsulating carbonyl iron particles with various silica coatings on the properties of magnetorheological elastomers (MREs) was investigated. A soft styrene-ethylene-butylene-styrene thermoplastic elastomer was used as the composite’s polymer matrix. Spherical carbonyl iron powder (CIP) acted as the ferromagnetic filler. In order to improve the metal-polymer interaction, carbonyl iron particles were coated with two types of single and six types of double silica layers. The first layer was created through a TMOS or TEOS hydrolysis whereas the second one was composed of organosilanes. The mechanical properties of MREs containing 38.5 vol% of CIP were analysed under dynamic loading conditions. To investigate the magnetorheological effect in these composites, a 430 mT magnetic field, generated by an array of permanent magnets, was applied during testing. The results revealed that the magnetomechanical response of the MREs differs substantially, depending on the kind of particle coating.

  12. Rhodium-Catalyzed/Copper-Mediated Tandem C(sp(2))-H Alkynylation and Annulation: Synthesis of 11-Acylated Imidazo[1,2-a:3,4-a']dipyridin-5-ium-4-olates from 2H-[1,2'-Bipyridin]-2-ones and Propargyl Alcohols. (United States)

    Li, Ting; Wang, Zhiqiang; Xu, Kun; Liu, Wenmin; Zhang, Xu; Mao, Wutao; Guo, Yongming; Ge, Xiaolin; Pan, Fei


    A rhodium-catalyzed/copper-mediated tandem C(sp(2))-H alkynylation and intramolecular annulation of 2H-[1,2'-bipyridin]-2-ones with propargyl alcohols for the synthesis of 11-acylated imidazo[1,2-a:3,4-a']dipyridin-5-ium-4-olates is described.

  13. Molecular detection and in vitro antioxidant activity of S-allyl-L-cysteine (SAC) extracted from Allium sativum. (United States)

    Sun, Y-E; Wang, W-D


    It is well known that Allium sativum has potential applications to clinical treatment of various cancers due to its remarkable ability in eliminating free radicals and increasing metabolism. An allyl-substituted cysteine derivative - S-allyl-L-cysteine (SAC) was separated and identified from Allium sativum. The extracted SAC was reacted with 1-pyrenemethanol to obtain pyrene-labelled SAC (Py-SAC) to give SAC fluorescence properties. Molecular detection of Py-SAC was conducted by steady-state fluorescence spectroscopy and time-resolved fluorescence method to quantitatively measure concentrations of Py-SAC solutions. The ability of removing 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical using Py-SAC was determined through oxygen radical absorbance capacity (ORAC). Results showed the activity of Py-SAC and Vitamin C (VC) with ORAC as index, the concentrations of Py-SAC and VC were 58.43 mg/L and 5.72 mg/L respectively to scavenge DPPH, and 8.16 mg/L and 1.67 mg/L to scavenge •OH respectively. Compared with VC, the clearance rates of Py-SAC to scavenge DPPH were much higher, Py-SAC could inhibit hydroxyl radical. The ability of removing radical showed a dose-dependent relationship within the scope of the drug concentration.

  14. The - - and Submm-Wave Spectrum of Allyl Isocyanide and Radioastronomical Observations in Orion KL and the Primos Line Survey (United States)

    Haykal, I.; Motiyenko, R. A.; Margules, L.; Huet, T. R.; Ecija, P.; Cocinero, E. J.; Basterretxea, F.; Fernandez, J. A.; Castano, F.; Tercero, B.; Cernicharo, J.; Lesarri, A.; Guillemin, J. C.


    Last year we presented the first rotational analysis of the ground state of the two conformers of allyl isocyanide from 4 GHz to 905 GHz. The analysis of the rotational spectrum of the cis conformer of allyl isocyanide was extended. We resolved Coriolis interactions of a and b types between the excited vibrational states ν_1=1 and ν_2=1, calculated to be at 156 cm^{-1} (A^{'}) and 167 cm^{-1} (A^{''}) respectively (MP2/aug-cc-pvtz), from 150 GHz to 600 GHz. Strong perturbations were observed in the 150-310 GHz range for low values of the quantum number K_a starting from K_a = 0, 1. The anharmonicities appeared as well at higher frequencies for larger quantum numbers. The two modes were fitted together with the SPFIT/SPCAT suite of programs and a set of Coriolis parameters was accurately determined. The fit contains more than 3000 lines up to J = 99 and K_a = 12 for both modes. We did not detect these species neither in the IRAM 30-m line survey of Orion KL nor in the PRIMOS survey towards SgrB2. Nevertheless, we provided upper limits to their column density in Orion KL. This work was supported by the CNES and the Action sur Projets de l'INSU, PCMI. I. Haykal et al. manuscript in preparation H. Pickett J. Mol. Spec.{148}, 371-377, 1991.

  15. Ab initio determination of dark structures in radiationless transitions for aromatic carbonyl compounds. (United States)

    Fang, Wei-Hai


    Mechanistic photodissociation of a polyatomic molecule has long been regarded as an intellectually challenging area of chemical physics, the results of which are relevant to atmospheric chemistry, biological systems, and many application fields. Carbonyl compounds play a unique role in the development of our understanding of the spectroscopy, photochemistry, and photophysics of polyatomic molecules and their photodissociation has been the subject of numerous studies over many decades. Upon irradiation, a molecule can undergo internal conversion (IC) and intersystem crossing (ISC) processes, besides photochemical and other photophysical processes. Transient intermediates formed in the IC and ISC radiationless processes, which are termed "dark", are not amenable to detection by conventional light absorption or emission. However, these dark intermediates play critical roles in IC and ISC processes and thus are essential to understanding mechanistic photochemistry of a polyatomic molecule. We have applied the multiconfiguration complete active space self-consistent field (CASSCF) method to determine the dark transient structures involved in radiationless processes for acetophenone and the related aromatic carbonyl compounds. The electronic and geometric structures predicted for the dark states are in a good agreement with those determined by ultrafast electron diffraction experiments. Intersection structure of different electronic states provides a very efficient "funnel" for the IC or ISC process. However, experimental determination of the intersection structure involved in radiationless transitions of a polyatomic molecule is impossible at present. We have discovered a minimum energy crossing point among the three potential energy surfaces (S1, T1, and T2) that appears to be common to a wide variety of aromatic carbonyl compounds with a constant structure. This new type of crossing point holds the key to understanding much about radiationless processes after

  16. Inhibition of bladder cancer cell proliferation by allyl isothiocyanate (mustard essential oil)

    Energy Technology Data Exchange (ETDEWEB)

    Sávio, André Luiz Ventura, E-mail: [UNESP – Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Departamento de Patologia, Botucatu, SP (Brazil); Nicioli da Silva, Glenda [UFOP – Universidade Federal de Ouro Preto, Escola de Farmácia, Departamento de Análises Clínicas, Ouro Preto, MG (Brazil); Salvadori, Daisy Maria Fávero [UNESP – Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, Departamento de Patologia, Botucatu, SP (Brazil)


    Highlights: • AITC inhibits mutant and wild-type TP53 cell proliferation. • Morphological changes and cells debris were observed after AITC treatment in both cells. • BAX and BCL2 expression modulation was observed in wild-type TP53 cells. • BCL2, BAX and ANLN increased and S100P decreased expression was detected in mutated TP53 cells. • AITC effects in gene modulation are dependent TP53 gene status. - Abstract: Natural compounds hold great promise for combating antibiotic resistance, the failure to control some diseases, the emergence of new diseases and the toxicity of some contemporary medical products. Allyl isothiocyanate (AITC), which is abundant in cruciferous vegetables and mustard seeds and is commonly referred to as mustard essential oil, exhibits promising antineoplastic activity against bladder cancer, although its mechanism of action is not fully understood. Therefore, the aim of this study was to investigate the effects of AITC activity on bladder cancer cell lines carrying a wild type (wt; RT4) or mutated (T24) TP53 gene. Morphological changes, cell cycle kinetics and CDK1, SMAD4, BAX, BCL2, ANLN and S100P gene expression were evaluated. In both cell lines, treatment with AITC inhibited cell proliferation (at 62.5, 72.5, 82.5 and 92.5 μM AITC) and induced morphological changes, including scattered and elongated cells and cellular debris. Gene expression profiles revealed increased S100P and BAX and decreased BCL2 expression in RT4 cells following AITC treatment. T24 cells displayed increased BCL2, BAX and ANLN and decreased S100P expression. No changes in SMAD4 and CDK1 expression were observed in either cell line. In conclusion, AITC inhibits cell proliferation independent of TP53 status. However, the mechanism of action of AITC differed in the two cell lines; in RT4 cells, it mainly acted via the classical BAX/BCL2 pathway, while in T24 cells, AITC modulated the activities of ANLN (related to cytokinesis) and S100P. These data confirm

  17. Is carbonyl sulfide a precursor for carbon disulfide in vegetation and soil? Interconversion of carbonyl sulfide and carbon disulfide in fresh grain tissues in vitro. (United States)

    Ren, Y


    The interconversion of carbonyl sulfide (COS) and carbon disulfide (CS(2)) was studied in the roots and shoots of barley and chickpeas. Ratios of conversion gases, K, 40 h after the addition of COS or CS(2) are recorded. The proportion of COS converted to each of CS(2), CO, and H(2)S and the proportion of CS(2) converted to COS were greater in roots than in shoots. More COS was converted to CS(2) than CS(2) to COS in roots and shoots of barley and chickpeas. The amount of COS converted to H(2)S and CO was 8 times the amount converted to CS(2) in barley and 3-4 times the amount in chickpeas. Carbonyl sulfide may be a precursor for CS(2) in vegetation and soil, just as the reverse is true in the atmosphere. These two different results might form a cycle of COS and CS(2).

  18. Synthesis, characterization of propargyl-cardanol and non-isothermal curing kinetics of its polymer%炔基腰果酚的制备、表征及其聚合物的非等温固化动力学

    Institute of Scientific and Technical Information of China (English)

    吴竞; 史铁钧; 张方; 王启东; 周讯


    Propargyl cardanol was synthesized using cardanol and propargyl bromide by phase transfer catalyst reaction. The chemical structure of propargyl cardanol was characterized by FT-IR, 1H NMR. The results indicated that propargyl cardanol as target compound was obtained through the Williamson ether reaction. Thermal stabilization of poly-propargyl cardanol was evaluated with TG. The initial weight-loss temperature of cured propargyl cardanol was 419℃ and char yield at 800℃ was 14%, which illustrated that the cured propargyl cardano owned well-deserved thermal stability. According to DSC curves, curing kinetic parameters were calculated by two thermo-analysis methods of Kissinger and Flynn-Wall-Ozawa. The respective apparent activation energies were 143.46 and 145.15 kJ·mol-1 respectively and the order of curing reaction both approached to 1, which illustrated that these two kinds of mode were suitable for this system.%以3-溴丙炔、腰果酚为原料,利用相转移催化反应合成了炔基化腰果酚树脂,并用FT-IR、1H NMR对炔基化腰果酚的化学结构进行了表征,结果表明在相转移催化剂存在条件下,3-溴丙炔和腰果酚通过Williamson成醚反应成功制备了目标产物。用TG研究固化后的炔基化腰果酚树脂热稳定性能,结果表明,固化后树脂的起始降解温度为419℃,800℃时的残炭率为14%,说明其具有很好的耐热性能。根据 DSC 曲线,用 Kissinger 和Flynn-Wall-Ozawa分别计算了热固化反应活化能,分别为143.46 kJ·mol-1和145.15 kJ·mol-1,热固化反应级数都接近1,因此说明这两种模式很适合这种体系。

