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New potential biologically active compounds: design and an efficient synthesis of N-substituted 4-aryl-4,6,7,8-tetrahydroquinoline-2,5(1H,3H)-diones under microwave irradiation.  

Science.gov (United States)

A series of N-substituted 4-aryl-4,6,7,8-tetrahydroquinoline-2,5(1H,3H)-diones were synthesized through a rapid one-pot four-component reaction under microwave irradiation. The method has the advantages of excellent yields (82-96%) and short reaction time (4-9 min). We provide new series of potential biologically active compounds for biomedical screening. PMID:16563758

Tu, Shujiang; Zhu, Xiaotong; Zhang, Jinpeng; Xu, Jianing; Zhang, Yan; Wang, Qian; Jia, Runhong; Jiang, Bo; Zhang, Junyong; Yao, Changsheng

2006-06-01

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Palladium-Catalyzed Carbonylation of Aryl Bromides with N-Substituted Cyanamides  

DEFF Research Database (Denmark)

The palladium(0)-catalyzed three-component coupling reaction of aryl bromides, carbon monoxide, and N-alkyl cyan­amides has been developed employing a two-chamber system with ex situ generation of carbon monoxide from a silacarboxylic acid. The reactions proceeded well and were complete with a reaction time of only five hours leading to the corresponding N-alkyl cyanamides in good yields. The methodology was further extended to 13C isotope labeling of the carbonyl group through the use of a 13CO produced from the corresponding 13C-labeled version of the sila­carboxylic acid.

Lian, Zhong; Friis, Stig D.

2014-01-01

3

Synthesis of N-substituted indole-3-carboxylic acid derivatives via Cu(I)-catalyzed intramolecular amination of aryl bromides.  

Science.gov (United States)

A variety of N-alkylated and N-arylated derivatives of methyl 1 H-indole-3-carboxylate were synthesized efficiently via Ullmann-type intramolecular arylamination, using the CuI-K 3PO 4-DMF system. This catalytic amination procedure can be performed with good to high yields under mild conditions under an air atmosphere. PMID:18471015

Melkonyan, Ferdinand S; Karchava, Alexander V; Yurovskaya, Marina A

2008-06-01

4

N-substituted iminodiacetic acids  

International Nuclear Information System (INIS)

The chemical preparation of several new N-substituted iminodiacetic acid derivatives are described. These compounds when complexed with sup(99m)Tc provide useful radiopharmaceuticals for the external imaging of the hepatobiliary system. (U.K.)

1982-01-01

5

UREA AND N-SUBSTITUTED UREA DERIVATIVES COMPOUNDS OF IRON (II) ARE SUITABLE INTERMEDIATES IN THE SYNTHESIS OF COMPLEXES MIMIKING THE NONHEME IRON-CONTAINING ENZIMES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Four complexes of iron (II) having as ligands only urea (or N-substituted ureaderivatives) and easily replaceable water molecules, having low molecular weight, an electrolyticnature and a reasonable stability in aqueous medium, were synthesised in order to be used asintermediates in the aqueous synthesis of other iron (II) compounds, with mixed ligands,mimicking anti-oxidant nonheme, iron-containing enzymes. The compounds were characterisedby analytical procedures, measurement of some physica...

2004-01-01

6

Screening candidate anticancer drugs for brain tumor chemotherapy: Pharmacokinetic-driven approach for a series of (E)-N-(substituted aryl)-3-(substituted phenyl)propenamide analogues  

Science.gov (United States)

Summary A pharmacokinetic [PK]-driven screening process was implemented to select new agents for brain tumor chemotherapy from a series of low molecular weight anticancer agents [ON27x] that consisted of 141 compounds. The screening procedures involved a combination of in silico, in vitro and in vivo mouse studies that were cast into a pipeline of tier 1 and tier 2 failures that resulted in a final investigation of 2 analogues in brain tumor-bearing mice. Tier 1 failures included agents with a molecular weight of > 450 Da, a predicted log P (log P) of either 3.5, and a cytotoxicity IC50 value of > 2 uM. Next, 18 compounds underwent cassette dosing studies in normal mice that identified compounds with high systemic clearance, and low blood-brain barrier [BBB] penetration. These indices along with a derived parameter, referred to as the brain exposure index, comprised tier 2 failures that led to the administration of 2 compounds [ON27570, ON27740] as single agents [discrete dosing] to mice bearing intracerebral tumors. Comparison of ON27570s resultant PK parameters to those obtained in the cassette dosing format suggested a drug-drug interaction most likely at the level of BBB transport, and prompted the use of the in vitro MDCK-MDR1 transport model to help assess the nature of the discrepancy. Overall, the approach was able to identify candidate compounds with suitable PK characteristics yet further revisions to the method, such as the use of in vitro metabolism and transport assays, may improve the PK-directed approach to identify efficacious agents for brain tumor chemotherapy.

Lv, Hua; Wang, Fan; Reddy, M.V. Ramana; Zhou, Qingyu; Zhang, Xiaoping; Reddy, E. Premkumar; Gallo, James M.

2012-01-01

7

cap alpha. ,. beta. -Unsatured thio compounds. XVII. synthesis and some chemical transformations of the thio dirivatives of 2-aryl-1-indanones and 2-aryl-1,3-indanediones  

Energy Technology Data Exchange (ETDEWEB)

In the reaction of 2-aryl-1-indanones and 2-aryl-1,3-indanediones with hydrogen sulfide in the presence of hydrogen chloride 2-aryl-3-indenethiols and 3-mercapto-2-aryl-1-indenethiones respectively are formed. The latter are readily acylated, condense with carbonyl compounds, are oxidized, and give 3-amino-2-aryl-1-indenethiones in reaction with amines in the presence of atmospheric oxygen or sulfur.

Petriashvili, K.A.; Usov, V.A.; Voronkov, M.G.

1986-08-01

8

CuI/L-proline-catalyzed coupling reactions of aryl halides with activated methylene compounds.  

Science.gov (United States)

[reaction: see text] The arylation of ethyl acetoacetate, ethyl benzoyl acetate, and diethyl malonate under the catalysis of CuI/L-proline in DMSO proceeds smoothly at 40-50 degrees C in the presence of Cs2CO3 to provide the 2-aryl-1,3-dicarbonyl compounds in good yields. Both aryl iodides and aryl bromides are compatible with these reaction conditions. PMID:16209512

Xie, Xiaoan; Cai, Guorong; Ma, Dawei

2005-10-13

9

Structural investigations of N,N'-substituted malonamide crystal compounds as a basis to support trivalent lanthanide extraction mechanisms  

International Nuclear Information System (INIS)

The problem of bond energies in the nitrato compounds of trivalent lanthanides, Ln, with malonamides, L, of the type: Ln(NO3)3(H2O)mL and Ln(NO3)3L2, (L=CH2(OCNR1R2)2) is approached through a semi-empirical theory connecting thermodynamic with structural properties (STT). Emphasis is given on the relation between bond energies and solvent extraction of complexes of Ln with L from nitric aqueous solutions. STT is presented and applied to nitrato compounds with R1=ethyl, R2=ethyl, R1=methyl, R2=cyclohexyl and R1=methyl, R2=phenyl. For the first time, the effect of the regular decrease of the bond energies Ln-O(nitrato) and Ln-O(L) with the increase of the volume of L is evidenced. The enthalpies of extraction of Ln by L from low nitric acid concentration are calculated. Finally, rules connecting the distribution coefficients D(Ln) in liquid-liquid extraction of Ln (III) by diamides is formulated. These rules appear as a useful guide to predict D(Ln) variation along the series. (orig.)

1998-07-24

10

Identification of new 4-N-substituted 6-aryl-7H-pyrrolo[2,3-d]pyrimidine-4-amines as highly potent EGFR-TK inhibitors with Src-family activity.  

Science.gov (United States)

The epidermal growth factor receptor is an important target in molecular cancer therapy. Herein, the enzymatic inhibition potential of a series of chiral and non chiral pyrrolopyrimidine based derivatives have been investigated and optimised. Overall, seven new compounds were identified having enzymatic IC50 values comparable to or better than the commercial drug Erlotinib. High activity was also confirmed towards the epidermal growth factor receptor L858R and L861Q mutants. Based on calculated druglike properties, eight compounds were further evaluated towards a panel of 52 other kinases revealing interesting Src-family kinase and colony stimulating factor 1 receptor kinase inhibitory activity. Cell proliferation studies with the cell lines A431, C-33A, AU-565, K-562 and genetically engineered Ba/F3-EGFR(L858R) cells also showed several molecules to be more active than Erlotinib, and thus confirming these pyrrolopyrimidines as attractive drug candidates or lead structures. PMID:24769040

Kaspersen, Svein Jacob; Han, Jin; Nrsett, Kristin G; Ryds, Line; Kjbli, Eli; Bugge, Steffen; Bjrky, Geir; Sundby, Eirik; Hoff, Brd Helge

2014-08-01

11

StructureActivity Relationships for a Novel Series of Dopamine D2-like Receptor Ligands Based on N-Substituted 3-Aryl-8-azabicyclo[3.2.1]octan-3-ol  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Discovering dopamine D2-like receptor subtype-selective ligands has been a focus of significant investigation. The D2R-selective antagonist 3-[4-(4-chlorophenyl)-4-hydroxypiperidinyl]methylindole (1, L741,626; Ki(D2R/D3R) = 11.2:163 nM) has previously provided a lead template for chemical modification. Herein, analogues have been synthesized where the piperidine was replaced by a tropane ring that reversed the selectivity seen in the parent compound, in human hD2LR- or hD3R-transfected HEK 29...

Paul, Noel M.; Taylor, Michelle; Kumar, Rakesh; Deschamps, Jeffrey R.; Luedtke, Robert R.; Newman, Amy Hauck

2008-01-01

12

Synthesis of some new biologically active N-substituted-2''- [(phenylsulfonyl)(piperidin-1-yl)amino]acetamide derivatives.  

Science.gov (United States)

A new series of N-aryl/aralkyl substitued-2"-[(phenylsulfonyl)(piperidin-1-yl)amino]acetamide (7a-k) was synthesized. These derivatives were geared up by the pairing of benzenesulfonyl chloride (4) with 1-aminopiperidine (5) under dynamic pH control in aqueous media to afford parent compound N-(Piperidin-1-yl) benzenesulfonamide (6), followed by the substitution at nitrogen atom with different electrophiles N-aryl/aralkyl-substituted-2-bromoacetamides (3a-k) in the presence of sodium hydride (NaH) and N,N-Dimethylformamide (DMF) to give a new series of N-substituted derivatives of acetamide (7a-k) bearing piperidine moiety. All the synthesized compounds were confirmed on the basis of IR, EIMS and (1)H-NMR spectral data. The synthesized compounds were evaluated against acetylcholinesterase and butyrylcholinesterase (AChE and BChE) respectively and lipoxygenase (LOX) enzymes. Almost all the synthesized compounds displayed promising activity but few of them remained inactive against lipoxygenase enzymes. PMID:24811811

Khalid, Hira; Rehman, Aziz-Ur; Abbasi, Muhammad Athar; Siddiqui, Sabahat Zahra; Malik, Abdul; Ashraf, Muhammad; Ahmad, Irshad; Ejaz, Syeda Abida

2014-05-01

13

Synthesis and In Vitro Antigungal Properties of 4-Aryl-4-Narylamine-1-butenes and Related Compounds  

Directory of Open Access Journals (Sweden)

Full Text Available A new series of 4-aryl and 4-alkyl-4-N-arylamine-1-butenes (homoallylamines were synthesized and some of them transformed to 4-aryl or alkylquinolines. All of them showed strong antifungal activities against human pathogenic fungi in vitro, being Epidermophyton floccosum the most susceptible species.