  19. Impaired cardiac SIRT1 activity by carbonyl stress contributes to aging-related ischemic intolerance.

    Directory of Open Access Journals (Sweden)

    Chunhu Gu

    Full Text Available Reactive aldehydes can initiate protein oxidative damage which may contribute to heart senescence. Sirtuin 1 (SIRT1 is considered to be a potential interventional target for I/R injury management in the elderly. We hypothesized that aldehyde mediated carbonyl stress increases susceptibility of aged hearts to ischemia/reperfusion (I/R injury, and elucidate the underlying mechanisms with a focus on SIRT1. Male C57BL/6 young (4-6 mo and aged (22-24 mo mice were subjected to myocardial I/R. Cardiac aldehyde dehydrogenase (ALDH2, SIRT1 activity and protein carbonyls were assessed. Our data revealed that aged heart exhibited increased endogenous aldehyde/carbonyl stress due to impaired ALDH2 activity concomitant with blunted SIRT1 activity (P<0.05. Exogenous toxic aldehydes (4-HNE exposure in isolated cardiomyocyte verified that aldehyde-induced carbonyl modification on SIRT1 impaired SIRT1 activity leading to worse hypoxia/reoxygenation (H/R injury, which could all be rescued by Alda-1 (ALDH2 activator (all P<0.05. However, SIRT1 inhibitor blocked the protective effect of Alda-1 on H/R cardiomyocyte. Interestingly, myocardial I/R leads to higher carbonylation but lower activity of SIRT1 in aged hearts than that seen in young hearts (P<0.05. The application of Alda-1 significantly reduced the carbonylation on SIRT1 and markedly improved the tolerance to in vivo I/R injury in aged hearts, but failed to protect Sirt1(+/- knockout mice against myocardial I/R injury. This was verified by Alda-1 treatment improved postischemic contractile function recovery in ex vivo perfused aged but not in Sirt1(+/- hearts. Thus, aldehyde/carbonyl stress is accelerated in aging heart. These results provide a new insight that impaired cardiac SIRT1 activity by carbonyl stress plays a critical role in the increased susceptibility of aged heart to I/R injury. ALDH2 activation can restore this aging-related myocardial ischemic intolerance.

  20. Ab initio MO study of reaction mechanism for carbonyl migration of Co complex

    Institute of Scientific and Technical Information of China (English)


    Ab initio method under the effective core potential (ECP) approximation is employed to study the reaction mechanism of carbonyl migration of the cycle of olefin hydroformylation catalyzed by a carbonyl cobalt HCo(CO)3 at Hartree-Fock (HF) level. The structures of the reactant, transition state and product for the reaction are determined. The energy of each stationary point is corrected at MP2/LAN2DZ//LANL2DZ+ZPE (zero-point energy) level. The calculated activation barrier is 28.89 kJ/mol.

  1. Formation and emissions of carbonyls during and following gas-phase ozonation of indoor materials

    DEFF Research Database (Denmark)

    Poppendieck, D.G.; Hubbard, H.F.; Weschler, Charles J.;


    from 1 to 20 mg m(-2), with most of the carbonyls being of lower molecular weight (C-1-C-4). In contrast, total BOBP mass released from wood-based products ranged from 20 to 100 mg m(-2), with a greater fraction of the BOBPs being heavier carbonyls (C-5-C-9). The total BOBP mass released during...... relatively high BOBP releases. The greatest overall BOBP mass releases were observed for three materials that building occupants might have significant contact with: paper, office partition, and medium density fiberboard, e.g., often used in office furniture. These materials also exhibited extended BOBP...

  2. Particle growth by acid-catalyzed heterogeneous reactions of organic carbonyls on preexisting aerosols. (United States)

    Jang, Myoseon; Carroll, Brian; Chandramouli, Bharadwaj; Kamens, Richard M


    Aerosol growth by the heterogeneous reactions of different aliphatic and alpha,beta-unsaturated carbonyls in the presence/absence of acidified seed aerosols was studied in a 2 m long flow reactor (2.5 cm i.d.) and a 0.5-m3 Teflon film bag under darkness. For the flow reactor experiments, 2,4-hexadienal, 5-methyl-3-hexen-2-one, 2-cyclohexenone, 3-methyl-2-cyclopentenone, 3-methyl-2-cyclohexenone, and octanal were studied. The carbonyls were selected based on their reactivity for acid-catalyzed reactions, their proton affinity, and their similarity to the ring-opening products from the atmospheric oxidation of aromatics. To facilitate acid-catalyzed heterogeneous hemiacetal/acetal formation, glycerol was injected along with inorganic seed aerosols into the flow reactor system. Carbonyl heterogeneous reactions were accelerated in the presence of acid catalysts (H2SO4), leading to higher aerosol yields than in their absence. Aldehydes were more reactive than ketones for acid-catalyzed reactions. The conjugated functionality also resulted in higher organic aerosol yieldsthan saturated aliphatic carbonyls because conjugation with the olefinic bond increases the basicity of the carbonyl leading to increased stability of the protonated carbonyl. Aerosol population was measured from a series of sampling ports along the length of the flow reactor using a scanning mobility particle sizer. Fourier transform infrared spectrometry of either an impacted liquid aerosol layer or direct reaction of carbonyls as a thin liquid layer on a zinc selenide FTIR disk was employed to demonstrate the direct transformation of chemical functional groups via the acid-catalyzed reactions. These results strongly indicate that atmospheric multifunctional organic carbonyls, which are created by atmospheric photooxidation reactions, can contribute significantly to secondary organic aerosol formation through acid-catalyzed heterogeneous reactions. Exploratory studies in 25- and 190-m3 outdoor chambers

  3. First application of supported ionic liquid phase (SILP) catalysis for continuous methanol carbonylation

    DEFF Research Database (Denmark)

    Riisager, Anders; Jørgensen, Betina; Wasserscheid, Peter


    A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)(2)I-2]-[BMIM]I -SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation.......A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)(2)I-2]-[BMIM]I -SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation....

  4. Photophysical properties of a synthetic, carbonyl-containing (N = 6+Cdbnd O) carotenoid analogue (United States)

    Niedzwiedzki, Dariusz M.


    Retinyl-1 is a synthetic carotenoid analogue belonging to the retinal analogues family. It has six conjugated carbon-carbon double bonds with a carbonyl group conjugated to the π-electron system. Presence of the carbonyl group in vicinity of the conjugated carbon-carbon backbone leads to unique excited state properties that are extremely sensitive to solvent polarity and temperature. The simplicity of the synthesis of Retinyl-1 and ease of attachment to synthetic tetrapyrrole chromophores make Retinyl-1 attractive for use in artificial photosynthetic systems.

  5. Photophysical properties of a synthetic, carbonyl-containing (N=6+CO) carotenoid analogue

    Energy Technology Data Exchange (ETDEWEB)

    Niedzwiedzki, Dariusz M. [Washington Univ., St. Louis, MO (United States)


    Retinyl-1 is a synthetic carotenoid analogue belonging to the retinal analogues family. It has six conjugated carbon–carbon double bonds with a carbonyl group conjugated to the π-electron system. Presence of the carbonyl group in vicinity of the conjugated carbon–carbon backbone leads to unique excited state properties that are extremely sensitive to solvent polarity and temperature. The simplicity of the synthesis of Retinyl-1 and ease of attachment to synthetic tetrapyrrole chromophores make Retinyl-1 attractive for use in artificial photosynthetic systems.


    Institute of Scientific and Technical Information of China (English)

    CHENDean; HUANGShizhuan; 等


    Two kinds of rhodium catalysts supported on cross-linked styrene-divinylbenzene copolymers containing bipyridine or o-phenylene diamine have been prepared and found to display high activity for methyl acetate carbonylation to form acetic anhydride,the activities are even higher than their homogeneous counterparts. XPS analysis was used to characterize the synthetic catalysts.The apparent activation parameters were determined to be Eα=73.3KJ/mol,ΔH≠=66.3KJ/mol,ΔS≠=-28.6eu.These parameters are very close to those in methanol carbonylation and imply to have analogous mechanism in both cases.

  7. Hydrolysis of Carbonyl Sulfide in Binary Mixture of Diethylene Glycol Diethyl Ether and Water

    Institute of Scientific and Technical Information of China (English)

    李新学; 刘迎新; 魏雄辉


    The solubility and hydrolysis of carbonyl sulfide in binary mixture of diethylene glycol diethyl ether and water are studied as a function of composition. The use of an aqueous solution of diethylene glycol diethyl ether enhances the solubility and hydrolysis rate of carbonyl sulfide compared with that in pure water. The composition of the mixture with maximum hydrolysis rate varies with temperature. The thermophysical properties including density, viscosity, and surface tension as a function of composition at 20℃ under atmospheric pressure as well as liquid-liquid equilibrium (LLE) data over the temperature range from 28℃ to 90℃ are also measured for the binary mixture.

  8. Improvement on stability of square planar rhodium (Ⅰ) complexes for carbonylation of methanol to acetic acid

    Institute of Scientific and Technical Information of China (English)

    蒋华; 潘平来; 袁国卿; 陈新滋


    A series of square planar cis-dicarbonyl polymer coordinated rhodium complexes with uncoordinated donors near the central rhodium atoms for carbonylation of methanol to acetic acid are reported. Data of IR, XPS and thermal analysis show that these complexes are very stable. The intramolecular substitution reaction is proposed for their high stability. These complexes show excellent catalytic activity, selectivity and less erosion to the equipment for the methanol carbonylation to acetic acid. The distillation process may be used instead of flash vaporization in the manufacture of acetic acid, which reduces the investment on the equipment.

  9. Chemically activated reactions on the C7H5 energy surface: propargyl + diacetylene, i-C5H3 + acetylene, and n-C5H3 + acetylene. (United States)

    da Silva, Gabriel; Trevitt, Adam J


    This study uses computational chemistry and statistical reaction rate theory to investigate the chemically activated reaction of diacetylene (butadiyne, C(4)H(2)) with the propargyl radical (C˙H(2)CCH) and the reaction of acetylene (C(2)H(2)) with the i-C(5)H(3) (CH(2)CCCC˙H) and n-C(5)H(3) (CHCC˙HCCH) radicals. A detailed G3SX-level C(7)H(5) energy surface demonstrates that the C(3)H(3) + C(4)H(2) and C(5)H(3) + C(2)H(2) addition reactions proceed with moderate barriers, on the order of 10 to 15 kcal mol(-1), and form activated open-chain C(7)H(5) species that can isomerize to the fulvenallenyl radical with the highest barrier still significantly below the entrance channel energy. Higher-energy pathways are available leading to other C(7)H(5) isomers and to a number of C(7)H(4) species + H. Rate constants in the large multiple-well (15) multiple-channel (30) chemically activated system are obtained from a stochastic solution of the one-dimensional master equation, with RRKM theory for microcanonical rate constants. The dominant products of the C(4)H(2) + C(3)H(3) reaction at combustion-relevant temperatures and pressures are i-C(5)H(3) + C(2)H(2) and CH(2)CCHCCCCH + H, along with several quenched C(7)H(5) intermediate species below 1500 K. The major products in the n-C(5)H(3) + C(2)H(2) reaction are i-C(5)H(3) + C(2)H(2) and a number of C(7)H(4) species + H, with C(7)H(5) radical stabilization at lower temperatures. The i-C(5)H(3) + C(2)H(2) reaction predominantly leads to C(7)H(4) + H and to stabilized C(7)H(5) products. The title reactions may play an important role in polycyclic aromatic hydrocarbon (PAH) formation in combustion systems. The C(7)H(5) potential energy surface developed here also provides insight into several other important reacting gas-phase systems relevant to combustion and astrochemistry, including C(2)H + the C(3)H(4) isomers propyne and allene, benzyne + CH, benzene + C((3)P), and C(7)H(5) radical decomposition, for which some

  10. Exciton Coupling in Circular Dichroic Spectroscopy as a Tool for Establishing the Absolute Configuration of alpha,beta-Unsaturated Esters of Allylic Alcohols

    DEFF Research Database (Denmark)

    Lauridsen, A.; Cornett, Claus; Christensen, S. B.


    alpha-beta-Unsaturated esters of allylic alcohols have been shown to exhibit exciton coupling by circular dichroic spectroscopy. This coupling permits the establishment of the absolute configuration. The method was used to prove the absolute configuration at C-2 of archangelolide. Detailed NMR sp...

  11. Nickel-catalyzed enantioselective hydrovinylation of silyl-protected allylic alcohols:An efficient access to homoallylic alcohols with a chiral quaternary center

    Institute of Scientific and Technical Information of China (English)


    Asymmetric hydrovinylation of silyl-protected allylic alcohols catalyzed by nickel complexes of chiral spiro phosphoramidite ligands was developed.A series of homoallylic alcohols with a chiral quaternary center were produced in high yields(up to 97%) and high enantioselectivities(up to 95% ee).The reaction provides an efficient method for preparing bifunctional compounds with a chiral quaternary carbon center.

  12. γ‐ and δ-Lactams through Palladium-Catalyzed Intramolecular Allylic Alkylation: Enantioselective Synthesis, NMR Investigation, and DFT Rationalization

    DEFF Research Database (Denmark)

    Bantreil, Xavier; Prestat, Guillaume; Moreno, Aitor;


    the cyclization reactions to take place in up to 94:6 enantiomeric ratio. A model Pd-allyl complex has been prepared and studied through NMR spectroscopic analysis, which provided insight into the processes responsible for the observed enantiomeric ratios. DFT studies were used to characterize the diastereomeric...

  13. Synthesis of Oxacyclic Scaffolds via Dual Ruthenium Hydride/Brønsted Acid‐Catalyzed Isomerization/Cyclization of Allylic Ethers

    DEFF Research Database (Denmark)

    Ascic, Erhad; Ohm, Ragnhild Gaard; Petersen, Rico;


    A ruthenium hydride/Brønsted acid‐catalyzed tandem sequence is reported for the synthesis of 1,3,4,9‐tetrahydropyrano[3,4‐b]indoles (THPIs) and related oxacyclic scaffolds. The process was designed on the premise that readily available allylic ethers would undergo sequential isomerization, first ...

  14. Photopromoted carbonylation of olefins with carbon dioxide and labelling studies with 13CO2 and 13CH3OH

    Institute of Scientific and Technical Information of China (English)

    YIN Jingmei; GAO Dabin; HU Jiehan; ZHOU Guangyun; JIA Yingping; WANG Xiangsheng


    Photopromoted carbonylation of olefins with carbon dioxide can be completed in ambient conditions (room temperatures and atmospheric pressure) by Co(OAc)2 catalysis. It was found that in carbonyl carbons of methyl ester of aliphatic acid 50% is from CO2 and the other 50% from CH3OH by labelling experimental with 13CO2 and 13CH3OH.

  15. Enhanced antioxidation and electromagnetic properties of Co-coated flaky carbonyl iron particles prepared by electroless plating

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yingying, E-mail: [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Zhou, Wancheng [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Li, Rong [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); No. 603 Faculty, Xi’an Institute of High Technology, Xi’an 710025 (China); Mu, Yang; Qing, Yuchang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China)


    Highlights: • Co-coated carbonyl iron particles were prepared by electroless plating method. • The obvious weight gain of carbonyl iron was deferred to 400 °C after Co-coated. • The permeability of the Co-coated particle composite kept almost invariable. • Co-coated carbonyl iron composite reserves a better absorption after heat treatment. - Abstract: Co was successfully coated on the surface of flaky carbonyl iron particles using an electroless plating method. The morphologies, composition, as well as magnetic, antioxidation and electromagnetic properties of the samples were characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), vibrating sample magnetometer (VSM), thermogravimetric (TG) and microwave network analyzer. TG curve shows that the obvious weight gain of carbonyl iron was deferred from 300 to 400 °C after Co-coated. In contrast to raw carbonyl iron, the Co-coated carbonyl iron shows better stability on electromagnetic properties after 300 °C heat treatment for 10 h, demonstrating that the Co coating can act as the protection of carbonyl iron.

  16. Dormancy alleviation by NO or HCN leading to decline of protein carbonylation levels in apple (Malus domestica Borkh.) embryos. (United States)

    Krasuska, Urszula; Ciacka, Katarzyna; Dębska, Karolina; Bogatek, Renata; Gniazdowska, Agnieszka


    Deep dormancy of apple (Malus domestica Borkh.) embryos can be overcome by short-term pre-treatment with nitric oxide (NO) or hydrogen cyanide (HCN). Dormancy alleviation of embryos modulated by NO or HCN and the first step of germination depend on temporary increased production of reactive oxygen species (ROS). Direct oxidative attack on some amino acid residues or secondary reactions via reactive carbohydrates and lipids can lead to the formation of protein carbonyl derivatives. Protein carbonylation is a widely accepted covalent and irreversible modification resulting in inhibition or alteration of enzyme/protein activities. It also increases the susceptibility of proteins to proteolytic degradation. The aim of this work was to investigate protein carbonylation in germinating apple embryos, the dormancy of which was removed by pre-treatment with NO or HCN donors. It was performed using a quantitative spectrophotometric method, while patterns of carbonylated protein in embryo axes were analyzed by immunochemical techniques. The highest concentration of protein carbonyl groups was observed in dormant embryos. It declined in germinating embryos pre-treated with NO or HCN, suggesting elevated degradation of modified proteins during seedling formation. A decrease in the concentration of carbonylated proteins was accompanied by modification in proteolytic activity in germinating apple embryos. A strict correlation between the level of protein carbonyl groups and cotyledon growth and greening was detected. Moreover, direct in vitro carbonylation of BSA treated with NO or HCN donors was analyzed, showing action of both signaling molecules as protein oxidation agents.

  17. Mitochondrial ATP synthase is a target for TNBS-induced protein carbonylation in XS-106 dendritic cells. (United States)

    Je, Jeong Hwan; Lee, Tae Hyung; Kim, Dong Hyun; Cho, Young Hun; Lee, Ju Hee; Kim, Soo Chan; Lee, Sang-Kyou; Lee, Jaewon; Lee, Min-Geol


    ROS are produced in dendritic cells (DCs) during antigen presentation in contact hypersensitivity (CHS). As a result, ROS cause a number of nonenzymatic protein modifications, including carbonylation, which is the most widely used marker of oxidative stress. 2,4,6-Trinitrobenzene sulfonic acid (TNBS) is a well-characterized contact allergen that results in the formation of ROS. However, proteins that are carbonylated in DCs in response to TNBS have not been identified. To study ROS-dependent protein carbonylation in response to TNBS, we used the well-established mouse DC line, XS-106. We focused on the effects of TNBS on oxidation by examining selected oxidative markers. We identified TNBS-induced ROS and myeloperoxidase (MPO) proteins and demonstrated that the increase in ROS resulted in IL-12 production. The increase in oxidation was further confirmed by an oxidation-dependent increase in protein modifications, such as carbonylation. In fact, TNBS strongly induced carbonylation of mitochondrial adenosine triphosphate (ATP) synthase in XS-106 DCs, as determined by MALDI-TOF analysis and 2-D Western blotting. ROS production and protein carbonylation were confirmed in human monocyte-derived DCs (Mo-DCs). Furthermore, glutathione (GSH) decreased ROS and protein carbonylation in Mo-DCs. Carbonylation of ATP synthase in DCs may contribute to the pathophysiology of CHS.

  18. Regiospecific oxidation of an alkyl group of aromatic amine to carbonyl group by DDQ in aq.medium

    Institute of Scientific and Technical Information of China (English)

    Madhav S. Mane; Ravi S. Balaskar; Sandip N. Gavade; Pramod N. Pabrekar; Murlidhar S. Shingare; Dhananjay V. Mane


    The regiospecific oxidation of alkyl group of both sterically hindered and unhindered aromatic amine to corresponding carbonyl compound was done in aq. medium by using DDQ. The optimized reaction protocol was found to be most simple, high yielding and novel method for oxidation of alkyl group of aromatic amine in to its carbonyl compound.

  19. Synthesis of the [beta]-D-glucosyl ester of [carbonyl-[sup 13]C]-indole-3-acetic acid

    Energy Technology Data Exchange (ETDEWEB)

    Jakas, A.; Magnus, V. (Rudjer Boskovic Inst., Zagreb (Croatia)); Horvat, S.; Sandberg, G. (Swedish Univ. of Agricultural Sciences, Uppsala (Sweden))


    An efficient, operationally simple synthetic approach to 1-O-([carbonyl-[sup 13]C]-indole-3'-ylacetyl)-[beta]-D-glucopyranose is described. The synthesis was carried out by fusing a fully benzylated 1-O-glucosylpseudourea intermediate with [carbonyl-[sup 13]C]-indole-3-acetic acid, followed by hydrogenolytic removal of the protective groups. (Author).

  20. Efficient preparation of carbamates by Rh-catalysed oxidative carbonylation: unveiling the role of the oxidant. (United States)

    Iturmendi, Amaia; Iglesias, Manuel; Munárriz, Julen; Polo, Victor; Pérez-Torrente, Jesús J; Oro, Luis A


    The synthesis of a wide variety of carbamates from amines, alcohols and carbon monoxide has been achieved by means of a Rh-catalysed oxidative carbonylation reaction that uses Oxone as a stoichiometric oxidant. In-depth studies on the reaction mechanism shed light on the intimate role of Oxone in the catalytic cycle.

  1. Weak carbonyl-methyl intermolecular interactions in acetone clusters explored by IR plus VUV spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Jiwen [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Hu, Yongjun, E-mail: [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Xie, Min [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Bernstein, Elliot R. [Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872 (United States)


    Highlights: Black-Right-Pointing-Pointer The carbonyl overtone of acetone clusters is observed by IR-VUV spectroscopy. Black-Right-Pointing-Pointer Acetone molecules in the dimer are stacked with an antiparallel way. Black-Right-Pointing-Pointer The structure of the acetone trimer and the tetramer are the cyclic structures. Black-Right-Pointing-Pointer The carbonyl groups would interact with the methyl groups in acetone clusters. Black-Right-Pointing-Pointer These weak interactions are further confirmed by H/D substitution experiment. -- Abstract: Size-selected IR-VUV spectroscopy is employed to detect vibrational characteristics in the region 2850 {approx} 3550 cm{sup -1} of neutral acetone and its clusters (CH{sub 3}COCH{sub 3}){sub n} (n = 1-4). Features around 3440 cm{sup -1} in the spectra of acetone monomer and its clusters are assigned to the carbonyl stretch (CO) overtone. These features red-shift from 3455 to 3433 cm{sup -1} as the size of the clusters increases from the monomer to the tetramer. Based on calculations, the experimental IR spectra in the C=O overtone region suggest that the dominant structures for the acetone trimer and tetramer should be cyclic in the supersonic expansion sample. This study also suggests that the carbonyl groups interact with the methyl groups in the acetone clusters. These weak interactions are further confirmed by the use of deuterium substitution.