J. Urbina

2000-03-01

14

Unsymmetrical alkyl aryl thiourae compounds for use as cerebral blood flow tracers  

International Nuclear Information System (INIS)

The synthesis and characterization of an homologous series of inert nonvolatile 14C-labeled unsymmetrical alkyl aryl thiourea compounds is described for their use as regional blood flow (rCBF) tracers employing autoradiographic procedures. In alert normocapnic rats the single-pass extraction values into brain for these thioureas were found ranging from 0.497 for 1-methyl-3-phenylthiourea to 0.730 for 1-butyl-3-phenylthiourea. The commonly used rCBF tracers [14C] antipyrine and [14C] iodoantipyrine had single-pass extraction values of 0.451 and 0.553, respectively. Since 1-butyl-3-phenylthiourea diffused most readily into rat brain it was chosen as a potentially valuable rCBF tracer. Employing 1-butyl-3-phenylthiourea to measure rCBF nd its empirically derived brain extraction values the following flow rates in normocapnic rats were found: 3.2 ml . g-1 . min-1 for cochlear nucleus: 3.0 for inferior colliculus; 2.5 for medical geniculate; 1.9 for pontine gray and hypothalamus; 1.7 for caudate and cerebral cortex; and 1.2 for cerebellar gray and 0.41 to 0.50 for white matter structures. It was concluded from these studies that 1-butyl-3-phenylthiourea is more advantageous than iodoantipyrine for measuring rCBF, especially in those areas that possess very rapid rates of flow

1980-01-01

15

Unsymmetrical alkyl aryl thiourae compounds for use as cerebral blood flow tracers. [Rats  

Energy Technology Data Exchange (ETDEWEB)

The synthesis and characterization of an homologous series of inert nonvolatile /sup 14/C-labeled unsymmetrical alkyl aryl thiourea compounds is described for their use as regional blood flow (rCBF) tracers employing autoradiographic procedures. In alert normocapnic rats the single-pass extraction values into brain for these thioureas were found ranging from 0.497 for 1-methyl-3-phenylthiourea to 0.730 for 1-butyl-3-phenylthiourea. The commonly used rCBF tracers (14C) antipyrine and (14C) iodoantipyrine had single-pass extraction values of 0.451 and 0.553, respectively. Since 1-butyl-3-phenylthiourea diffused most readily into rat brain it was chosen as a potentially valuable rCBF tracer. Employing 1-butyl-3-phenylthiourea to measure rCBF nd its empirically derived brain extraction values the following flow rates in normocapnic rats were found: 3.2 ml . g-1 . min-1 for cochlear nucleus: 3.0 for inferior colliculus; 2.5 for medical geniculate; 1.9 for pontine gray and hypothalamus; 1.7 for caudate and cerebral cortex; and 1.2 for cerebellar gray and 0.41 to 0.50 for white matter structures. It was concluded from these studies that 1-butyl-3-phenylthiourea is more advantageous than iodoantipyrine for measuring rCBF, especially in those areas that possess very rapid rates of flow.

Goldman, S.S.; Haas, W.K.; Ransohoff, J.

1980-06-01

16

Electrochemical oxidation of propanil and related N-substituted amides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The electrochemical behaviour of propanil and related N-substituted amides (acetanilide and N,N-diphenylacetamide) was studied by cyclic and square wave voltammetry using a glassy carbon electrode. Propanil has been found to have chemical stability under the established analytical conditions and showed an oxidation peak at +1.27V versus Ag/AgCl at pH 7.5. N,N-diphenylacetamide has a higher oxidation potential than the other compounds of +1.49V versus Ag/AgCl. Acetanilide oxidation occurre...

2001-01-01

17

Alkylation of N-substituted 2-phenylacetamides  

Directory of Open Access Journals (Sweden)

Full Text Available Various N-substituted phenylacetamides were alkylated using different alkylating agents under neutral and basic conditions. Reactions were performed at different reaction temperatures and in various solvents. Also, a number of various catalysts were used including phase-transfer catalysts. Reactions were followed using GC or GC-MS technique and the presence as well as the yields of the alkylation products were established. Generally, the best yield and high selectivity in the studied reactions were achieved under basic conditions where in the certain cases some products, mostly N-product, were obtained solely in quantitative yields.

SLOBODAN D. PETROVIC

2004-10-01

18

Coordintion and hydrogenation of 1,3-cyclohexadiene by niobium and tantalum aryl oxide compounds: Relevance to catalytic arene hydrogenation  

Energy Technology Data Exchange (ETDEWEB)

In this paper we report the synthesis and chemistry of a series of new {eta}{sup 4}-cyclohexadiene derivatives of niobium and tantalum containing aryl oxide ligation. This synthetic work is complemented by an investigation of the reactivity of previously isolated tantalum hydride compounds as well as related niobium catalysts toward 1,3-cyclohexadiene and cyclohexene. The studies reported here focus on gaining a better insight into the overall mechanism of arene hydrogenation by this specific pedigree of catalyst. The mechanistic implications of stoichiometric and catalytic reactions are discussed. 48 refs., 8 figs., 6 tabs.

Visciglio, V.M.; Clark, J.R.; Nguyen, M.T.; Mulford, D.R.; Fanwick, P.E.; Rothwell, I.P. [Purdue Univ., West Lafayette, IN (United States)

1997-04-16

19

Effective heterogeneous palladium catalysis of reactions of organic boron compounds with aryl halides  

International Nuclear Information System (INIS)

Reactions of [Ph4B]Na and ArB(OH)2 with aryl halides ArX (X = F-I) are effectively catalyzed by heterogeneous Pd-catalists: PdCl2/C, Pd(0)/C and Pd-black to give cross-coupling products in high yields

1997-01-01

20

Synthesis and crystal structure of N-(3-benzylamino-2- cyano-3-methylthioacrylyl-N'-(substituted phenylureas  

Directory of Open Access Journals (Sweden)

Full Text Available Phenylurea groups were introduced into the frame of traditional cyanoacrylate and a series of N-(3-benzylamino-2-cyano-3-methylthioacrylyl-N'-(substituted phenylureas were synthesized. All compounds are new and their structures were confirmed by 1H NMR, 13C NMR and mass spectral analyses.

D.M. Wei

2013-05-01

 
 
 
 
21

S-(N-substituted aminomethyl) thioamides of thioglycolic acid as additives to lubricants  

Energy Technology Data Exchange (ETDEWEB)

With the aim of searching for effective additives to oils, S-(N-substituted aminomethyl)thioamides of thioglycolic acid have been synthesized and investigated. The compounds synthesized have been characterized by IR and PMR spectra. It has been established that the introduction of alkylaminomethyl groups into thioamide molecules improves the anticorrosion properties of the thioamides.

Kuliyev, A.B.; Abdullayeva, M.I.; Akhadov, N.O. [Institute of Chemistry of Additives, Baku (Azerbaijan)] [and others

1993-12-31

22

Biotransformation and Biodegradation of N-Substituted Aromatics in Methanogenic Granular Sludge.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

N-substituted aromatic compounds are environmental contaminants associated with the production and use of dyes, explosives, pesticides and pharmaceuticals among others. Nitro- and azo-substituted aromatic compounds with strong electron withdrawing groups are poorly biodegradable in aerobic treatment systems. Therefore anaerobic treatment technologies were considered in this research. The toxicity of these compounds to methanogenic bacteria was studied. Batch toxicity assays indicated that nit...

1997-01-01

23

Group IB Organometallic Chemistry XXXIV: Thermal behavior and chemical reactivity of tetranuclear Me2N-substituted diarylpropenylcopper-copper anion (Vi2Cu4X2) and mixed diarylpropenyl/organocopper (Vi2Cu4R2) compounds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermal decomposition of configurationally pure 1, 2-diarylpropenylcopper compounds Z-Vi{2}CU{4}Br{2} and Z-Vi{2}Cu{4}R{2} [Vi @? (2-Me{2}NC{6}H{4})C@?C(Me)-(C{6}H{4}Me-4), R @? 2-Me{2}NC{6}H{4} or 4-MeC{6}H{4}C@?C] predominantly results in the formation of ViH. In contrast, only dimers (ViVi) were formed on thermolysis of (Z-ViCu{2}OTf){@h} which is a further illustration of the influence of the counter anion on the reactivity of organocopper cluster compounds. However, in both cases partial...

Koten, G.; Hoedt, R. W. M. Ten; Noltes, J. G.

1980-01-01

24

Group ib organometallic chemistry. XXXIV. Thermal behaviour and chemical reactivity of tetranuclear Me2N-substituted diarypropenylcopper-copper anion (Vi2Cu4X2) and mixed diarylpropenyl/organocopper (Vi2Cu4R2) compounds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermal decomposition of configurationally pure 1,2-diarylpropenylcopper compounds Z-Vi2CU4Br2 and Z-Vi2Cu4R2 [Vi = (2-Me2NC6H4)C=C(Me)-(C6H4Me-4), R = 2-Me2NC6H4 or 4-MeC6H4CC] predominantly results in the formation of ViH. In contrast, only dimers (ViVi) were formed on thermolysis of (Z-ViCu2OTf)? which is a further illustration of the influence of the counter anion on the reactivity of organocopper cluster compounds. However, in both cases partial inversion of configuration, giving mixtur...

Hoedt, R. W. M. Ten; Koten, G.; Noltes, J. G.

1980-01-01

25

Occurrence of aryl hydrocarbon receptor agonists and genotoxic compounds in the river systems in Southern Taiwan.  

Science.gov (United States)

Water and sediment samples from river systems located in Southern Taiwan were investigated for the presence of aryl hydrocarbon receptor (AhR) agonists and genotoxicants by a combination of recombinant cell assays and gas chromatography-mass spectrometry analysis. AhR agonist activity and genotoxic response were frequently detected in samples collected during different seasons. In particular, dry-season water and sediment samples from Erren River showed strong AhR agonist activity (201-1423ngL(-1) and 1374-5631ngg(-1) ?-naphthoflavone equivalents) and high genotoxic potential. Although no significant correlation was found between AhR agonist activity and genotoxicity, potential genotoxicants in sample extracts were suggested to be causative agents for yeast growth inhibition in the AhR-responsive reporter gene assay. After high performance liquid chromatography fractionation, AhR agonist candidates were detected in several fractions of Erren River water and sediment extracts, while possible genotoxicants were only found in water extracts. In addition, polycyclic aromatic hydrocarbons, the typical contaminants showing high AhR binding affinity, were only minor contributors to the AhR agonist activity detected in Erren River sediment extracts. Our findings displayed the usefulness of bioassays in evaluating the extent of environmental contamination, which may be helpful in reducing the chances of false-negative results obtained from chemical analysis of conventional contaminants. Further research will be undertaken to identify major candidates for xenobiotic AhR agonists and genotoxicants to better protect the aquatic environments in Taiwan. PMID:24411837

Chou, Pei-Hsin; Liu, Tong-Cun; Ko, Fung-Chi; Liao, Mong-Wei; Yeh, Hsiao-Mei; Yang, Tse-Han; Wu, Chun-Ting; Chen, Chien-Hsun; Tsai, Tsung-Ya

2014-07-01

26

40 CFR 721.275 - Halogenated-N-(2-propenyl)-N-(substituted phenyl) acetamide.  

Science.gov (United States)

...2-propenyl)-N-(substituted phenyl) acetamide. 721.275 Section 721.275 ...2-propenyl)-N-(substituted phenyl) acetamide. (a) Chemical substances and significant...2-propenyl)-N -(substituted phenyl) acetamide (P-83-1085) is subject to...