  2. Palladium-Catalyzed Carbonylation of Primary Amines in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    李金恒; 江焕峰; 陈鸣才


    The chemoselectity of the palladimm-catalyzed carbonylation of amines was affected by the addition of MeOH in supercritical carbon dioxide. The results show different selectivity in supercritical carbon dioxide CO2(sc) from that in alcohol.Methyl carbamate and its derivatives were obtained in high yields in CO2(sc).

  3. N-Heterocyclic Carbene-Palladium Complex Catalyzed Oxidative Carbonylation of Amines to Ureas

    Institute of Scientific and Technical Information of China (English)

    ZHENG,Shu-Zhan; PENG,Xin-Gao; LIU,Jian-Ming; SUN,Wei; XIA,Chun-Gu


    Palladium carbene shows high efficiency without any promoter on oxidative carbonylation of amines to ureas and a new type of palladium carbene complex containing both an aniline and an NHC ligands was found to be the active species for the reaction.

  4. Magnetic Silica-Supported Ruthenium Nanoparticles: An Efficient Catalyst for Transfer Hydrogenation of Carbonyl Compounds (United States)

    One-pot synthesis of ruthenium nanoparticles on magnetic silica is described which involve the in situ generation of magnetic silica (Fe3O4@ SiO2) and ruthenium nano particles immobilization; the hydration of nitriles and transfer hydrogenation of carbonyl compounds occurs in hi...

  5. The carbonylation of phenyl bromide and its derivatives under visible light irradiation

    Institute of Scientific and Technical Information of China (English)

    Wen Hui Zhong; Ying Na Cui; Shen Min Li; Ying Ping Jia; Jing Mei Yin


    The carbonylation of phenyl bromide catalyzed by Co(OAc)2 has been investigated with PhCOPh as a sensitizer under visible light in the presence of basic additive.With strong base CH3ONa,PhCOOCH3 is produced in 70% yield with 100% selectivity,the similar results are also obtained with a stronger base (CH3)3CONa.However,with another strong base NaOH,the yield of the ester is only 40%.On the other hand,with weak base NaOAc or (n-C4Hg)3N,phenyl bromide cannot be carbonylated.The results of carbonylation of the six substituted phenyl bromides suggest that the activities of o,m,p-BrC6H4CH3 are similar to phenyl bromide,while the activities of o,m,p-BrC6H4Cl are higher with the high yields (≥93%) of the corresponding chloro-esters.In addition,the relative position of bromine and chlorine or methyl on phenyl ring has little effect on the activity of the carbonylation.

  6. α-Carbonyl Radical Cyclization for the Total Synthesis of Natural Products

    Institute of Scientific and Technical Information of China (English)

    SHA Chin-Kang; CHIU Rei-Torng; LIH Shinn-Horng; SANTHOSH K. C.; CHANG Ching-Jung; TSENG Wei-Hong; HO Wen-Yueh


    @@ Intramolecular radical cyclization reactions are now used routinely to synthesize carbocyclic and heterocyclicstructures. We have reported that α-carbonyl radicals 1, generated from the corresponding iodo ketones or enones,underwent intramolecular radical cyclization smoothly to afford products 2. [1,2

  7. Oxalyl chloride as a practical carbon monoxide source for carbonylation reactions

    DEFF Research Database (Denmark)

    Hansen, Steffen V F; Ulven, Trond


    A method for generation of high-quality carbon monoxide by decomposition of oxalyl chloride in an aqueous hydroxide solution is described. The usefulness of the method is demonstrated in the synthesis of heterocycles and for hydroxy-, alkoxy-, amino-, and reductive carbonylation reactions, in sev...

  8. Ketene as a Reaction Intermediate in the Carbonylation of Dimethyl Ether to Methyl Acetate over Mordenite

    DEFF Research Database (Denmark)

    Rasmussen, Dominik Bjørn; Christensen, Jakob Munkholt; Temel, Burcin


    Unprecedented insight into the carbonylation of dimethyl ether over Mordenite is provided through the identification of ketene (CH2CO) as a reaction intermediate. The formation of ketene is predicted by detailed DFT calculations and verified experimentally by the observation of doubly deuterated ...

  9. Peculiar features of composition of carbonyl components of surface lipids in aquatic plants


    І. О. Alexeevs’ka; V. M. Shepelenko; N. I. Shtemenko


    Carbonyl components content of aquatic plants’ surface lipids has been studied. High concentration of oxo-compounds in surface lipids of aquatic plants has been shown. It could reach 60 % of total value. Sufficient heterogeneity of surface lipids has been demonstrated. Unsaturated character of oxo-components in aquatic plants’ surface lipids has been assumed in the present work.

  10. Determination of protein carbonyls in plasma, cell extracts, tissue homogenates, isolated proteins

    DEFF Research Database (Denmark)

    Weber, Daniela; Davies, Michael J.; Grune, Tilman


    Protein oxidation is involved in regulatory physiological events as well as in damage to tissues and is thought to play a key role in the pathophysiology of diseases and in the aging process. Protein-bound carbonyls represent a marker of global protein oxidation, as they are generated by multiple...

  11. Preparation and characterization of carbonyl iron/glass composite absorber as matched load for isolator (United States)

    Feng, Yongbao; Li, Yujiao; Qiu, Tai


    Composite absorbers made from 66 wt% carbonyl iron and 34 wt% low melting point glass powder were prepared by a pressureless sintering technique in a nitrogen atmosphere. Apparent porosity and bending strength of the as-prepared composites were investigated. The microstructure, heat resisting properties and electromagnetic properties were characterized by scanning electron microscopy, thermal gravimetric analysis-differential scanning calorimetry and vector network analyzer. The results show that the carbonyl iron/glass composite absorbers were difficult to densify. As the sintering temperature and soaking time increased, the apparent porosity first decreased and then increased, whereas the bending strength showed the opposite change. The composite absorber sintered at 520 °C for 40 min achieved the minimum apparent porosity of 13.08% and the highest bending strength of 52 MPa. Compared to the carbonyl iron/silicone rubber absorber, the carbonyl iron/glass composite absorber exhibited better heat resisting properties, and the initial oxidation temperature was increased about 200 °C. The composite absorber with a thickness of 1.25 mm showed a good microwave absorbing property in 8-12 GHz.

  12. Proteomic and carbonylation profile analysis of rat skeletal muscles following acute swimming exercise.

    Directory of Open Access Journals (Sweden)

    Francesca Magherini

    Full Text Available Previous studies by us and other groups characterized protein expression variation following long-term moderate training, whereas the effects of single bursts of exercise are less known. Making use of a proteomic approach, we investigated the effects of acute swimming exercise (ASE on protein expression and carbonylation patterns in two hind limb muscles: the Extensor Digitorum Longus (EDL and the Soleus, mostly composed of fast-twitch and slow-twitch fibres, respectively. Carbonylation is one of the most common oxidative modifications of proteins and a marker of oxidative stress. In fact, several studies suggest that physical activity and the consequent increase in oxygen consumption can lead to increase in reactive oxygen and nitrogen species (RONS production, hence the interest in examining the impact of RONS on skeletal muscle proteins following ASE. Results indicate that protein expression is unaffected by ASE in both muscle types. Unexpectedly, the protein carbonylation level was reduced following ASE. In particular, the analysis found 31 and 5 spots, in Soleus and EDL muscles respectively, whose carbonylation is reduced after ASE. Lipid peroxidation levels in Soleus were markedly reduced as well. Most of the decarbonylated proteins are involved either in the regulation of muscle contractions or in the regulation of energy metabolism. A number of hypotheses may be advanced to account for such results, which will be addressed in future studies.

  13. Inactivation of cellular enzymes by carbonyls and protein-bound glycation/glycoxidation products

    DEFF Research Database (Denmark)

    Morgan, Philip E; Dean, Roger T; Davies, Michael Jonathan


    Diabetic plasma contains elevated levels of glucose and various low-molecular-weight carbonyl compounds derived from the metabolism of glucose and related materials. These compounds react with protein side chains (Arg, Lys, Cys, and His) to give glycated materials and advanced glycation end produ...

  14. Reductive Deoxygenation of Carbonyl to Methylene by LiAlH4/InBr3

    Institute of Scientific and Technical Information of China (English)

    Nan Yan FU; Xue Mei ZHAO; Yao Feng YUAN; Ji Tao WANG


    The reductive deoxygenation of aldehydes and ketones into the corresponding alkanes isaccomplished by LiA1H4 in the presence of Lewis acid InBr3. It provides a convenient method tocomplete the transformation from carbonyl compounds to alkanes.

  15. Synthesis, spectroscopic characterizations, crystal structures and DFT studies of nalidixic acid carbonyl hydrazones derivatives (United States)

    Bergamini, F. R. G.; Ribeiro, M. A.; Lancellotti, M.; Machado, D.; Miranda, P. C. M. L.; Cuin, A.; Formiga, A. L. B.; Corbi, P. P.


    This article describes the synthesis and characterization of the 1-ethyl-7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carbohydrazide (hzd) and six carbonyl hydrazones derivatives of the nalidixic with 1H-pyrrol-2-ylmethylidene (hpyrr), 1H-imidazol-2-ylmethylidene (h2imi), pyridin-2-ylmethylidene (h2py), pyridin-3-ylmethylidene (h3py), pyridin-4-ylmethylidene(h4py) and (2-hydroxyphenyl)methylidene (hsali). The carbonyl hydrazones were characterized by elemental and ESI-QTOF-MS analyses, IR and detailed NMR spectroscopic measurements. The 2D NMR experiments allowed the unambiguous assignment of the hydrogen, carbon and nitrogen atoms, which have not been reported for nalidixic acid carbonyl hydrazone derivatives so far. Crystal structures of hzd and the new carbonyl hydrazones h2imi, hpyrr and h3py were determined by X-ray diffraction studies. Although the synthesis of hzd was reported decades ago, the hzd crystal structure have not been reported yet. Geometric optimizations of all the characterized structures were performed with the aid of DFT studies. Despite the fact that the hydrazones with 2-pyridine carboxylic acid (h2py) and salicyl aldehyde (hsali) were already reported by literature, a detailed spectroscopic study followed by DFT studies are also reported for such compounds in this manuscript. Antimicrobial studies of the compounds are also presented.

  16. Levels, sources and health risks of carbonyls and BTEX in the ambient air of Beijing, China

    Institute of Scientific and Technical Information of China (English)

    Yujie Zhang; Yujing Mu; Junfeng Liu; Abdelwahid Mellouki


    The atmospheric concentrations of carbonyls and BTEX (benzene,toluene,ethylbenzene,m,p-xylene and o-xylene) were measured simultaneously at a same sampling site in Beijing from September 2008 to August 2010.The average concentrations of the total measured carbonyls during autumn,winter,spring,and summer were 37.7,31.3,39.7,50.5 μg/m3,respectively,and maximal values for their diurnal variations usually happened at noontime.In contrast to carbonyls,the average concentrations of the total measured BTEX during the four seasons were 27.2,31.9,23.2,19.1 μg/m3,respectively,and minimal values for their diurnal variations always occurred in the early afternoon.The average concentration for carbonyls increased about 24% from September 2008-August 2009 to September 2009-August 2010,for BTEX,increased about 15%.Integrated life time cancer risks for three carcinogens (benzene,formaldehyde and acetaldehyde) in Beijing exceeded the value of 1E-06,and the hazard quotient (HQ) of non-cancer risk of exposure to formaldehyde exceeded unity.

  17. The Solvent Mixture Sensitivity of Carbonyl Stretching Frequencies of 2-Pyrrolidinones and Related Compounds

    NARCIS (Netherlands)

    Perjessy, A.; Engberts, J.B.F.N.; Blandamer, M.J.