2009-07-01

27

Development and Applications of Hypervalent Iodine Compounds : Powerful Arylation and Oxidation Reagents  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The first part of this thesis describes the efficient synthesis of several hypervalent iodine(III) compounds. Electron-rich diaryliodonium salts have been synthesized in a one-pot procedure, employing mCPBA as the oxidant. Both symmetric and unsymmetric diaryliodonium tosylates can be isolated in high yields. An in situ anion exchange also enables the synthesis of previously unobtainable diaryliodonium triflates. A large-scale protocol for the synthesis of a derivative of Kosers reagent, t...

Jalalian, Nazli

2012-01-01

28

Syntheses and antimalarial activities of N-substituted 11-azaartemisinins.  

Science.gov (United States)

A two-step reaction sequence between artemisinin and methanolic ammonia followed by treatment with Amberlyst 15 yielded 11-azaartemisinin in 65% yield. Substituting a variety of primary alkyl- and heteroaromatic amines for ammonia in the reaction sequence yields N-substituted 11-azaartemisinins in similar or greater yield. When Amberlyst 15 is replaced by a mixture of sulfuric acid/silica gel, both 11-azaartemisinin and the expected metabolite, 10-azadesoxyartemisinin, are formed in 45% and 15% yields, respectively. In vitro and in vivo test data for a number of novel N-substituted 11-azaartemisinins, against drug-resistant strains of Plasmodium falciparum, show they possess antimalarial activities equal to or greater than that of artemisinin. The most active derivative, N-(2'-acetaldehydo)-11-azaartemisinin, 17, was 26 times more active in vitro and 4 times more active in vivo than artemisinin. PMID:8544181

Torok, D S; Ziffer, H; Meshnick, S R; Pan, X Q; Ager, A

1995-12-22

29

Chemical reactivity and antimicrobial activity of N-substituted maleimides.  

Science.gov (United States)

Several N-substituted maleimides containing substituents of varying bulkiness and polarity were synthesised and tested for antimicrobial and cytostatic activity. Neutral maleimides displayed relatively strong antifungal effect minimum inhibitory concentrations (MICs in the 0.5-4 g ml(-1) range); their antibacterial activity was structure dependent and all were highly cytostatic, with IC(50) values below 0.1 g ml(-1). Low antimicrobial but high cytostatic activity was noted for basic maleimides containing tertiary aminoalkyl substituents. Chemical reactivity and lipophilicity influenced antibacterial activity of neutral maleimides but had little if any effect on their antifungal and cytostatic action. N-substituted maleimides affected biosynthesis of chitin and ?(1,3)glucan, components of the fungal cell wall. The membrane enzyme, ?(1,3)glucan synthase has been proposed as a putative primary target of N-ethylmaleimide and some of its analogues in Candida albicans cells. PMID:21612375

Salewska, Natalia; Boros-Majewska, Joanna; L?cka, Izabela; Chyli?ska, Katarzyna; Sabisz, Micha?; Milewski, S?awomir; Milewska, Maria J

2012-02-01

30

Synthesis of N-substituted iminosugars from 2'-carbonyl-C-glycofuranosides.  

Science.gov (United States)

Under basic conditions 2'-carbonyl 5-N-substituted-C-glycofuranosides undergo a tandem beta-elimination and intramolecular hetero-Michael addition to form N-substituted iminosugar derivatives in good to excellent yields. PMID:19917320

Luo, Hairong; Zou, Wei; Shao, Huawu

2009-12-14

31

Synthesis of Novel Lipophilic N-Substituted Norcantharimide Derivatives and Evaluation of Their Anticancer Activities  

Directory of Open Access Journals (Sweden)

Full Text Available This research attempted to study the effect of lipophilicity on the anticancer activity of N-substituted norcantharimide derivatives. Twenty-three compounds were synthesized and their cytotoxicities against five human cancer cell lines studied. The lipophilicity of each derivative was altered by its substituent, an alkyl, alkyloxy, terpenyl or terpenyloxy group at the N-position of norcantharimide. Further, among all synthesized derivatives studied, the compounds N-farnesyloxy-7-oxabicyclo[2.2.1]heptane-2,3-dicarboximide (9, and N-farnesyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboximide (18, have shown the highest cytotoxicity, anti-proliferative and apoptotic effect against human liver carcinoma HepG2 cell lines, yet displayed no significant cytotoxic effect on normal murine embryonic liver BNL CL.2 cells. Their overall performance led us to believe that these two compounds might be potential candidates for anticancer drugs development.

Jin-Yi Wu

2014-05-01

32

Synthesis of N-substituted N-nitrosohydroxylamines as inhibitors of mushroom tyrosinase.  

Science.gov (United States)

A series of N-substituted N-nitrosohydroxylamines including six new compounds were synthesized and examined for inhibition of mushroom tyrosinase. Corresponding hydroxylamines were reacted with n-butyl nitrite to give substituted nitrosohydroxylamines as their ammonium salt. The N-substituted hydroxylamines were prepared from the primary amines via the oxaziridine, or from the carbonyl compounds via the oxime. Most of the nitrosohydroxylamines tested inhibited mushroom tyrosinase. Among them, N-cyclopentyl-N-nitrosohydroxylamine exhibited the most potent activity (IC(50)=0.6 microM), as powerful as that of tropolone, one of the most powerful inhibitors. As removal of nitroso or hydroxyl moiety, the enzyme inhibitory activity was completely diminished. Both N-nitroso group and N-hydroxy group were suggested to be essential for the activity, probably by interacting with the copper ion at the active site of the enzyme. Lineweaver-Burk plotting showed that cupferron was a competitive inhibitor but that N-cyclopentyl-N-nitrosohydroxylamine was not. PMID:11377181

Shiino, M; Watanabe, Y; Umezawa, K

2001-05-01

33

40 CFR 721.225 - 2-Chloro-N-methyl-N-substituted acetamide (generic name).  

Science.gov (United States)

...2-Chloro-N-methyl-N-substituted acetamide (generic name). 721.225 Section...2-Chloro-N-methyl-N-substituted acetamide (generic name). (a) Chemical...2-chloro-N -methyl-N -substituted acetamide (PMN P-84-393) is subject...

2010-07-01

34

Naphthalene bisimides asymmetrically and symmetrically N-substituted with triarylamine - comparison of spectroscopic, electrochemical, electronic and self-assembly properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two semiconducting naphthalene bisimides were comparatively studied: NBI-(TAA)(2), symmetrically N-substituted with triaryl amine and asymmetric NBI-TAA-Oc with triaryl amine and octyl N-substituents. Both compounds show very similar spectroscopic and redox properties but differ in their supramolecular organization. As evidenced by STM, in monolayers on HOPG they form ordered 2D structures, however of different packing patterns. NBI-(TAA) 2 does not form ordered 3D structures, yielding amorph...

Rybakiewicz, Renata; Zapala, Joanna; Djurado, David; Nowakowski, Robert; Toman, Petr; Pfleger, Jiri; Verilhac, Jean-marie; Zagorska, Malgorzata; Pron, Adam

2013-01-01

35

Synthesis, Characterization and Antimicrobial Activity of 2-hydroxy-5-bromo-4- methoxy-N-(substituted phenyl chalconeimine  

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Full Text Available A series of 2-hydroxy-5-bromo-4-methoxy-N-(substituted phenyl chalconeimine was synthesized,characterized and tested for their antimicrobial activity. These new derivative was achieved by treating2-hydroxy-5-bromo-4-methoxy chalcone with substituted aniline at reflux temperature using ethanol assolvent in presence of H2SO4. Structures of the synthesized compounds were characterized using IR, 1HNMRand mass spectroscopy. The synthesized compounds were screened for their in vitro antibacterialactivity against bacteria S. aureus, E. coli, P. aeruginosa and S. Pyogenes. And antifungal activityagainst C. Albicans and A.Clavatus some of these compounds exhibited moderate to good activity.

Patil S

2013-05-01

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MICROWAVE ASSISTED SYNTHESIS OF FLUORO, CHLORO, 2-N (SUBSTITUTED SCHIFFS BASES AMINO BENZOTHIAZOLES FOR THEIR ANTIMICROBIAL AND ANTITUBERCULAR ACTIVITIES  

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Full Text Available The present research work is aimed to synthesize a series of various substituted benzothiazole derivatives containing 7-chloro-6-fluoro-N(substituted hydrozones- benzothiazole.Structures of compounds have been established by means of IR, 1H-NMR and elemental analysis. All the compounds were evaluated foe antibacterial, antifungal and antitubercular activities. Most of the compounds have shown significant antibacterial, antifungal and antitubercular activity when compared with the standard drug.

Dr. S. M. Hipparagi

2010-05-01

37

N-substituted 2-isonicotinoylhydrazinecarboxamides--new antimycobacterial active molecules.  

Science.gov (United States)

This report presents a new modification of the isoniazid (INH) structure linked with different anilines via a carbonyl group obtained by two synthetic procedures and with N-substituted 5-(pyridine-4-yl)-1,3,4-oxadiazole-2-amines prepared by their cyclisation. All synthesised derivatives were characterised by IR, NMR, MS and elemental analyses and were evaluated in vitro for their antimycobacterial activity against Mycobacterium tuberculosis H37Rv, Mycobacterium avium 330/88, Mycobacterium kansasii 235/80 and one clinical isolated strain of M. kansasii 6509/96. 2-Isonicotinoyl-N-(4-octylphenyl)hydrazinecarboxamide displayed an in vitro efficacy comparable to that of INH for M. tuberculosis with minimum inhibitory concentrations (MICs) of 1-2 ?M. Among the halogenated derivatives, the best anti-tuberculosis activity was found for 2-isonicotinoyl-N-(2,4,6-trichlorophenyl)hydrazinecarboxamide (MIC=4 ?M). In silico modelling on the enoyl-acyl carrier protein reductase InhA confirmed that longer alkyl substituents are advantageous for the interactions and affinity to InhA. Most of the hydrazinecarboxamides, especially those derived from 4-alkylanilines, exhibited significant activity against INH-resistant nontuberculous mycobacteria. PMID:24686575

Rychtar?kov, Zuzana; Krtk, Martin; Gazvoda, Martin; Komlov, Markta; Polanc, Slovenko; Ko?evar, Marijan; Stola?kov, Ji?ina; Vinov, Jarmila

2014-01-01

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N-Substituted 2-Isonicotinoylhydrazinecarboxamides New Antimycobacterial Active Molecules  

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Full Text Available This report presents a new modification of the isoniazid (INH structure linked with different anilines via a carbonyl group obtained by two synthetic procedures and with N-substituted 5-(pyridine-4-yl-1,3,4-oxadiazole-2-amines prepared by their cyclisation. All synthesised derivatives were characterised by IR, NMR, MS and elemental analyses and were evaluated in vitro for their antimycobacterial activity against Mycobacterium tuberculosis H37Rv, Mycobacterium avium 330/88, Mycobacterium kansasii 235/80 and one clinical isolated strain of M. kansasii 6509/96. 2-Isonicotinoyl-N-(4-octylphenylhydrazinecarboxamide displayed an in vitro efficacy comparable to that of INH for M. tuberculosis with minimum inhibitory concentrations (MICs of 12 ?M. Among the halogenated derivatives, the best anti-tuberculosis activity was found for 2-isonicotinoyl-N-(2,4,6-trichlorophenylhydrazinecarboxamide (MIC = 4 ?M. In silico modelling on the enoyl-acyl carrier protein reductase InhA confirmed that longer alkyl substituents are advantageous for the interactions and affinity to InhA. Most of the hydrazinecarboxamides, especially those derived from 4-alkylanilines, exhibited significant activity against INH-resistant nontuberculous mycobacteria.

Zuzana Rychtar?kov

2014-03-01

39

Novel N-substituted aminobenzamide scaffold derivatives targeting the dipeptidyl peptidase-IV enzyme  

Science.gov (United States)

Background The dipeptidyl peptidase-IV (DPP-IV) enzyme is considered a pivotal target for controlling normal blood sugar levels in the body. Incretins secreted in response to ingestion of meals enhance insulin release to the blood, and DPP-IV inactivates these incretins within a short period and stops their action. Inhibition of this enzyme escalates the action of incretins and induces more insulin to achieve better glucose control in diabetic patients. Thus, inhibition of this enzyme will lead to better control of blood sugar levels. Methods In this study, computer-aided drug design was used to help establish a novel N-substituted aminobenzamide scaffold as a potential inhibitor of DPP-IV. CDOCKER software available from Discovery Studio 3.5 was used to evaluate a series of designed compounds and assess their mode of binding to the active site of the DPP-IV enzyme. The designed compounds were synthesized and tested against a DPP-IV enzyme kit provided by Enzo Life Sciences. The synthesized compounds were characterized using proton and carbon nuclear magnetic resonance, mass spectrometry, infrared spectroscopy, and determination of melting point. Results Sixty-nine novel compounds having an N-aminobenzamide scaffold were prepared, with full characterization. Ten of these compounds showed more in vitro activity against DPP-IV than the reference compounds, with the most active compounds scoring 38% activity at 100 ?M concentration. Conclusion The N-aminobenzamide scaffold was shown in this study to be a valid scaffold for inhibiting the DPP-IV enzyme. Continuing work could unravel more active compounds possessing the same scaffold.

Al-Balas, Qosay A; Sowaileh, Munia F; Hassan, Mohammad A; Qandil, Amjad M; Alzoubi, Karem H; Mhaidat, Nizar M; Almaaytah, Ammar M; Khabour, Omar F

2014-01-01

40

Relaxation behavior in model compounds of poly(aryl-ether-ketone-ketone) as revealed by dielectric spectroscopy  

Science.gov (United States)

The relaxation behavior of a series of ether-ketone oligomers, considered as model compounds of poly(ether-ketone-ketone), was studied by means of dielectric spectroscopy. The dynamics of the ? relaxation of ether-ketone model compounds as compared with that of poly(arylether-ketone-ketone) (PEKK) (50/50), shows up differences which can be attributed to the variation of inter- and intramolecular correlations with the chain length. Model compounds exhibit a nearly similar degree of cooperativity regardless the differences in Tg values. The PEKK (50/50) polymer exhibits stronger cooperativity than the oligomers suggesting that in poly(ether-ketone-ketone)s molecular motions above Tg extend to more than one monomeric unit.

Ezquerra, T. A.; Zolotukhin, M.; Privalko, V. P.; Balt-Calleja, F. J.; Nequlqueo, G.; Garca, C.; de La Campa, J. G.; de Abajo, J.

1999-05-01

 
 
 
 
41

Thermolysis of Semicarbazones to the Corresponding Azines Through Reactive N-Substituted Isocyanate Intermediates  

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Full Text Available Thermolysis of semicarbazones (I to azines (II occurs through reactive N-substituted isocyanate intermediates (Ia which can be converted in situ to carbamates and Nsubstituted ureas.

N. K. Chudgar

2000-04-01

42

Modern Arylation Methods  

CERN Multimedia

Today, arylation methods are belonging to the most important reaction types in organic synthesis. Lutz Ackermann, a young and ambitious professor has gathered a number of top international authors to present the first comprehensive book on the topic. Starting from a historical review, the book covers hot topics like Palladium-catalyzed arylation of N-H and alpha-C-H-acidic Bonds, Copper-catalyzed arylation of N-H and O-H Bonds, direct arylation reactions, carbanion aromatic synthesis, arylation reactions of alkenes, alkynes and much more. This compact source of high quality information is indi

Ackermann, Lutz

2009-01-01

43

meso-Aryl triphyrin(2.1.1).  

Science.gov (United States)

Synthesis, spectral, and single-crystal X-ray structural analysis of meso-aryl triphyrin(2.1.1) featuring three pyrrole rings and four meso-aryl rings are described. The title compound represents the first example of a ring-contractedmeso-aryl ?-unsubstituted free-base triphyrin containing only pyrrole rings reported to date and generates 2-D supramolecular assembly in the solid state. PMID:21486086

Anju, K S; Ramakrishnan, S; Srinivasan, A

2011-05-01

44

MICROWAVE ASSISTED SYNTHESIS AND EVALUATION OF SOME FLUORO, CHLORO 2-N (SUBSTITUTED SCHIFFS BASES AMINO BENZOTHIAZOLES DERIVATIVES FOR THEIR ANTIINFLAMMATORY ACTIVITY  

Directory of Open Access Journals (Sweden)

Full Text Available The present research work is aimed to synthesize a series of various substituted benzothiazole derivatives containing 7-chloro-6-fluoro-N (substituted hydrozones - benzothiazole.Structures of compounds has been established by means of IR, 1H-NMR and elemental analysis. The compounds MIIIc, MIIIf and MIIIJ at dose 5 mg/kg and 10mg/kg body.wt were evaluated for anti-inflammatory activity using carragennan induced paw edema method. The selected compounds have shown significant anti-inflammatory activity as compared to the standard drug. Compound MIIIJ (10 mg/kg body weight has shown more significant result when compared with standard drug.

Muttu C.T

2010-12-01

45

Exploring the emissive properties of new azacrown compounds bearing aryl, furyl or thienyl moieties : a special case of chelation enhancement of fluorescence upon interaction with Ca2+, Cu2+ or Ni2+  

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Three new compounds bearing furyl, aryl or thienyl moieties linked to an imidazo-crown ether system (1, 2 and 3) were synthesized and fully characterized by elemental analysis, infrared, absorption and emission spectroscopy, X-ray crystal diffraction, and MALDI-TOF-MS spectrometry. The interaction towards metal ions (Ca2+, Cu2+, Ni2+ and Hg2+) and F- has been explored in solution by absorption and fluorescence spectroscopy. Mononuclear and binuclear metal complexes using Cu2+ or Hg2+ as metal...

2010-01-01

46

Transition Metal Catalyzed Synthesis of Aryl Sulfides  

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Full Text Available The presence of aryl sulfides in biologically active compounds has resulted in the development of new methods to form carbon-sulfur bonds. The synthesis of aryl sulfides via metal catalysis has significantly increased in recent years. Historically, thiolates and sulfides have been thought to plague catalyst activity in the presence of transition metals. Indeed, strong coordination of thiolates and thioethers to transition metals can often hinder catalytic activity; however, various catalysts are able to withstand catalyst deactivation and form aryl carbon-sulfur bonds in high-yielding transformations. This review discusses the metal-catalyzed arylation of thiols and the use of disulfides as metal-thiolate precursors for the formation of C-S bonds.

Chad C. Eichman

2011-01-01

47

Synthesis and Crystal Structures of N-Substituted Pyrazolines  

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Four pyrazole compounds, 3-(4-fluorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazole-1-carbaldehyde (1), 5-(4-bromophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazole-1-carbaldehyde (2), 1-[5-(4-chlorophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazol-1-yl]ethanone (3) and 1-[3-(4-fluorophenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl]propan-1-one (4), have been prepared by condensing chalcones with hydrazine hydrate in the presence of aliphatic acids, namely formic acid, acetic acid and propionic acid. Th...

Wan-Sin Loh; Ching Kheng Quah; Tze Shyang Chia; Hoong-Kun Fun; Majal Sapnakumari; Badiadka Narayana; Balladka Kunhanna Sarojini

2013-01-01

48

Heck-type coupling vs. conjugate addition in phosphine-rhodium catalyzed reactions of aryl boronic acids with alpha,beta-unsaturated carbonyl compounds: a systematic investigation.  

Science.gov (United States)

The competition between Heck-type coupling and conjugate addition in phosphine-rhodium catalyzed reactions of aryl boronic acids with alpha,beta-unsaturated carbonyls has been systematically investigated in a toluene-H(2)O biphasic system. Aside from the intrinsic nature of rhodium and the enolization of carbonyls, the phosphine supporting ligand on rhodium, the ratio of aryl boronic acid to alpha,beta-unsaturated carbonyl and the pH value of the aqueous phase were found to affect the competition significantly. Highly selective rhodium-based catalyst systems have therefore been developed for both Heck-type coupling and conjugate addition by synergistically tuning the supporting ligand, the boronic acid to olefin ratio and other reaction conditions. Conjugate addition with selectivity >99% and Heck-type coupling with selectivity of up to 100%, 98% and 84% for acrylates, acrylamides and methyl vinyl ketone, respectively, could be achieved in the rhodium-catalyzed reactions of aryl boronic acids with alpha,beta-unsaturated carbonyls using the corresponding optimized rhodium-based catalyst systems. PMID:17622423

Zou, Gang; Guo, Jianping; Wang, Zhiyong; Huang, Wen; Tang, Jie

2007-07-28

49

Synthesis of nanodispersible 6-aryl-2,4-diamino-1,3,5-triazine and its derivatives  

Energy Technology Data Exchange (ETDEWEB)

A series of novel branched derivatives of 6-aryl-2,4-diamino-1,3,5-triazine from corresponding aryl nitriles and dicyanodiamide was synthesized. These compounds show a nanodispersibility and good thermal stability.

Padalkar, Vikas S.; Patil, Vikas S.; Phatangare, Kiran R.; Gupta, Vinod D.; Umape, Prashant G. [Institute of Chemical Technology, Nathalal Parekh Marg, Matunga, Mumbai 400019 (India); Sekar, N., E-mail: n.sekar@ictmumbai.edu.in [Institute of Chemical Technology, Nathalal Parekh Marg, Matunga, Mumbai 400019 (India)

2010-06-15

50

Design, synthesis and evaluation of N-(substituted benzothiazol-2-yl)amides as anticonvulsant and neuroprotective.  

Science.gov (United States)

A series of N-(substituted benzothiazol-2-yl)amide derivatives 2a-h and 4a-h were synthesized by the EDC coupling reactions of substituted-benzothiazol-2-amine with 4-oxo-4-phenylbutanoic acid/2-benzoyl benzoic acid and evaluated for their anticonvulsant and neuroprotective effect. N-(6-methoxybenzothiazol-2-yl)-4-oxo-4-phenylbutanamide (2f) emerged as the most effective anticonvulsant with median doses of 40.96 mg/kg (MES ED(50)), 85.16 mg/kg (scPTZ ED(50)) and 347.6 mg/kg (TD(50)). Furthermore, compound 2f displayed promising neuroprotective effect by lowering the levels of MDA and LDH; therefore, it represents a potential lead in search for safer and effective anticonvulsants having neuroprotective effects. PMID:23124217

Hassan, Mohd Zaheen; Khan, Suroor A; Amir, Mohd

2012-12-01

51

?-Alkyl and ?-aryl complexes  

International Nuclear Information System (INIS)

Methods of preparation, solubility, reactivity, as well as molecular and crystal structure of ?-alkyl and ?-aryl complexes of rare earths of different composition are described. Di- and trisubstituted alkyl (aryl)lanthanides, their halogen derivatives of RLnHal type, afe-complexes, complexes of Cp2LnR type and ilide derivatives are considered in particular. 173 refs.; 17 figs.; 12 tabs

1989-01-01

52

Influence of some novel N-substituted azoles and pyridines on rat hepatic CYP3A activity.  