    The carbonyl stretching frequencies of 1-substituted 2-pyrrolidinones and related compounds were measured in binary mixtures of hexane-CDCl3 and acetonitrile-D2O and plotted against the mole fraction of the less polar co-solvent The v(C=O) vs. mole fraction correlations enabled to recognize and assi

  18. Direct photolysis of carbonyl compounds dissolved in cloud and fog~droplets (United States)

    Epstein, S. A.; Tapavicza, E.; Furche, F.; Nizkorodov, S. A.


    Gas-phase photolysis is an important tropospheric sink for many carbonyl compounds; however the significance of direct photolysis of these compounds dissolved in cloud and fog droplets is uncertain. We develop a theoretical approach to assess the importance of aqueous photolysis for a series of carbonyls that possess carboxyl and hydroxyl functional groups by comparison with rates of other atmospheric processes. We use computationally and experimentally derived effective Henry's law constants, hydration equilibrium parameters, aqueous hydroxyl radical (OH) rate constants, and optical extinction coefficients to identify types of compounds that will (or will not) have competitive aqueous photolysis rates. We also present molecular dynamics simulations designed to estimate gas- and aqueous-phase extinction coefficients of unstudied atmospherically relevant compounds found in d-limonene and isoprene secondary organic aerosol. In addition, experiments designed to measure the photolysis rate of glyceraldehyde, an atmospherically relevant water-soluble organic compound, reveal that aqueous quantum yields are highly molecule-specific and cannot be extrapolated from measurements of structurally similar compounds. We find that only two out of the 92 carbonyl compounds investigated, pyruvic acid and acetoacetic acid, may have aqueous photolysis rates that exceed the rate of oxidation by dissolved OH. For almost all carbonyl compounds lacking α,β-conjugation that were investigated, atmospheric removal by direct photolysis in cloud and fog droplets can be neglected under typical atmospheric conditions.

  19. Study on the Carbonyl Iron Powder Based Nano-Composite Radar Wave Absorbing Coatings

    Institute of Scientific and Technical Information of China (English)

    HUANG Dong-zhen; WANG Zhi-hui; LV Yan-hong; HU Chuan-xin; LI Wan-zhi; LIANG wen-ting; YAO Jun-min


    With the rapid development of stealth technique, carbonyl iron powder is regarded as an ideal radar absorbing material. In this paper, radar absorbing properties of carbonyl iron powder was investigated by using nano composite and macroscopic multi- layer composite approach. The machine- chemistry composite methods were employed during the experiment to produce nano composite absorbent. Two carbonyl iron powders named HP1, HP2 and nano powder named HP3 were employed. Absorbents were obtained by adding 10% HP3 powder with average size of 28 nm to the HP1 and HP2 carbonyl iron powders by weight respectively. By a series of composite techniques, sample plate with the radar absorbing coating was prepared. Compared with the single coating, the wave absorbing properties were significantly improved. The working band in which the wave reflectivity was less than 5 db was 4.8 ~ 18 GHz with the coating thickness of 1.0 mm. The lowest reflectivity was found to be 12.34 db at 8 GHz. The wave absorbing coating with thin thickness,broadband and strong absorbing properties was obtained.

  20. Chemo- and Stereoselective Reduction of Polyfunctional Carbonyl Compounds by Mucor rouxii

    Directory of Open Access Journals (Sweden)

    Constanza P. Mangone


    Full Text Available Several polyfunctional carbonyl compounds, such as α- and β-ketoesters, were chemo- and stereoselectively reduced by Mucor rouxii cultures in water and in organic solvents. Results show that reductions can be carried out in a variety of organic solvents.


    An automatic gas chromatograph with a flame photometric detector that samples and analyzes hydrogen sulfide and carbonyl sulfide at 30-s intervals is described. Temperature programming was used to elute trace amounts of carbon disulfide present in each injection from a Supelpak-S...

  2. NMR Studies of Structure-Reactivity Relationships in Carbonyl Reduction: A Collaborative Advanced Laboratory Experiment (United States)

    Marincean, Simona; Smith, Sheila R.; Fritz, Michael; Lee, Byung Joo; Rizk, Zeinab


    An upper-division laboratory project has been developed as a collaborative investigation of a reaction routinely taught in organic chemistry courses: the reduction of carbonyl compounds by borohydride reagents. Determination of several trends regarding structure-activity relationship was possible because each student contributed his or her results…

  3. Hydration and hydrogen bonding of carbonyls in dimyristoyl-phosphatidylcholine bilayer. (United States)

    Volkov, Victor V; Nuti, Francesca; Takaoka, Yuji; Chelli, Riccardo; Papini, Anna Maria; Righini, Roberto


    We combine two-color ultrafast infrared spectroscopy and molecular dynamics simulation to investigate the hydration of carbonyl moieties in a dimyristoyl-phosphatidylcholine bilayer. Excitation with femtosecond infrared pulses of the OD stretching mode of heavy water produces a time dependent change of the absorption band of the phospholipid carbonyl groups. This intermolecular vibrational coupling affects the entire C=O band, thus suggesting that the optical inhomogeneity of the infrared response of carbonyl in phospholipid membranes cannot be attributed to the variance in hydration. Both the experimental and the theoretical results demonstrate that sn-1 carbonyl has a higher propensity to form hydrogen bonds with water in comparison to sn-2. The time-resolved experiment allows following the evolution of the system from a nonequilibrium localization of energy in the OD stretching mode to a thermally equilibrated condition and provides the characteristic time constants of the process. The approach opens a new opportunity for investigation of intermolecular structural relations in complex systems, like membranes, polymers, proteins, and glasses.

  4. Ketene as a Reaction Intermediate in the Carbonylation of Dimethyl Ether to Methyl Acetate over Mordenite

    DEFF Research Database (Denmark)

    Rasmussen, Dominik Bjørn; Christensen, Jakob Munkholt; Temel, Burcin;


    Unprecedented insight into the carbonylation of dimethyl ether over Mordenite is provided through the identification of ketene (CH2CO) as a reaction intermediate. The formation of ketene is predicted by detailed DFT calculations and verified experimentally by the observation of doubly deuterated...

  5. [pi] Backbonding in Carbonyl Complexes and Carbon-Oxygen Stretching Frequencies: A Molecular Modeling Exercise (United States)

    Montgomery, Craig D.


    An exercise is described that has illustrated the effect of various factors on [pi] backbonding to carbonyl ligands, where the students can view the molecular orbitals corresponding to the M-CO [pi] interaction as well as the competing interaction between the metal and co-ligands. The visual and hands-on nature of the modeling exercise has helped…

  6. Towards a General Understanding of Carbonyl-Stabilised Ammonium Ylide-Mediated Epoxidation Reactions. (United States)

    Novacek, Johanna; Roiser, Lukas; Zielke, Katharina; Robiette, Raphaël; Waser, Mario


    The key factors for carbonyl-stabilised ammonium ylide-mediated epoxidation reactions were systematically investigated by experimental and computational means and the hereby obtained energy profiles provide explanations for the observed experimental results. In addition, we were able to identify the first tertiary amine-based chiral auxiliary that allows for high enantioselectivities and high yields for such epoxidation reactions.

  7. Modular Approach for Novel Nanostructered Polycondensates Enabled by the Unique Selectivity of Carbonyl Biscaprolactam

    NARCIS (Netherlands)

    Loontjens, Ton


    New enabling chemistries have been developed to produce novel well-defined polymeric materials through the additions of small amounts of reactive functional compounds to standard polymers during regular processing steps. We found that carbonyl biscaprolactam and its derivatives couple polymer chains

  8. Ab initio study on the mechanism of rhodium-complexcatalyzed carbonylation of methanol to acetic acid

    Institute of Scientific and Technical Information of China (English)

    LEI; Ming


    [1]Thomas, R., Cundari, T. R., Computational studies of transition metal-main group multiple bonding, Chem. Rev., 2000,100: 807.[2]Maricel Torrent, Miquel Sola, Gernot Frenking, Theoretical studies of some transition-metal-mediated reactions of industrial and synthetic importance, Chem. Rev., 2000, 100: 439.[3]Paulik, F. E., Roth, J. F., Catalysts for the low-pressure carbonylation of menthanol to acetic acid, Chem. Commun., 1968,24: 1578.[4]Jiang Hua, Diao Kaisheng, Pan Pinglai et al., A new class of rhodium complexes containing free donor atoms and their intramolecular substitution reaction, Chin. J. Chem., 2000, 18: 752.[5]Jiang Dazhi, Li Xiaobao, Wang Enlai, Synthesis Chemistry ofCarbonylation, Beijing: Chemical Technology Press, 1996.[6]Adamson, G. W., Daly, J. J., Forster, D., Reduction of iolocarbonyl rhodium ions with methyl iodide, structure of the rho-dium acetyl complex: [Me3PhN+], [Rh2I6-(Me(O)2(CO)2)]2-, J. Organomet. Chem., 1974, 71: C 17.[7]Forster, D., On the mechanism of a rhodium-complex-catalyzed carbonylation of methanol to acetic acid, J. Am. Chem.Soc., 1976, 98: 846.[8]Hjortkjaer, J., Jensen, O. R., Rhodium complexes catalyzed methanol carbonylation, Ind. Eng. Chem. Prod. Dev., 1976, 15:46.[9]Jeffrey, P., Wadt, W. R., Ab initio effective core potentials for molecular calculations, Potentials for the transition metalatoms Sc to Hg, J. Chem. Phys., 1995, 82: 270.[10]Frisch, M. J., Trunks, G. W., Schlegel, H. B. et al., Gaussian 94, Pittsburgh PA: Gaussian, Inc., 1995.[11]Lei Ming, Feng Wenlin, Xu Zhenfeng et al., A theoretical study on the key reactions of hydroformylation cycle by modi-fied carbonyl cobalt, Chemical Journal of Chinese University, 2001, 22: 455.[12]Lei Ming, Feng Wenlin, Xu Zhenfeng, Ab initio MO study on the reaction mechanism for carbonyl insertion catalyzed by the carbonyl cobalt complex, Chemical Research in Chinese University, 2000, 19:31.

  9. Proteomic identification of carbonylated proteins in F344 rat hippocampus after 1-bromopropane exposure. (United States)

    Huang, Zhenlie; Ichihara, Sahoko; Oikawa, Shinji; Chang, Jie; Zhang, Lingyi; Subramanian, Kaviarasan; Mohideen, Sahabudeen Sheik; Ichihara, Gaku


    1-Bromopropane (1-BP) is neurotoxic in both experimental animals and humans. Previous proteomic analysis of rat hippocampus implicated alteration of protein expression in oxidative stress, suggesting that oxidative stress plays a role in 1-BP-induced neurotoxicity. To understand this role at the protein level, we exposed male F344 rats to 1-BP at 0, 400, or 1000 ppm for 8h/day for 1 week or 4 weeks by inhalation and quantitated changes in hippocampal protein carbonyl using a protein carbonyl assay, two-dimensional gel electrophoresis (2-DE), immunoblotting, and matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF-TOF/MS). Hippocampal reactive oxygen species and protein carbonyl were significantly increased, demonstrating 1-BP-associated induction of oxidative stress and protein damage. MALDI-TOF-TOF/MS identified 10 individual proteins with increased carbonyl modification (p < 0.05; fold-change ≥ 1.5). The identified proteins were involved in diverse biological processes including glycolysis, ATP production, tyrosine catabolism, GTP binding, guanine degradation, and neuronal metabolism of dopamine. Hippocampal triosephosphate isomerase (TPI) activity was significantly reduced and negatively correlated with TPI carbonylation (p < 0.001; r = 0.83). Advanced glycation end-product (AGE) levels were significantly elevated both in the hippocampus and plasma, and hippocampal AGEs correlated negatively with TPI activity (p < 0.001; r = 0.71). In conclusion, 1-BP-induced neurotoxicity in the rat hippocampus seems to involve oxidative damage of cellular proteins, decreased TPI activity, and elevated AGEs.

  10. Spatial distributions of airborne di-carbonyls in urban and rural areas in China (United States)

    Lui, K. H.; Dai, Wen-Ting; Chan, C. S.; Ho, Steven Sai Hang; Cao, Jun-Ji; Lee, S. C.; Ho, K. F.


    Gaseous glyoxal and methylglyoxal concentrations were characterized in nine cities of China during 2010-2011. The average summer (winter) glyoxal and methylglyoxal concentrations were 36.4-178.4 (12.3-241.4) and 67.8-359.4 (28.4-530.0) ng/m3, respectively. In summer, the highest average glyoxal concentration was in Guangzhou (GZ), while the lowest was in Shanghai (SH). In winter, Xiamen (XM) showed the highest average methylglyoxal concentration and Yantai (YT) reported the lowest. Both di-carbonyls showed distinct seasonal variations. The maximum average methylglyoxal concentration was approximately twice as much as glyoxal, which is consistent with the results of other studies. Glyoxal-to-methylglyoxal ratios showed that there was a consistent direct source of emissions in remote areas such as Qinghai Lake and Lhasa in both seasons (r ≥ 0.9). Pearson's correlation analysis suggested possible similar sources formation (R ≥ 0.7) for the two di-carbonyls in winter. Multiple linear regression analyses demonstrated that every 1 °C temperature increase could lead to a > 2% increase in the concentration of the di-carbonyls in both seasons. There was a greater percentage gain for glyoxal in winter than in summer for the same temperature increase. The northeast monsoon occurs in winter, and for every 1 ms- 1 increase in wind speed, > 20% of the di-carbonyls can be transferred out of China. This study is useful to understand about the secondary organic aerosol formation in the areas, the statistical analysis can provide information about the relationships between these carbonyls in atmosphere.

  11. Improved synthesis of cyclic tertiary allylic alcohols by asymmetric 1,2-addition of AlMe3 to enones. (United States)

    Kolb, Andreas; Zuo, Wei; Siewert, Jürgen; Harms, Klaus; von Zezschwitz, Paultheo


    The development of an improved protocol for the enantioselective Rh(I) /binap-catalysed 1,2-addition of AlMe3 to cyclic enones is reported. (31)P NMR analysis of the reaction revealed that the catalyst in its resting state is a chloride-bridged dimer. This insight led to the use of AgBF4 as an additive for in situ activation of the dimeric precatalyst. Thus, the catalyst loading can now be reduced to only 1 mol% with respect to rhodium. Various 5-7-membered cyclic enones can be transformed into tertiary allylic alcohols with excellent levels of enantioselectivity and high yields. The obtained products are versatile synthetic building blocks, shown by a highly enantioselective formal total synthesis of the pheromone (-)-frontalin as well as formation of a bicyclic lactone that has the core structure of the natural flavour component "wine lactone".

  12. Practical and Broadly Applicable Catalytic Enantioselective Additions of Allyl-B(pin) Compounds to Ketones and α-Ketoesters. (United States)

    Robbins, Daniel W; Lee, KyungA; Silverio, Daniel L; Volkov, Alexey; Torker, Sebastian; Hoveyda, Amir H


    A set of broadly applicable methods for efficient catalytic additions of easy-to-handle allyl-B(pin) (pin=pinacolato) compounds to ketones and acyclic α-ketoesters was developed. Accordingly, a large array of tertiary alcohols can be obtained in 60 to >98 % yield and up to 99:1 enantiomeric ratio. At the heart of this development is rational alteration of the structures of the small-molecule aminophenol-based catalysts. Notably, with ketones, increasing the size of a catalyst moiety (tBu to SiPh3 ) results in much higher enantioselectivity. With α-ketoesters, on the other hand, not only does the opposite hold true, since Me substitution leads to substantially higher enantioselectivity, but the sense of the selectivity is reversed as well.

  13. Isolation and recovery of cellulose from waste nylon/cotton blended fabrics by 1-allyl-3-methylimidazolium chloride. (United States)

    Lv, Fangbing; Wang, Chaoxia; Zhu, Ping; Zhang, Chuanjie


    Development of a simple process for separating cellulose and nylon 6 from their blended fabrics is indispensable for recycling of waste mixed fabrics. An efficient procedure of dissolution of the fabrics in an ionic liquid 1-allyl-3-methylimidazolium chloride ([AMIM]Cl) and subsequent filtration separation has been demonstrated. Effects of treatment temperature, time and waste fabrics ratio on the recovery rates were investigated. SEM images showed that the cotton cellulose dissolved in [AMIM]Cl while the nylon 6 fibers remained. The FTIR spectrum of regenerated cellulose (RC) was similar with that of virgin cotton fibers, which verified that no other chemical reaction occurred besides breakage of hydrogen bonds during the processes of dissolution and separation. TGA curves indicated that the regenerated cellulose possessed a reduced thermal stability and was effectively removed from waste nylon/cotton blended fabrics (WNCFs). WNCFs were sufficiently reclaimed with high recovery rate of both regenerated cellulose films and nylon 6 fibers.

  14. Synthesis, spectroscopic characterization and solution behavior of new tin tetrachloride adducts with γ-keto allyl phosphonates (United States)

    Elleuch, Haitham; Sanhoury, M. A. K.; Rezgui, F.


    Four new octahedral complexes of the type [SnCl4L2] (L = γ-keto allyl phosphonate) (1-4) were prepared and characterized by multinuclear (1H, 13C, 31P and 119Sn) NMR, IR spectroscopy and elemental analysis. The NMR data show, as expected, that these complexes exist in solution as mixtures of cis and trans isomers. More importantly, the solution structure was confirmed by 119Sn NMR spectra which show two triplets corresponding to the two isomers. In addition, the solution behavior of these complexes in the presence of excess ligand was studied by variable temperature NMR using the coalescence temperature method. The metal-ligand exchange activation energies were therefore determined and found to be in the range 57-60 kJ/mol. The effect of remote substituents on the metal-ligand interaction was studied and compared with closely related tin-phosphoryl complexes.

  15. Crystal structure of (E-4-(acetoxyimino-N-allyl-3-isopropyl-2,6-diphenylpiperidine-1-carbothioamide

    Directory of Open Access Journals (Sweden)

    T. Mohandas


    Full Text Available The title compound, C26H31N3O2S, crystallizes with two molecules (A and B in the asymmetric unit. In each case, the piperidine ring exists in a twist-boat conformation. The dihedral angle between the phenyl rings is 46.16 (12° in molecule A and 44.95 (12° in molecule B. In both molecules, the allyl side chain is disordered over two orientations in a 0.649 (9:0.351 (9 ratio for molecule A and 0.826 (10:0.174 (10 ratio for molecule B. In the crystal, neither molecule forms a hydrogen bond from its N—H group, presumably due to steric hindrance. A+A and B+B inversion dimers are formed, linked by pairs of weak C—H...O hydrogen bonds enclosing R22(22 ring motifs.

  16. Crystal structure of N-(1-allyl-3-chloro-4-ethoxy-1H-indazol-5-yl-4-methoxybenzenesulfonamide

    Directory of Open Access Journals (Sweden)

    Hakima Chicha


    Full Text Available In the title compound, C19H20ClN3O4S, the benzene ring is inclined to the indazole ring system (r.m.s. deviation = 0.014 Å by 65.07 (8°. The allyl and ethoxy groups are almost normal to the indazole ring, as indicated by the respective torsion angles [N—N—C—C = 111.6 (2 and C—C—O—C = −88.1 (2°]. In the crystal, molecules are connected by N—H...N hydrogen bonds, forming helical chains propagating along [010]. The chains are linked by C—H...O hydrogen bonds, forming a three-dimensional network.

  17. Crystal structure of (Z-3-allyl-5-(4-chlorobenzylidene-2-sulfanylidene-1,3-thiazolidin-4-one

    Directory of Open Access Journals (Sweden)

    Rahhal El Ajlaoui


    Full Text Available In the title compound, C13H10ClNOS2, the dihedral angle between the rhodanine (r.m.s. deviation = 0.008 Å and 4-chlorobenzylidene rings is 1.79 (11°. The allyl group attached to the N atom, which lies almost perpendicular to the rhodanine ring, is disordered over two orientations in a 0.519 (13:0.481 (13 ratio. A short intramolecular C—H...S interaction closes an S(6 ring. In the crystal, molecules are linked by π–π stacking interactions [centroid–centroid separation = 3.600 (15 Å], generating inversion dimers.

  18. Diazonium salt-mediated synthesis of new amino, hydroxy, propargyl, and maleinimido-containing superparamagnetic Fe@C nanoparticles as platforms for linking bio-entities or organocatalytic moieties

    Energy Technology Data Exchange (ETDEWEB)

    Bunge, Alexander; Magerusan, Lidia [National Institute of Research and Development for Isotopic and Molecular Technologies (Romania); Morjan, Ion [National Institute for Lasers, Plasma and Radiation Physics (Romania); Turcu, Rodica; Borodi, Gheorghe; Liebscher, Jürgen, E-mail: [National Institute of Research and Development for Isotopic and Molecular Technologies (Romania)


    New magnetic Fe@C nanoparticles in the size range of about 20–50 nm functionalized with amino, hydroxy, propargyl, or maleinimido groups were synthesized by reaction with aryl diazonium salts. Aryl diazonium salts wherein the functional groups are linked via a sulfonamide moiety turned out to be advantageous over those with direct linkage. The obtained Fe@C nanoparticles represent magnetic nanoplatforms for linking bio-entities and organocatalysts using amide formation, CuAAC, or thiol-ene click chemistry as exemplified by selected examples. The Fe@C nanoparticles obtained exhibit supramolecular behavior with high value of saturation magnetization rendering them attractive for practical applications in biomedicine and organocatalysis.

  19. Stereochemistry of Pd(II)-Catalyzed THF Ring Formation of ε-Hydroxy Allylic Alcohols and Synthesis of 2,3,5-Trisubstituted and 2,3,4,5-Tetrasubstituted Tetrahydrofurans. (United States)

    Murata, Yuki; Uenishi, Jun'ichi


    Pd(II)-catalyzed ring formation of 2,3,5-trisubstituted and 2,3,4,5-tetrasubstituted tetrahydrofurans is described. Oxypalladation of a chiral ε-hydroxy allylic alcohol provides a 5-alkenyltetrahydrofuran ring in excellent yields via a 5-exo-trigonal process. Nine substrates including six secondary allylic alcohols and three primary allylic alcohols with or without an additional secondary hydroxy substituent at the γ-position have been examined. Their structures are restricted by a 2,2,4,4-tetraisopropyl-1,3,5,2,4-trioxadisilocane ring. The stereochemistry of the resulting tetrahydrofuran products was determined by chemical transformation. The reaction mechanism is discussed on the basis of the stereochemical results. The steps in the chiral allylic alcohol directed or the nucleophilic alcohol directed facial selection for the formation of the alkene-Pd(II)-π-complex, the cis-oxypalladation, and a syn-elimination mechanism account for the observed stereochemistry of the reaction.