Science.gov (United States)

A series of N-substituted heteroaromatic compounds structurally related to clotrimazole was synthesized, and the effects of these compounds on ethosuximide clearance in rats were determined as a measure of their abilities to induce cytochrome P4503A (CYP3A) activity. Ethosuximide clearance and in vitro erythromycin N-demethylase activity were shown to correlate. In this series, imidazole or other related heteroaromatic "head groups" were linked to triphenylmethane or other phenylmethane derivatives. Within the series, it was found that 1-triphenylmethane-substituted imidazoles elicited the greatest increase in CYP3A activity, and that among the triphenylmethyl-substituted imidazoles, the highest activities were achieved by the substitution of F- or Cl- in either the meta or para position of one of the phenyl rings. Diphenylmethyl-substituted pyridine was effectively devoid of activity. Compounds eliciting the largest increase in CYP3A activity (viz. 1-[(3-fluorophenyl)diphenylmethyl]imidazole, 1-[(4-fluorophenyl)diphenylmethyl]imidazole, and 1-[tri-(4-fluorophenyl)methyl]imidazole) produced little or no increase in ethoxyresorufin O-dealkylase (EROD) activity (i.e. CYP1A), whereas benzylimidazole, which elicited only a small increase in CYP3A activity, produced an almost 9-fold increase in CYP1A activity. For a series of eleven compounds exhibiting a wide range of influence on CYP3A activity, a positive correlation was found between ethosuximide clearance and hepatic CYP3A mRNA levels. PMID:9714307

Slama, J T; Hancock, J L; Rho, T; Sambucetti, L; Bachmann, K A

1998-06-01

53

Comparative cytotoxicity of N-substituted N'-(4-imidazole-ethyl)thiourea in precision-cut rat liver slices  

International Nuclear Information System (INIS)

In order to more rationally design thiourea-containing drugs and drug candidates, specifically thiourea-containing histamine H3 receptor antagonists, it is necessary to develop structure-toxicity relationships (STRs). For this purpose, the cytotoxicity of a series of thiourea-containing compounds was tested in precision-cut rat liver slices. A concentration of 1000 ?M of N-p-bromophenyl, N'-(4-imidazole-ethyl)thiourea (8) or N-p-nitrophenyl, N'-(4-imidazole-ethyl)thiourea (9) was found to cause cytotoxicity, evidenced as LDH leakage, resulting in more than 95% LDH leakage after 6 h. N-p-Methoxyphenyl, N'-(4-imidazole-ethyl)thiourea (6) caused 40.619.7% LDH leakage after 6 h. Control levels of cell death (1% methanol as control vehicle) were below 20% in 6 h. After 6 h of exposure, N-p-chlorophenyl, N'-(4-imidazole-ethyl)thiourea (7), 8, and 9 were already found to cause significant cytotoxicity at a concentration of 100 ?M. At 200 ?M, 9 was found to cause significantly more cytotoxicity than 7 and 8. N-Naphthyl, N'-(4-imidazole-ethyl)thiourea (12) was found to cause significant cytotoxicity towards precision-cut rat liver slices after 6 h of exposure to a concentration of 500 ?M. All other N-substituted, N'-(4-imidazole-ethyl)thiourea tested in this study were not found to be cytotoxic towards precision-cut rat liver slices within the 6 h of exposure up to a concentration of 1000 ?M. Intracellular glutathione (GSH) content and mitochondrial MTT reduction activity were also examined after exposure of slices to N-substituted, N'-(4-imidazole-ethyl)thiourea. Both of these markers, however, were not found to provide additional information regarding the possible mechanisms of cytotoxicity, i.e. GSH depletion or reduced mitochondrial activity since these markers did not clearly precede LDH leakage. A correlation was found between cytotoxicity towards precision-cut rat liver slices and Vmax/Km values for the formation of sulfenic acids from N-substituted N'-(4-imidazole-ethyl)thiourea by hepatic rat flavin-containing monooxygenases (FMO). The compound with the highest Vmax/Km value for the formation of sulfenic acids, 9, was also the most cytotoxic. Compounds with a significantly lower Vmax/Km value, 7, 8, and 12, were less cytotoxic than 9. Compounds with a Vmax/Km value for the formation of sulfenic acids lower than 0.0788 ml/(min mg) were found not to be cytotoxic towards precision-cut rat liver slices for concentrations up to 1000 ?M at an exposure time of 6 h. It is concluded, from this study, that N-phenyl substituted N'-(4-imidazole-ethyl)thiourea-containing electron-withdrawing p-substituents are cytotoxic towards precision-cut rat liver slices. Cytotoxicity is increased with increasing electron-withdrawing capacity of the p-substituent. A correlation was found to exist between Vmax/Km value for the formation of sulfenic acids by rat liver FMO enzymes and cytotoxicity

2004-04-15

54

DFT Study of Oxygen Reduction Reaction on N-substituted Carbon Electrodes. Adsorption  

Energy Technology Data Exchange (ETDEWEB)

Carbon alloys attract attention as metal-free cathode catalysts. Mechanisms of oxygen reduction reactions are investigated using the DFT calculations and molecular models such as N-substituted coronene, circum pyrene, and corannulene. The overall oxygen reduction reaction (ORR) is decomposed into five elementary reactions. Adsorption of O{sub 2} is important as the first step of reduction, and it depends strongly on the spin density on C atoms, introduced by the N atom. Secondly the peripheral C atoms have an advantage due to the rehybridization freedom to the sp{sup 3} configuration. Based on the reversible electrode potential (REP) for each elementary reaction, the overpotential is expected for the first reduction of O{sub 2} to OOH and the final reduction of OH to H{sup 2}O. These features indicate that N-substituted carbon electrode resembles Pt electrode compared to other less active metals, such as Au.

Kobayashi, Hisayoshi; Tomoya, Nakzono; Miyazaki, Soichi; Miura, Toshiko; Takeuchi, Nobuyuki [Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Yamabe, Tokio, E-mail: kobayashi@chem.kit.ac.jp [Nagasaki Institute of Applied Science, 536, Amibacho, Nagasaki 851-0123 (Japan)

2011-05-15

55

DFT Study of Oxygen Reduction Reaction on N-substituted Carbon Electrodes. Adsorption  

International Nuclear Information System (INIS)

Carbon alloys attract attention as metal-free cathode catalysts. Mechanisms of oxygen reduction reactions are investigated using the DFT calculations and molecular models such as N-substituted coronene, circum pyrene, and corannulene. The overall oxygen reduction reaction (ORR) is decomposed into five elementary reactions. Adsorption of O2 is important as the first step of reduction, and it depends strongly on the spin density on C atoms, introduced by the N atom. Secondly the peripheral C atoms have an advantage due to the rehybridization freedom to the sp3 configuration. Based on the reversible electrode potential (REP) for each elementary reaction, the overpotential is expected for the first reduction of O2 to OOH and the final reduction of OH to H2O. These features indicate that N-substituted carbon electrode resembles Pt electrode compared to other less active metals, such as Au.

2011-05-01

56

Synthesis and characterization of thermoresponsive polymers, hydrogels and microgels, based on poly(N-substituted acrylamides)  

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Stimuli-responsive polymers have the unique property of undergoing a reversible phase transition. This property has attracted much interest for their application in the field of medicine and biotechnology, such as drug delivery systems. Linear polymers of the poly(N-substituted acrylamides) family and their three-dimensional macroscopic (hydrogels) or microscopic (microgels) networks demonstrate such a phase transition behavior. In particular, polymers of this family have the ability to respo...

2004-01-01

57

Design, Synthesis, and Evaluation of 10-N-Substituted Acridones as Novel Chemosensitizers in Plasmodium falciparum?  

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A series of novel 10-N-substituted acridones, bearing alkyl side chains with tertiary amine groups at the terminal position, were designed, synthesized, and evaluated for the ability to enhance the potency of quinoline drugs against multidrug-resistant (MDR) Plasmodium falciparum malaria parasites. A number of acridone derivatives, with side chains bridged three or more carbon atoms apart between the ring nitrogen and terminal nitrogen, demonstrated chloroquine (CQ)-chemosensitizing activity ...

Kelly, Jane X.; Smilkstein, Martin J.; Cooper, Roland A.; Lane, Kristin D.; Johnson, Robert A.; Janowsky, Aaron; Dodean, Rozalia A.; Hinrichs, David J.; Winter, Rolf; Riscoe, Michael

2007-01-01

58

N-substituted aminomethanephosphonic and aminomethane-P-methylphosphinic acids as inhibitors of ureases  

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Small unextended molecules based on the diamidophosphate structure with a covalent carbon-to-phosphorus bond to improve hydrolytic stability were developed as a novel group of inhibitors to control microbial urea decomposition. Applying a structure-based inhibitor design approach using available crystal structures of bacterial urease, N-substituted derivatives of aminomethylphosphonic and P-methyl-aminomethylphosphinic acids were designed and synthesized. In inhibition studies using urease fr...

Berlicki, ?ukasz; Bochno, Marta; Grabowiecka, Agnieszka; Bia?as, Arkadiusz; Kosikowska, Paulina; Kafarski, Pawe?

2012-01-01

59

Experimental and computational studies on the tautomerism of N-substituted 3-amino-5-oxo-4-phenyl-1H-pyrazolo-1-carboxamides with antibacterial activity  

Science.gov (United States)

The tautomerism of N-substituted 3-amino-5-oxo-4-phenyl-1H-pyrazolo-1-carboxamides with antibacterial activity is studied with X-ray crystallography, IR, 1H and 13C NMR (including NOESY spectra) and quantum chemical calculations. It is found that the form with the keto group at position 5 is the preferred one in the crystalline state and in DMSO, although some fraction with the corresponding hydroxy group also occurs in both states. This finding was related to the antibacterial activity of the studied compounds as the energetic stabilization of the keto group may determine their proper hydrogen bond interactions with the bacterial enzyme.

Kaczor, Agnieszka A.; Wrbel, Tomasz; Karczmarzyk, Zbigniew; Wysocki, Waldemar; Mendyk, Ewaryst; Poso, Antti; Matosiuk, Dariusz; Pitucha, Monika

2013-11-01

60

Substituent and structural effects on the kinetics of the reaction of N-(substituted phenylmethylene-m- and -p-aminobenzoic acids with diazodiphenylmethane  

Directory of Open Access Journals (Sweden)

Full Text Available The rate constants for the reaction of twenty-two N-(substituted phenyl methylene-m- and -p-aminobenzoic acids with diazodiphenylmethane were determined in absolute ethanol at 30 C. The effects of substituents on the reactivity of the investigated compounds were interpreted by correlation of the rate constants with LFER equations. The results of quantum mechanical calculations of the mole cular structure together with experimental results gave a better insight into the effects of structure on the transmission of electronic effects of the substituents. New ? constants for substituted benzylideneamino group were calculated.