  20. 超硬材料磨具用烯丙基化酚醛改性双马来酰亚胺树脂的研究%Bismaleimide Modified by Allyl Novolak for Superabrasives

    Institute of Scientific and Technical Information of China (English)

    郑红飞; 李志宏; 朱玉梅


    A novel thermosetting resin system for superabrasives based on novolak and bismaleimide (BMI) was developed.The novolak resin was allylated and then copolymerized with BMI.The structure of allyl novolak and reaction mechanism were analyzed by FTIR.Thermal and mechanical properties were characterized by using comprehensive thermal analyzer (DSC-TG) and strength tester,respectively.The results showed that high molecular weight of novolak was advantageous for heat-resistance,but was unfavorable for the bending strength.High allyl content improved the heat-resistance but lowered the bending strength.When the molecular weight of novolak was 450 and allyl content was 50%,the best resin system with good heat-resistance and bending strength was obtained.It was suitable for the manufacturing of superabrasive tools.

  1. A one-pot stereoselective synthesis of 1,4-dienyl selenides by hydrostannylation-Stille tandem reaction of acetylenic selenides with Bu3SnH and allylic bromides

    Institute of Scientific and Technical Information of China (English)

    La Mei Yu; Wen Yan Hao; Ming Zhong Cai


    1,4-Dienyl selenides can be stereoselectively synthesized in one pot under mild conditions in good yields by the palladium-catalyzed hydrostannylation of acetylenic selenides, followed by Stille coupling with allylic bromides.

  2. H2SO4中丙炔醇复配缓蚀剂对碳钢的缓蚀作用%Inhibition Performances of Compounds of Propargyl Alcohol Inhibitior for Carbon Steel in H2SO4 Solution

    Institute of Scientific and Technical Information of China (English)

    李珊; 杨丽; 芮玉兰


    ABSTRACT:Objective To study the inhibition ability of propargyl alcohol, potassium iodide and compound in 10% H2SO4 for Q235 carbon steel and N80 sheet steel at different temperature.Methods In this paper, the inhibition performance of the sin-gle dosage was measured by static weight-loss method and electrochemical method for Q235 carbon steel at 60℃, and then the compound was studied. The experimental temperature was increased after optimized to research the corrosion inhibition for N80 steel in acid solution with different proportions. The inhibitory mechanism was investigated by isothermal adsorption model and corrosion kinetics.Results The results reveal that if propargyl alcohol and potassium iodide were used alone to inhibit the corro-sion reaction in H2SO4 solution, the inhibition rate for Q235 carbon steel reached 90% at 60℃ whenthe concentrations were 120 mg/L and 1000 mg/L. There were two preferred ratios. The concentration A was propargyl alcohol 18 mg/L and KI 250 mg/L and that of B was propargyl alcohol 15 mg/L and KI 300 mg/L. The inhibition efficiency of them reached 98% at 60℃, that of A reached 93% at 80℃ for N80 and that of B reached 73% in H2SO4 environment at 100℃. The inhibition efficiencies decreased with increase in the temperature of the inhibitors.Conclusion The compounds sharply decrease after the concentra-tions of propargyl alcohol and potassium iodide and have good inhibition performance at high temperature. The synergistic ef-fect between them is obviously good. Results obtained from weight loss and electrochemistry methods are in good agreement. The results show that propargyl alcohol and compounds are mixed type corrosion inhibitors. The adsorption of these inhibitors on mild steel surface is chemical adsorption and obeys Langmiur isotherm.%目的:探究不同温度下丙炔醇、KI及其复配对Q235碳钢和N80钢片在10%(质量分数)硫酸中的缓蚀性能。方法采用静态失重法和电化学方法,60℃

  3. Role of cluster size and substrate in the gas phase CC bond coupling reactions of allyl halides mediated by Agn+ and Agn-1H+ cluster cations (United States)

    Wang, Farrah Qiuyun; Khairallah, George N.; O'Hair, Richard A. J.


    Previous studies have demonstrated that the silver hydride cluster cation Ag4H+ promotes CC bond coupling of allylbromide [G.N. Khairallah, R.A.J. O'Hair, Angewandte Chemie International Edition 44 (2005) 728]. Here the influence of both the nature and the size of the silver cluster cation and the substrate on CC bond coupling are examined. Thus each of the cations Ag2H+, Ag4H+, Ag3+, and Ag5+ were allowed to react with three different halides: allyl chloride, allyl bromide and allyl iodide. No CC bond coupling is observed in the reactions of the cluster cations with allyl chloride. There are four main reaction sequences that result in CC bond coupling for allyl bromide and allyl iodide mediated by Agn+ and Agn-1H+ clusters: (i) A sequence involving the reactions of silver cluster cations with two molecules of C3H5X: Agn+ --> Agn(C3H5X)+ --> AgnX2+. This only occurs in the cases of: n = 3 and X = I; n = 5 and X = Br. (ii) A sequence involving the reactions of silver cluster cations with two molecules of C3H5X via an organometallic intermediate: Agn+ --> Agn-1(C3H5)+ --> Agn-1X+. This only occurs in the cases of: n = 5 and X = Br and I. (iii) A sequence involving the reactions of silver hydride cluster cations with three molecules of C3H5X: Agn-1H+ --> Agn-1X+ --> Agn-1X(C3H5X)+ --> Ag(C3H5)2+ and Agn-1X3+. This only occurs in the cases of: n = 5 and X = Br and I. (iv) A sequence involving the reactions of silver hydride cluster cations with three molecules of C3H5X via an organometallic intermediate: Agn-1H+ --> Agn-1X+ --> Agn-3(C3H5)+ --> Ag(C3H5)2+ and Agn-3X+. This only occurs in the cases of: n = 5 and X = I.

  4. Design and fabrication of microfluidic mixer from carbonyl iron–PDMS composite membrane

    KAUST Repository

    Li, Jiaxing


    This paper introduces a carbonyl iron-PDMS (CI-PDMS) composite magnetic elastomer in which carbonyl iron (CI) particles are uniformly distributed in a PDMS matrix. The CI particles and the PDMS were mixed at different weight ratios and tested to determine the influence of CI concentration. The magnetic and mechanical properties of the magnetic elastomers were characterized, respectively, by vibrating-sample magnetometer and by tensile testing using a mechanical analyzer. The elastomer was found to exhibit high magnetization and good mechanical flexibility. The morphology and deformation of the CI-PDMS membrane also were observed. A magnetically actuated microfluidic mixer (that is, a micromixer) integrated with CI-PDMS elastomer membranes was successfully designed and fabricated. The high efficiency and quality of the mixing makes possible the impressive potential applications of this unique CI-PDMS material in microfluidic systems. © Springer-Verlag 2010.

  5. The N-heterocyclic carbene chemistry of transition-metal carbonyl clusters. (United States)

    Cabeza, Javier A; García-Álvarez, Pablo


    In the last decade, chemists have dedicated many efforts to investigate the coordination chemistry of N-heterocyclic carbenes (NHCs). Although most of that research activity has been devoted to mononuclear complexes, transition-metal carbonyl clusters have not escaped from these investigations. This critical review, which is focussed on the reactivity of NHCs (or their precursors) with transition-metal carbonyl clusters (mostly are of ruthenium and osmium) and on the transformations underwent by the NHC-containing species initially formed in those reactions, shows that the polynuclear character of these metallic compounds or, more precisely, the close proximity of one or more metal atoms to that which is or can be attached to the NHC ligand, is responsible for reactivity patterns that have no parallel in the NHC chemistry of mononuclear complexes (74 references).

  6. The kinetics and mechanism of dissociation of metal carbonyls in high infrared laser fields (United States)

    Langsam, Y.; Ronn, A. M.


    The method of laser induced dielectric breakdown has been used to study the dissociation of three metal carbonyls. Following non-resonant excitation by a TEA CO 2 laser, amorphous micro-metallic particles are deposited. The identity of the various species within a laser induced plasma for a series of related reactant molecules, has been determined using infrared and visible real time fluorescence techniques. Based upon the energetics of dissociation and the relative magnitudes of the rates of activation and deactivation for various collision partners of the plasma fluorescence, an energy transfer map as well as probable mechanisms are proposed. The kinetics of a variety of chemical reactions under plasma conditions are discussed in terms of elementary collision theory. It is shown that the internal vibration manifold of the metal carbonyls is equilibrated prior to the dissociation in agreement with the majority of laser induced multiphoton dissociation experiments.

  7. A catalyst for the carbonylation of methanol to acetic acid in gaseous phase

    Institute of Scientific and Technical Information of China (English)

    潘平来; 柳忠阳; 朱长城; 袁国卿


    A novel Rh/Ys catalyst for the carbonylation of methanol to acetic acid in gaseous phase is reported. The porous carbon beads (Ys) prepared from the carbonation of poly(vinylidene chloride) were used as the support. This catalyst has a specific surface area of 1 000 m2/g, high mechanical strength and thermal stability. The average diameter of the pore is in the range of 0.8 - 1.2nm. Experimental evidence showed that this catalyst was of high activity and selectivity, which could compare to those of the homogeneous catalyst from Monsanto. The catalytic rate could get to 900 g AcOH/g Rh·h during the carbonylation of methanol to acetic acid. The fine spreading of Ph over the Ys surface is the key factor for the activity.

  8. Impact of lipid content and composition on lipid oxidation and protein carbonylation in experimental fermented sausages. (United States)

    Fuentes, Verónica; Estévez, Mario; Ventanas, Jesús; Ventanas, Sonia


    This study aims to investigate the effect of lipid content (∼4%, ∼10% and ∼15%) and composition (different lipid sources; animal fat and sunflower oil) on the oxidative stability of proteins and lipids in experimental fermented sausages. Increasing the lipid content of sausages enhanced the susceptibility of lipids to oxidation whereas the effect on the formation of specific carbonyls from protein oxidation was not so evident. Sausages manufactured with different lipid sources affected the susceptibility of lipids and proteins to oxidation as a likely result of the modifications in the fatty acid profile, as well as to the presence of antioxidant compounds. While the fatty acid profile had a major effect on the occurrence and extent of lipid oxidation, the presence of compounds with potential antioxidant activity may be more influential on the extent of protein carbonylation.

  9. Rheological properties of magnetorheological fluid prepared by gelatin-carbonyl iron composite particles

    Institute of Scientific and Technical Information of China (English)

    PAN Hua-jin; HUANG Hong-jun; ZHANG Ling-zhen; QI Jian-ying; CAO Shao-kun


    Gelatin-carbonyl iron composite particle was prepared by micro emulsion method. The analysis of scanning electron microscope(SEM) shows that the ultrafine particles are spheroids coated by gelatin, and the average sizes of particles are 3-10 μm. The specific saturation magnetization σs is 130.9 A·m2/kg, coercivity Hc is 0.823 A/m, and residual magnetism r is 4.98 Am2/kg for the composite particles. It is shown that the particles possess properties of soft magnetic. The yield stress of magnetorheological fluid(MRF) with composite particle reaches 70 kPa at 0.5 T magnetic induction. Magnetorheological effects are superior in lower magnetic field intensity and the subsidence stability of the MRF is excellent compared with pure carbonyl iron powder.

  10. A Review on Mutagenicity Testing for Hazard Classification of Chemicals at Work: Focusing on in vivo Micronucleus Test for Allyl Chloride. (United States)

    Rim, Kyung-Taek; Kim, Soo-Jin


    Chemical mutagenicity is a major hazard that is important to workers' health. Despite the use of large amounts of allyl chloride, the available mutagenicity data for this chemical remains controversial. To clarify the mutagenicity of allyl chloride and because a micronucleus (MN) test had not yet been conducted, we screened for MN induction by using male ICR mice bone marrow cells. The test results indicated that this chemical is not mutagenic under the test conditions. In this paper, the regulatory test battery and several assay combinations used to determine the genotoxic potential of chemicals in the workplace have been described. Further application of these assays may prove useful in future development strategies of hazard evaluations of industrial chemicals. This study also should help to improve the testing of this chemical by commonly used mutagenicity testing methods and investigations on the underlying mechanisms and could be applicable for workers' health.