BRATISLAV Z. JOVANOVIC

2007-12-01

 
 
 
 
61

Synthesis and acetylcholinesterase (AChE inhibitory activity of some N -substituted-5-chloro-2(3 H - benzoxazolone derivatives  

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Full Text Available Alzheimers disease is a progressive neurodegenerative disorder of the central nervous system. Acetylcholinesterase inhibition is one of the proposed mechanisms for treatment of Alzheimers disease. Currently, acetylcholinesterase inhibitors such as tacrine,donepezil, rivastigmine and galantamine are applied in different stages of Alzheimers disease teratment. In recent years, various heterocyclic systems have been used as a skeletonto discover new acetylcholinesterase inhibitors. On the other hand, it is known that the benzoxazolone heterocyclic structure exhibited a wide range of biological activities. In this study, a seriesN-substituted-5-chloro-2(3H-benzoxazolone derivatives were synthesized and evaluated their acetylcholinesterase inhibitory activity. These compounds were synthesized by Mannich reaction of 5-chloro-2(3H-benzoxazolone with the appropriated amines.The acetylcholinesterase inhibitory activity of the title compounds was determined by colorimetric Ellmans method. The preliminary screening results indicated that 5-chloro-2-(3H-benzoxazolone scaffold demonstrated different inhibition range againstacetylcholinesterase enzyme depending on the structural differences

Zeynep Soyer

2013-01-01

62

Crystallographic characterization of single-ortho, N-substituted acetanilide derivatives  

International Nuclear Information System (INIS)

The crystal and molecular structures of the three single-ortho, N-substituted amide derivatives, acet-2'-bromo-N-(p-nitrobenzyl)anilide, 3',5'-dimethyl-N-ethyl-2,2,2',4'-tetrachlorobenzoylacetanilide, and difluoro[(1-phenyl-2-(o-ethylphenyl-N-benzylcarbamoyl)vinyl)oxy]borane, have been determined by X-ray diffraction analysis. In each case, the amide carbonyl group was found in the exo-conformation, independent of the nature of the acyl group. The observed conformations correlate well with solution structures, inferred from n.m.r. data

1987-01-01

63

Stability constants of complexes of the N-substituted anthranilic acids with lanthanides  

International Nuclear Information System (INIS)

The interaction between trivalent metal ions La(III), Pr(III), Nd(III), Gd(III), Dy(III) and Y(III) with N-substituted anthranilic acids have been studied in 50 per cent ethanol-water medium at various ionic strengths and at constant temperature, following potentiometric technique. The order of stability constants with respect to metal ions has been found to be La N-Me. An. A. > N-Et. An. A > N-Ph.An. A. (author). 2 tabs., 11 refs

1988-01-01

64

Green and selective synthesis of N-substituted amides using water soluble porphyrazinato copper(II) catalyst  

International Nuclear Information System (INIS)

N, N',N, N'-Tetramethyl tetra-2,3-pyridinoporphyrazinato copper(II) methyl sulfate ([Cu(2,3-tmtppa)](MeSO4)4) efficiently catalyzed the direct conversion of nitriles to N-substituted amides. The one pot selective synthesis of the N-substituted amides from nitriles and primary amines was performed in refluxing H2O. The catalyst was recovered and reused at least four times, maintaining its efficiency. (author)

2013-06-01

65

Inorganic base-catalyzed formation of antivirally active N-substituted benzamides from ?-amido sulfones and N-nucleophile  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Heteronucleophiles as well as carbanionic reagents can be used to react with ?-amido sulfones, thus giving the opportunity to prepare a large array of amino derivatives. Since, novel 1,3,4-oxadiazole-2-thiol derivatives can serve as potent nucleophiles, we employed 5-subsititued phenyl-1,3,4-oxadiazole-2-thiols as the nucleophilic source of nitrogen in the reaction with ?-amido sulfones. Results A series of N-substituted benzamides bearing 1,3,4-oxadiazol unit were prepared for the first time by the reaction of in situ generated protected imine from ?-amido sulfones with 5-subsititued phenyl-1,3,4-oxadiazole-2-thiols as the source of nitrogen nucleophile. Some of the synthesized products displayed favourable antiviral activity against cucumber mosaic virus (CMV in preliminary antiviral activity tests. The title compounds 5c, 5o and 5r revealed curative activity of 42.2%, 48.7% and 40.5%, respectively against CMV (inhibitory rate compared to the commercial standard Ningnanmycin (53.4% at 500 ?g/mL. Conclusion A practical synthetic route to N-benzoyl-?-amido sulfones by the reaction of 5-subsititued phenyl-1,3,4-oxadiazole-2-thiols as the source of nitrogen nucleophiles with in situ generated protected imine from N-benzoyl-?-amido sulfones is presented. The reaction catalyzed by an inorganic base has considerable significance to exploit the potential of ?-amido sulfones in organic synthesis.

Wang Zhenchao

2011-05-01

66

Novel compound 2-methyl-2H-pyrazole-3-carboxylic acid (2-methyl-4-o-tolylazo-phenyl)-amide (CH-223191) prevents 2,3,7,8-TCDD-induced toxicity by antagonizing the aryl hydrocarbon receptor.  

Science.gov (United States)

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a widespread environmental pollutant with many toxic effects, including endocrine disruption, reproductive dysfunction, immunotoxicity, liver damage, and cancer. These are mediated by TCDD binding to and activating the aryl hydrocarbon receptor (AhR), a basic helix-loop-helix transcription factor. In this regard, targeting the AhR using novel small molecule inhibitors is an attractive strategy for the development of potential preventive agents. In this study, by screening a chemical library composed of approximately 10,000 compounds, we identified a novel compound, 2-methyl-2H-pyrazole-3-carboxylic acid (2-methyl-4-o-tolylazo-phenyl)-amide (CH-223191), that potently inhibits TCDD-induced AhR-dependent transcription. In addition, CH-223191 blocked the binding of TCDD to AhR and inhibited TCDD-mediated nuclear translocation and DNA binding of AhR. These inhibitory effects of CH-223191 prevented the expression of cytochrome P450 enzymes, target genes of the AhR. Unlike many known antagonists of AhR, CH-223191 did not have detectable AhR agonist-like activity or estrogenic potency, suggesting that CH-223191 is a specific antagonist of AhR. It is noteworthy that CH-223191 potently prevented TCDD-elicited cytochrome P450 induction, liver toxicity, and wasting syndrome in mice. Taken together, these results demonstrate that this novel compound, CH-223191, may be a useful agent for the study of AhR-mediated signal transduction and the prevention of TCDD-associated pathology. PMID:16540597

Kim, Sun-Hee; Henry, Ellen C; Kim, Dong-Kyu; Kim, Yun-Hee; Shin, Kum Joo; Han, Myoung Sook; Lee, Taehoon G; Kang, Jong-Ku; Gasiewicz, Thomas A; Ryu, Sung Ho; Suh, Pann-Ghill

2006-06-01

67

Efficient copper-catalyzed N-arylation of sulfoximines with aryl iodides and aryl bromides.  

Science.gov (United States)

Two simple and inexpensive systems for copper-catalyzed N-arylations of sulfoximines with aryl bromides and aryl iodides have been developed. Using 10 mol % of a copper(I) salt in combination with 20 mol % of a 1,2-diamine and Cs2CO3 provides N-arylated sulfoximines in high yields. Various functional groups and heteroatoms are tolerated. The method is complementary to the known protocols for N-arylations of sulfoximines, which require stoichiometric quantities of copper salts or cost-intensive palladium/BINAP catalysts. PMID:16095312

Sedelmeier, Jrg; Bolm, Carsten

2005-08-19

68

Synthesis, growth and characterization of new 1,3,4 -thiadiazole-5-(n-substituted)-sulfonamides cristals  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in spanish Nuevas 1,3,4-tiadiazol-5-(N-substituidas)-sulfonamidas, inhibidores de anhidrasa carbnica, fueron obtenidas incorporando los grupos N-ciclohexil, N-benzil and N-[sec-butil], por una sntesis optimizada y monocristales de las mismas fueron crecidos desde alcohol absoluto por evaporacin lenta a temp [...] eratura ambiente hasta dimensiones adecuadas para medidas de DRX. Los datos estructurales de estos compuestos monoclnicos son comparados con los de otras fases relacionadas. El grupo sulfonil presenta una geometra tetradrica distorsionada alrededor del tomo de S. Los diferentes sustituyentes introducidos no producen modificaciones en la estructura del anillo 1,3,4-tiadiazol. El anlisis trmico de las tres fases muestra descomposicin total a temperaturas por encima del punto de fusin. Los espectros FTIR confirman la formacin de los compuestos y es el primer aporte sobre el conocimiento de la unin puente hidrgeno NH...N en estas sulfonamidas. Abstract in english New 1,3,4-thiadiazole-5-(N-substituted)-sulfonamide derivatives incorporating N-cyclohexyl, N-benzyl and N-[sec-butyl] moieties, carbonic anhydrase inhibitors, have been obtained by an optimized synthesis. Single crystals of these sulfonamides have been successfully grown up to suitable dimensions f [...] or X-ray diffraction measurements by slow evaporation of solvent at room temperature. Structural data for these monoclinic compounds are compared with those of related phases. The sulfonyl moiety presents a distorted tetrahedral arrangement around the S atom. The different groups introduced cause no observable modifications of the 1,3,4-thiadiazole ring structure. Thermal analysis show total sample degradation at temperatures higher than that of the melting point of the three phases. The FTIR spectra confirm the compounds formation and provide a first insight on the modes of NHN hydrogen bond in these sulfonamides.

G.E., Cam; M.del C., Ramrez de Arellano; S., Fustero; J.C., Pedregosa.

69

Palladium-catalyzed aryl amination-heck cyclization cascade: A one-flask approach to 3-substituted Indoles  

DEFF Research Database (Denmark)

Two for the price of one: A Pd/dppf-based catalyst provides access to the title compounds from 1,2-dihalogenated aromatic compounds and allylic amines in a single reaction flask. The initial aryl amination step occurs with excellent selectivity for the aryl iodide to ensure the formation of a single indole regioisomer, which can be functionalized in situ by N-arylation (see scheme).

Jensen, Thomas; Pedersen, Henrik

2008-01-01

70

C-Arylation reactions catalyzed by CuO-nanoparticles under ligand free conditions  

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Full Text Available CuO-nanoparticles were found to be an excellent heterogeneous catalyst for C-arylation of active methylene compounds using various aryl halides. The products were obtained in good to excellent yield. The catalyst can be recovered and reused for four cycles with almost no loss in activity.

Mazaahir Kidwai

2010-04-01

71

Menthone aryl acid hydrazones: a new class of anticonvulsants.  

Science.gov (United States)

A series of ten compounds (Compounds J(1)-J(10)) of () 3-menthone aryl acid hydrazone was synthesized and characterized by thin layer chromatography and spectral analysis. Synthesized compounds were evaluated for anticonvulsant activity after intraperitoneal (i.p) administration to mice by maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) induced seizure method and minimal clonic seizure test. Minimal motor impairment was also determined for these compounds. Results obtained showed that four compounds out of ten afforded significant protection in the minimal clonic seizure screen at 6 Hz. Compound J(6), 4-Chloro-N-(2-isopropyl-5-methylcyclohexylidene) benzohydrazide was found to be the most active compound with MES ED(50) of 16.1 mg/kg and protective index (pI) of greater than 20, indicating that () 3-menthone aryl acid hydrazone possesses better and safer anticonvulsant properties than other reported menthone derivatives viz. menthone Schiff bases, menthone semicarbazides and thiosemicarbazides. PMID:21235520

Jain, Jainendra; Kumar, Y; Sinha, Reema; Kumar, Rajeev; Stables, James

2011-01-01

72

Synthesis and characterization of methacrylamidopropyltrimethylammonium chloride and N-substituted acrylamide ionomers  

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Full Text Available Quaternary ammonium ionomers of Methacrylamidopropyltrimethyl ammonium chloride with N-substituted acrylamides were prepared at 551C using azobiscyanovaleric acid (ACVA initiator. The monomers and ionomers were characterized by 1H- and 13C-NMR spectroscopy and the copolymer composition was calculated from elemental analysis data. The reduced viscosity of ionomers in methanol behaves as non-polyelectrolytes at lower mole percentage and as polyelectrolyte at higher mole percentage. The molecular weights of ionomers were found to be high and the polydispersity index values indicate termination mainly by disproportionation. The glass transition temperature (Tg of ionomers were greater than those of the corresponding homopolymers, attributed to a reduction in segmental mobility. The initial decomposition temperature (IDT showed that the stability of ionomers increases with increasing mole percentage of ionic content.

2007-11-01

73

Solid-Phase Synthesis of N-Substituted Glycine Oligomers (??Peptoids and Derivatives  

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Full Text Available Peptoids (N-substituted polyglycines and extended peptoids with variant backbone amino-acid monomer units are oligomeric synthetic polymers that are becoming a valuable molecular tool in the biosciences. Of particular interest are their applications to the exploration of peptoid secondary structures and drug design. Major advantages of peptoids as research and pharmaceutical tools include the ease and economy of synthesis, highly variable backbone and side-chain chemistry possibilities. At the same time, peptoids have been demonstrated as highly active in biological systems while resistant to proteolytic decay. This review with 227 references considers the solid-phase synthetic aspects of peptoid preparation and utilization up to 2010 from the instigation, by R. N. Zuckermann et al., of peptoid chemistry in 1992.

Rodney J. Ouellette

2010-08-01

74

Some higher N-substituted 1,3-thiazolidine-2,4-diones and 5,5-diphenylhydantoins, their synthesis and corrosion preventive properties in mineral oil medium  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer N-substituted 5,5-diphenylhydantoins and 1,3-thiazolidine-2,4-diones were prepared. Black-Right-Pointing-Pointer All synthesized compounds showed good inhibition effect in oil-water medium. Black-Right-Pointing-Pointer The test results were supported with water contact angle measurements and with SEM. Black-Right-Pointing-Pointer Inhibition effect of compounds were evidenced by the optical profilometer photos. - Abstract: Some five membered heterocyclic compounds were synthesized by the reaction of 2,4-thiazolidinedione or 5,5-diphenylhydantoin potassium salts with 2-chloro-N-alkylacetamides and alkyl-2-chloroacetates. The structure confirmations of the synthesized compounds were performed by FT-IR, {sup 1}H NMR, {sup 13}C NMR spectra. The inhibitory effectiveness of the compounds were evaluated against the corrosion of steel strip immersed in water containing paraffin based mineral oil medium in accordance to standard test method. Surface characterization studies of the metal coupons used were performed by SEM analysis and also by the contact angle measurements using the Sessile-Drop method. In addition the 3D image of the metal surface was obtained using optical profilometer. The test results and surface characterization studies showed that all synthesized compounds are excellent corrosion inhibitors in such a water in oil emulsion system.

Oeztuerk, Serkan, E-mail: serkanozturk@uludag.edu.tr [Department of Chemistry, Faculty of Science and Arts, Uludag University, 16059 Bursa (Turkey); Y Latin-Small-Letter-Dotless-I ld Latin-Small-Letter-Dotless-I r Latin-Small-Letter-Dotless-I m, Ayhan; Cetin, Mehmet [Department of Chemistry, Faculty of Science and Arts, Uludag University, 16059 Bursa (Turkey)

2013-01-15

75

Direct N(9)-arylation of purines with aryl halides.  

Science.gov (United States)

An efficient method for N-arylation of purines is reported. The N-arylation is catalysed by Cu(i) and 4,7-bis(2-hydroxyethylamino)-1,10-phenanthroline (BHPhen) in aqueous DMF or ethanol. The reaction generally proceeds with high selectivity for the N(9)-position. PMID:24579090

Larsen, Anders Foller; Ulven, Trond

2014-04-17

76

Green and selective synthesis of N-substituted amides using water soluble porphyrazinato copper(II) catalyst  

Energy Technology Data Exchange (ETDEWEB)

N, N',N{sup ,} N{sup '}-Tetramethyl tetra-2,3-pyridinoporphyrazinato copper(II) methyl sulfate ([Cu(2,3-tmtppa)](MeSO{sub 4}){sub 4}) efficiently catalyzed the direct conversion of nitriles to N-substituted amides. The one pot selective synthesis of the N-substituted amides from nitriles and primary amines was performed in refluxing H{sub 2}O. The catalyst was recovered and reused at least four times, maintaining its efficiency. (author)

Ghodsinia, Sara S.E.; Akhlaghinia, Batool; Eshghi, Hossein, E-mail: akhlaghinia@um.ac.ir [Ferdowsi University of Mashhad (Iran, Islamic Republic of). Faculty of Sciences. Department of Chemistry; Safaei, Elham [Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan (Iran, Islamic Republic of). Department of Chemistry

2013-06-15

77

Synthesis of N-substituted ?-hexonolactams as pharmacological chaperones for the treatment of N370S mutant Gaucher disease.  

Science.gov (United States)

A series of N-substituted ?-hexonolactams have been designed and prepared by a concise route with a tandem ring-expansion reaction as the key step. Some of the N-substituted ?-hexonolactams show better enhancements to N370S mutant ?-glucocerebrosidase activity than NB-DNJ and NN-DNJ. Both the experimental results and computational studies highlight the importance of the carbonyl group for stabilizing protein folds in the mutant enzyme. The structure-activity relationships are also discussed. These novel N-alkylated iminosugars are promising pharmacological chaperones for the treatment of N370S mutant Gaucher disease. PMID:22286559

Wang, Guan-Nan; Twigg, Gabriele; Butters, Terry D; Zhang, Siwei; Zhang, Liangren; Zhang, Li-He; Ye, Xin-Shan

2012-04-21

78

Synthesis, structure-activity relationship and biological evaluation of novel N-substituted matrinic acid derivatives as host heat-stress cognate 70 (Hsc70) down-regulators.  

Science.gov (United States)

Oxymatrine (1) is a natural anti-hepatitis B virus (HBV) drug that down-regulates host heat-stress cognate 70 (Hsc70) expression through a mechanism different from that of nucleosides. Taking Hsc70 as a target against HBV, 26 novel N-substituted matrinic acid analogs were designed, synthesized and evaluated for their regulation of Hsc70 mRNA expression with 1 as the lead. The SAR analysis revealed that (i) the carboxyl group at the 11-position was required for activity; (ii) introducing of a substituent on the nitrogen atom at the 12-position of 3, especially substituted benzyl, might significantly improve the activity. Among these analogs, compound 9p possessing N-p-methoxylbenzyl afforded an increased anti-HBV effect in comparison with 1. We consider 9p a promising anti-HBV candidate. PMID:21757347

Du, Na-Na; Li, Xin; Wang, Yu-Ping; Liu, Fei; Liu, Yan-Xin; Li, Chun-Xin; Peng, Zong-Gen; Gao, Li-Mei; Jiang, Jian-Dong; Song, Dan-Qing

2011-08-15

79

Palladium-catalyzed microwave-assisted direct arylation of imidazo[2,1-b]thiazoles with aryl bromides: synthesis and mechanistic study.  

Science.gov (United States)

A palladium-catalyzed direct C-H arylation of various imidazo[2,1-b]thiazoles with a range of aryl bromides under microwave irradiation is described. 6-Phenyl substituted imidazo[2,1-b]thiazoles could be regioselectively C-5 arylated using the developed protocol. The utility of this method enables the representative coupling product to be achieved by a sequential one-pot reaction. Density functional theory (DFT) calculations show that this arylation proceeds via a concerted metalation-deprotonation (CMD) pathway, which is in agreement with our experimental results. This work provides a convenient access to a variety of biologically active imidazo[2,1-b]thiazole derivatives. Also, it enriches the mechanism study of site-selective C-H arylation in fused heterocycles, and offers a valuable guide to design highly efficient catalytic systems for the preparation of similar compounds. PMID:24976187

Zhu, Yi-Shuo; Shi, Benyi; Fang, Ran; Wang, Xiaoxuan; Jing, Huanwang

2014-08-14

80

A new class of anticonvulsants possessing 6 Hz psychomotor seizure test activity: 2-(1H-benzotriazol-1-yl)-N'-[substituted] acetohydrazides.  

Science.gov (United States)

A series of 2-(1H-Benzotriazol-1-yl)-N'-[substituted]acetohydrazides were designed & synthesized keeping in view the structural requirement of pharmacophore and evaluated for anticonvulsant activity and neurotoxicity. The new compounds were characterized using FT-IR, 1H NMR, mass spectral data and elemental analysis. The anticonvulsant activity of the titled compounds was assessed using the 6 Hz psychomotor seizure test. The neurotoxicity was assessed using the rotorod method. The most active compound of the series was N'-[4-(1,3-Benzodioxol-5-yloxy)benzylidene]-2-(1H-benzotriazol-1-yl)acetohydrazide (BTA 9), which showed good activity with 75 % protection (3/4, 0.5 h) at a dose of 100 mg/kg in mice. All the compounds exhibited no neurotoxicity. A computational study was carried out for calculation of pharmacophore pattern and prediction of pharmacokinetic properties. Titled compounds have also exhibited good binding properties with epilepsy molecular targets such as glutamate, GABA (A) delta, GABA (A) alpha-1 receptors and Na/H exchanger, in Lamarckian genetic algorithm based flexible docking studies. PMID:22530911

Kumar, Praveen; Tripathi, Laxmi

2012-05-01

 
 
 
 
81

Synthesis, Characterization and Properties of Stable Chromium (III) Aryl Isocyanide Complexes.  

Science.gov (United States)

The chemistry of homoleptic isocyanide complexes of chromium has been of interest to organometallic chemists since the synthesis of the zerovalent hexacoordinate aryl iso-cyanide derivatives. These compounds have been the subject to several electrochemica...

D. A. Bohling K. R. Mann

1983-01-01

82

The essential role of the electronegativity perturbation in vibronic interactions in positively charged B,N-substituted acenes  

Energy Technology Data Exchange (ETDEWEB)

Total electron-phonon coupling constants for the monocations (l {sub HOMO}) of B,N-substituted acene-series such as B{sub 3}N{sub 3}H{sub 6}, B{sub 5}N{sub 5}H{sub 8}, and B{sub 7}N{sub 7}H{sub 10} are estimated. The estimated l {sub HOMO} values of 0.357, 0.209, and 0.182 eV for B{sub 3}N{sub 3}H{sub 6}, B{sub 5}N{sub 5}H{sub 8}, and B{sub 7}N{sub 7}H{sub 10}, respectively, are larger than those of 0.244, 0.173, and 0.130 eV for benzene, naphthalene, and anthracene, respectively. Furthermore, the l {sub HOMO} value for B,N-substituted polyacene (0.096 eV) is estimated to be larger than that for polyacene (0.036 eV). Stronger orbital interactions between B and N atoms in the highest occupied molecular orbitals (HOMO) in B,N-substituted acene-series than those between two neighboring carbon atoms in the HOMO in acene-series as a consequence of electronegativity perturbation on acene-series, are the main reason why the l {sub HOMO} values for B,N-substituted acene-series are larger than those for acene-series.