  11. Structure and stability of acrolein and allyl alcohol networks on Ag(111) from density functional theory based calculations with dispersion corrections (United States)

    Ferullo, Ricardo M.; Branda, Maria Marta; Illas, Francesc


    The interaction of acrolein and allyl alcohol with the Ag(111) surface has been studied by means of periodic density functional theory based calculations including explicitly dispersion terms. Different coverage values have been explored going from isolated adsorbed molecules to isolated dimers, interacting dimers or ordered overlayers. The inclusion of the dispersion terms largely affects the calculated values of the adsorption energy and also the distance between adsorbed molecule and the metallic surface but much less the adsorbate-adsorbate interactions. Owing to the large dipole moment of acrolein, the present calculations predict that at high coverage this molecule forms a stable extensive two-dimensional network on the surface, caused by the alignment of the adsorbate dipoles. For the case of allyl alcohol, dimers and complex networks exhibit similar stability.

  12. A formal [3,3]-sigmatropic rearrangement route to quaternary alpha-vinyl amino acids: use of allylic N-PMP trifluoroacetimidates. (United States)

    Berkowitz, David B; Wu, Bin; Li, Huijie


    Pd(II)-mediated rearrangement of allylic N-PMP (p-methoxyphenyl) trifluoroacetimidates provides the first formal sigmatropic route to quaternary, alpha-vinylic amino acids, potential suicide substrates for PLP enzymes. The amino acid side chains enter via transition-metal-mediated C-C bond constructions, including (i) Cu(I)-mediated conjugate addition (Ala); (ii) Pd(0)/AsPh3-mediated Stille coupling (allyl-Gly, Phe, DOPA, m-Tyr); and (iii) Pd(0)/Pt-Bu3-mediated Negishi coupling (Leu). In the synthesis of the DOPA decarboxylase inactivator, alpha-vinyl-m-tyrosine, the new N-PMP trifluoroacetimidate rearranges much more efficiently than the corresponding trichloroacetimidate.

  13. Remarkable rate acceleration of SmI3-mediated iodination of acetates of Baylis-Hillman adducts in ionic liquid: facile synthesis of (Z)-allyl iodides

    Institute of Scientific and Technical Information of China (English)


    Stereoselective transformation of Baylis-Hillman acetates 1 into corresponding (Z)-allyl iodides 2 has been achieved by treatment of 1 with samarium triiodide in THF. Remarkable rate acceleration of samarium triiodide-mediated iodination of 1 was found when ionic liquid 1-n-butyl-3-methyl-imidazolium tetrafluroborate ([bmim]BF4) was used as reaction media in stead of THF. This novel approach proceeds readily at 50 ℃ within a few minutes to afford (Z)-allyl iodides 2 in excellent yields. A mechanism involving stereoselective iodination of the acetates of Baylis-Hillman adducts by samarium triiodide is described, in which a six-membered ring transition state played a key role in the stereoselective formation of 2.

  14. Microfluidic lab-on-a-chip derivatization for gaseous carbonyl analysis. (United States)

    Pang, Xiaobing; Lewis, Alastair C; Ródenas-García, Milagros


    We present a microfluidic lab-on-a-chip derivatization technique for the analysis of gaseous carbonyl compounds using O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA) as the derivatizing reagent. The novel microfluidic lab-on-a-chip derivatization technique has been developed to measure nmol per mole (ppbv) mixing ratios of gaseous carbonyl compounds, which are of particular importance to atmospheric chemistry. The technique utilised a planar glass microreactor comprising three inlets and one outlet, gas and fluid splitting and combining channels, mixing junctions, and a 2.0m long, 620μm internal diameter reaction microchannel. The microreactor integrated three functions, providing: (1) a gas and liquid mixer and reactor, (2) reagent heating, and (3) sample pre-concentration. The concentration of derivatization solution, the volumetric flow rates of the incoming gas sample and PFBHA solution, and the temperature of the microreactor were optimised to achieve a near real-time measurement. The enhanced phase contact area-to-volume ratio and the high heat transfer rate in the microreactor resulted in a fast and high efficiency derivatization reaction, generating an effluent stream which was ready for direct introduction to GC-MS. Good linearity was observed for eight carbonyl compounds over the measurement ranges of 1-500ppbv when they were derivatized under optimal reaction conditions. The method detection limits (MDLs) were below 0.10nmolmol(-1) for most carbonyls in this study, which is below or close to their typical concentrations in clean ambient air. The performance of the technique was assessed by applying the methodology to the quantification of glyoxal (GLY) and methylglyoxal (MGLY) formed during isoprene photo-oxidation in an outdoor photoreactor chamber (EUPHORE). Good agreements between GLY and MGLY measurements were obtained comparing this new technique with Fourier Transform InfraRed (FTIR), which provides support for the potential effectiveness of

  15. Influence of shape anisotropy on microwave complex permeability in carbonyl iron flakes/epoxy resin composites

    Institute of Scientific and Technical Information of China (English)

    Wen Fu-Sheng; Qiao Liang; Zhou Dong; Zuo Wen-Liang; Yi Hai-Bo; Li Fa-Shen


    To explore the mechanism of carbonyl iron flake composites for microwave complex permeability, this paper investigates the feature of the flakes. The shape anisotropy was certified by the results of the magnetization hysteresis loops and the Mossbauer spectra. Furthermore, the shape anisotropy was used to explain the origin of composite microwave performance, and the calculated results agree with the experiment. It is believed that the shape anisotropy dominates microwave complex permeability, and the natural resonance plays main role in flake.

  16. Carbonylative Heck Reactions Using CO Generated ex Situ in a Two-Chamber System

    DEFF Research Database (Denmark)

    Hermange, Philippe; Gøgsig, Thomas; Lindhardt, Anders Thyboe;


    A carbonylative Heck reaction of aryl iodides and styrene derivatives employing a two-chamber system using a stable, crystalline, and nontransition metal based carbon monoxide source is reported. By applying near-stoichiometric amounts of the carbon monoxide precursor, an effective exploitation o...... of the hazardous CO gas is obtained affording chalcone derivatives in good yields. Application to isotope labeling, incorporating 13CO, was further established....

  17. Coupling Reaction of Carbonyl Compounds Mediated by Gallium Metal in Aqueous Media

    Institute of Scientific and Technical Information of China (English)

    汪志勇; 袁仕祯; 查正根; 张祖德


    A simple and effective pinacol coupling of various aromatic aldehydes mediated by gallium in good yields has been carried out. The reaction is highly effective in water in the prurience of KOH or HCl and was strongly affected by the steric environ-ment surrounding the carbonyl group. Aliphaflc aldehydes, ke-tones and aromatic ketones appear inert under the same reac-tion conditions.

  18. Influence of carbonyl stress on rheological alterations of blood materials and decarbonylation effect of glutathione

    Institute of Scientific and Technical Information of China (English)

    彭密军; 蔡建光; 贺洪; 龚萍; 李国林; 汤婷; 朱泽瑞; 印大中


    The effects of various toxic carbonyls such as malondialdehyde(MDA),a secondary product of lipid peroxidation,and other aldehydes on rheological parameters and their relationship with aging-associated alterations were studied.Both MDA and glutaraldehyde(Glu) in different concentrations significantly increase viscosity,plastic viscosity and yield stress of human plasma and erythrocyte suspensions.MDA(20 mmol/L) reduces sharply the typical fluorescence of proteins(excitation 280 nm/emission 350 nm),and produces age pigment-like fluorescence with a strong emission peak at 460 nm when excites at 395 nm by only being incubated for some hours.In contrast,Glu decreases merely the fluorescence of proteins without producing age pigment-like fluorescence.These data suggest interestingly that the MDA-induced gradual protein cross linking seems to form from different mechanisms compared to the fast rheological changes of blood materials which may take place either in acute and chronic diseases or during aging.On the other hand,MDA induces various deleterious alterations of erythrocytes whereas glutathione(GSH) inhibits the MDA-related carbonyl stress in a concentration-dependent manner.The results indicate that carbonyl-amino reaction exists in the blood widely and GSH has the ability to interrupt or reverse this reaction in a certain way.It implies that carbonyl stress may be one of the important factors in blood stasis and suggests a theoretical and practical approach in anti-stresses and anti-aging.

  19. Formation of Small Gas Phase Carbonyls from Heterogeneous Oxidation of Polyunsaturated Fatty Acids (PUFA) (United States)

    Zhou, S.; Zhao, R.; Lee, A.; Gao, S.; Abbatt, J.


    Fatty acids (FAs) are emitted into the atmosphere from gas and diesel powered vehicles, cooking, plants, and marine biota. Field measurements have suggested that FAs, including polyunsaturated fatty acids (PUFA), could make up an important contribution to the organic fraction of atmospheric aerosols. Due to the existence of carbon-carbon double bonds in their molecules, PUFA are believed to be highly reactive towards atmospheric oxidants such as OH and NO3 radicals and ozone, which will contribute to aerosol hygroscopicity and cloud condensation nuclei activity. Previous work from our group has shown that small carbonyls formed from the heterogeneous reaction of linoleic acid (LA) thin films with gas-phase O3. It is known that the formation of small carbonyls in the atmosphere is not only relevant to the atmospheric budget of volatile organic compounds but also to secondary organic aerosol formation. In the present study, using an online proton transfer reaction mass spectrometry (PTR-MS) and off-line gas chromatography-mass spectrometry (GC-MS) we again investigated carbonyl formation from the same reaction system, i.e. the heterogeneous ozonolysis of LA film. In addition to the previously reported carbonyls, malondialdehyde (MDA), a source of reactive oxygen species that is mutagenic, has been identified as a product for the first time. Small dicarbonyls, e.g. glyoxal, are expected to be formed from the further oxidation of MDA. In this presentation, the gas-phase chemistry of MDA with OH radicals using a newly built Teflon chamber in our group will also be presented.

  20. Characterization of Carbonyl Compounds in the Ambient Air of an Industrial City in Korea

    Directory of Open Access Journals (Sweden)

    Sung-Ok Baek


    Full Text Available The purpose of this study was to characterize spatial and temporal variations of carbonyl compounds in Gumi city, where a number of large electronic-industrial complexes are located. Carbonyl samples were collected at five sites in the Gumi area: three industrial, one commercial, and one residential area. Sampling was carried out throughout a year from December 2003 to November 2004. At one industrial site, samples were taken every six days, while those of the other sites were for seven consecutive days in every season. Each sample was collected for 150 minutes and at intervals of three times a day (morning, afternoon, and evening. A total of 476 samples were analyzed to determine 15 carbonyl compounds by the USEPA TO-11A (DNPH-cartridge/HPLC method. In general, acetaldehyde appeared to be the most abundant compound, followed by formaldehyde, and acetone+acrolein. Mean concentrations of acetaldehyde were two to three times higher in the industrial sites than in the other sites, with its maximum of 77.7 ppb. In contrast, ambient levels of formaldehyde did not show any significant difference between the industrial and non-industrial groups. Its concentrations peaked in summer probably due to the enhanced volatilization and photochemical reactivity. These results indicate significant emission sources of acetaldehyde in the Gumi industrial complexes. Mean concentrations of organic solvents (such as acetone+acrolein and methyl ethyl ketone were also significantly high in industrial areas. In conclusion, major sources of carbonyl compounds, including acetaldehyde, are strongly associated with industrial activities in the Gumi city area.