Kato, Takashi [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano-Nishihiraki-cho, Sakyo-ku, Kyoto 606-8103 (Japan); Institute for Innovative Science and Technology, Graduate School of Engineering, Nagasaki Institute of Applied Science, 536, Aba-machi, Nagasaki 851-0193 (Japan)], E-mail: kato@cc.nias.ac.jp; Yamabe, Tokio [Institute for Innovative Science and Technology, Graduate School of Engineering, Nagasaki Institute of Applied Science, 536, Aba-machi, Nagasaki 851-0193 (Japan)

2005-08-08

83

The essential role of the electronegativity perturbation in vibronic interactions in positively charged B,N-substituted acenes  

International Nuclear Information System (INIS)

Total electron-phonon coupling constants for the monocations (l HOMO) of B,N-substituted acene-series such as B3N3H6, B5N5H8, and B7N7H10 are estimated. The estimated l HOMO values of 0.357, 0.209, and 0.182 eV for B3N3H6, B5N5H8, and B7N7H10, respectively, are larger than those of 0.244, 0.173, and 0.130 eV for benzene, naphthalene, and anthracene, respectively. Furthermore, the l HOMO value for B,N-substituted polyacene (0.096 eV) is estimated to be larger than that for polyacene (0.036 eV). Stronger orbital interactions between B and N atoms in the highest occupied molecular orbitals (HOMO) in B,N-substituted acene-series than those between two neighboring carbon atoms in the HOMO in acene-series as a consequence of electronegativity perturbation on acene-series, are the main reason why the l HOMO values for B,N-substituted acene-series are larger than those for acene-series

2005-08-08

84

Anaerobic biotransformation of roxarsone and related N-substituted phenylarsonic acids  

Science.gov (United States)

Large quantities of arsenic are introduced into the environment through land application of poultry litter containing the organoarsenical feed additive roxarsone (3-nitro-4-hydroxyphenylarsonic acid). The objective of this study was to evaluate the bioconversion of roxarsone and related N-substituted phenylarsonic acid derivatives under anaerobic conditions. The results demonstrate that roxarsone is rapidly transformed in the absence of oxygen to the corresponding aromatic amine, 4-hydroxy-3-aminophenylarsonic acid (HAPA). The formation of HAPA is attributable to the facile reduction of the nitro group. Electron-donating substrates, such as hydrogen gas, glucose, and lactate, stimulated the rate of nitro group reduction, indicating a microbial role. During long-term incubations, HAPA and the closely related 4-aminophenylarsonic acid (4-APA) were slowly biologically eliminated by up to 99% under methanogenic and sulfate-reducing conditions, whereas little or no removal occurred in heat-killed inoculum controls. Arsenite and, to a lesser extent, arsenate were observed as products of the degradation. Freely soluble forms of the inorganic arsenical species accounted for 19-28% of the amino-substituted phenylarsonic acids removed. This constitutes the first report of a biologically catalyzed rupture of the phenylarsonic group under anaerobic conditions. ?? 2006 American Chemical Society.

Cortinas, I.; Field, J. A.; Kopplin, M.; Garbarino, J. R.; Gandolfi, A. J.; Sierra-Alvarez, R.

2006-01-01

85

N-substituted aminomethanephosphonic and aminomethane-P-methylphosphinic acids as inhibitors of ureases.  

Science.gov (United States)

Small unextended molecules based on the diamidophosphate structure with a covalent carbon-to-phosphorus bond to improve hydrolytic stability were developed as a novel group of inhibitors to control microbial urea decomposition. Applying a structure-based inhibitor design approach using available crystal structures of bacterial urease, N-substituted derivatives of aminomethylphosphonic and P-methyl-aminomethylphosphinic acids were designed and synthesized. In inhibition studies using urease from Bacillus pasteurii and Canavalia ensiformis, the N,N-dimethyl derivatives of both lead structures were most effective with dissociation constants in the low micromolar range (Ki=130.8 and 0.620.09 ?M, respectively). Whole-cell studies on a ureolytic strain of Proteus mirabilis showed the high efficiency of N,N-dimethyl and N-methyl derivatives of aminomethane-P-methylphosphinic acids for urease inhibition in pathogenic bacteria. The high hydrolytic stability of selected inhibitors was confirmed over a period of 30 days using NMR technique. PMID:21559954

Berlicki, Lukasz; Bochno, Marta; Grabowiecka, Agnieszka; Bia?as, Arkadiusz; Kosikowska, Paulina; Kafarski, Pawe?

2012-05-01

86

Radioimmunoassay for anileridine, meperidine, and other N-substituted phenylpiperidine carboxylic acid esters  

Energy Technology Data Exchange (ETDEWEB)

Antibodies that bind an /sup 125/I-tyramyl derivative of N-succinylanileridine have been produced in animals immunized with N-succinylanileridine-hemocyanin conjugate. Several congeners and metabolites have been tested as competitors of this antigen-antibody reaction. The concentrations (in picomoles) required for 50 percent inhibition have been found to be: anileridine (0.2), meperidine (3.5), piminodine (3.8), diphenoxylate (20.5), normeperidine (20.0), meperidine acid (45,000) and anileridine acid (3,400). Although ester hydrolysis results in changes in inhibiting capacities on the order of 10/sup 4/, major structural changes in the substituent on the nitrogen of the piperidine ring are not readily recognized by the antibody. This radioimmunoassay can be used to study a variety of N-substituted phenylpiperidine carboxylic acid esters by relating the results to the standard curve obtained for the drug under investigation. For all practical purposes, alphaprodine, morphine and methadone do not interfere with the assay.

Van Vunakis, H.; Freeman, D.S.; Gjika, H.B.

1975-10-01

87

Radioimmunoassay for anileridine, meperidine, and other N-substituted phenylpiperidine carboxylic acid esters  

International Nuclear Information System (INIS)

Antibodies that bind an 125I-tyramyl derivative of N-succinylanileridine have been produced in animals immunized with N-succinylanileridine-hemocyanin conjugate. Several congeners and metabolites have been tested as competitors of this antigen-antibody reaction. The concentrations (in picomoles) required for 50 percent inhibition have been found to be: anileridine (0.2), meperidine (3.5), piminodine (3.8), diphenoxylate (20.5), normeperidine (20.0), meperidine acid (45,000) and anileridine acid (3,400). Although ester hydrolysis results in changes in inhibiting capacities on the order of 104, major structural changes in the substituent on the nitrogen of the piperidine ring are not readily recognized by the antibody. This radioimmunoassay can be used to study a variety of N-substituted phenylpiperidine carboxylic acid esters by relating the results to the standard curve obtained for the drug under investigation. For all practical purposes, alphaprodine, morphine and methadone do not interfere with the assay

1975-01-01

88

ON THE ANTIOXIDANT EFFECTIVENESS OF N,NSUBSTITUTED P-PHENYLENEDIAMINES  

Directory of Open Access Journals (Sweden)

Full Text Available The ground-state geometry of six N,N-substituted p-phenylenediamines (PPDs: N-phenyl-N-dimethyl-butyl-p-phenylenediamine (6PPD, N-phenyl-N-isopropyl-p-phenylenediamine (IPPD, N-phenyl-N-(?-methylbenzyl-p-phenylenediamine (SPPD, N-(2-methoxybenzyl-N-phenyl-p-phenylenediamine (MBPPD, N-benzyl-N-phenyl-p-phenylenediamine (MBPPDH, N-(1-methyl-1-phenylethyl-N-phenyl-p-phenylene-diamine (CPPD molecules, their radical structures and the energy characterisation of these molecules and radicals were theoretically investigated using PM3 method. Our calculations reveal the most probable radical formation in the order SPPD > MBPPD > MBPPDH > 6PPD > IPPD > CPPD. The theoretical values have been compared with the values obtained by the analysis of structural units contributions based on the results of non-isothermal DSC measurements. The results show that the most likely process is homolytic cleavage of CH bond at the carbon atom in the neighbourhood of the amino nitrogen atom and the sterical arrangement is related to the antioxidant effectiveness of the antioxidants under study. The suggested models can be used for the interpretation and prediction of experimental data what is important from the technological point of view.

Vladimr Luke

2004-10-01

89

Synthesis and antimicrobial screening of pyrazolo-3-aryl quinazolin-4(3h)ones  

Digital Repository Infrastructure Vision for European Research (DRIVER)

2-thio-3-aryl quinazolin-4(3H)one (1) was synthesized by reacting anthranilic acid with thiocarbamate salts of substituted aniline and carbon disulphide, which on reflux with excess of hydrazine hydrate to form 2-hydrazino quinazolin-4(3H)one derivatives (2). The reaction of (2) with variously substituted aryl aldehydes gave the corresponding hydrazones (3). Further, the cyclization of compound (3) in acetic anhydride gave tricyclic pyrazoloquinazolinones (4). All newly synthesized compounds ...

2010-01-01

90

Synthesis and Antimicrobial Screening of Pyrazolo-3-Aryl Quinazolin-4(3H)ones  

Digital Repository Infrastructure Vision for European Research (DRIVER)

2-thio-3-aryl quinazolin-4(3H)one (1) was synthesized by reacting anthranilic acid with thiocarbamate salts of substituted aniline and carbon disulphide, which on reflux with excess of hydrazine hydrate to form 2-hydrazino quinazolin-4(3H)one derivatives (2). The reaction of (2) with variously substituted aryl aldehydes gave the corresponding hydrazones (3). Further, the cyclization of compound (3) in acetic anhydride gave tricyclic pyrazoloquinazolinones (4). All newly synthesized compounds ...

2010-01-01

91

Metallic Halide Thiourea Compounds.  

Science.gov (United States)

Divalant metal halide-thiorea compounds are effective as extreme pressure additives in various lubricating compositions which include synthetic and mineral oil base lubricants. An intermediate N,N' or N,N,N'N', substituted thiourea is first synthesized an...

J. Ryer P. M. Kerschner W. C. Bradbury

1965-01-01

92

Synthesis and fungicidal activity of aryl carbamic acid-5-aryl-2-furanmethyl ester.  

Science.gov (United States)

Chitin, a major structural component of insect cuticle and fungus cell wall but absent in plants and vertebrates, is regarded as a safe and selective target for pest control agents. Chitin synthesis inhibitors (CSIs) have been well-known as insect growth regulators (IGRs) but rarely found as fungicides in agriculture. To find novel CSIs with good activity, benzoylphenylurea, a typical kind of CSIs, was chosen as the lead compound and 26 novel aryl carbamic acid-5-aryl-2-furanmethyl esters were designed by converting the urea linkages of benzoylphenylureas to carbamic acid esters and changing the aniline parts into furanmethyl groups. The title compounds were synthesized and their structures confirmed by IR, (1)H NMR, and elemental analysis. Preliminary insecticidal and fungicidal bioassays were carried out. The results indicated that the title compounds had no insecticidal effect on Culex pipiens pallens and Plutella xylostella Linnaeus , but most compounds exhibited good fungicidal activities against Corynespora cassiicola , Thanatephorus cucumeris , Botrytis cinerea , and Fusarium oxysporum . In particular, compounds V-4, V-6, V-7, and V-8 showed better activities against the four strains than those of the commercialized fungicides. The morphologic result suggested that compound V-21 had disturbed the cell wall formation of C. cassiicola. The results indicated that modification on the urea linkage of benzoylphenylurea was an effective way to discover new candidates for fungicides. PMID:20151651

Li, Ying; Li, Bao-Ju; Ling, Yun; Miao, Hong-Jian; Shi, Yan-Xia; Yang, Xin-Ling

2010-03-10

93

Fe(OTf)3-catalyzed ?-benzylation of aryl methyl ketones with electrophilic secondary and aryl alcohols.  

Science.gov (United States)

Acid-catalyzed Friedel-Crafts alkylation of 1,3-dicarbonyl compounds with electrophilic alcohols, is known to be an effective C-C bond forming reaction. However, until now, this reaction has not been amenable for ?-alkylation of aryl methyl ketones because of the notoriously low nucleophilicities of these compounds. Therefore, ?-alkylation of aryl methyl ketone relies on precious metal catalysts and also, the use of primary alcohols is mandatory. In this study, we found that a system composed of a Fe(OTf)3 catalyst and chlorobenzene solvent is sufficient to promote the title Friedel-Crafts reaction by using benzhydrols as electrophiles. 3,4-Dihydro-9-(2-hydroxy-4,4-dimethyl-6-oxo-1-cyclohexen-1-yl)-3,3-dimethyl-xanthen-1(2H)-one was also applicable as an electrophile in this type of benzylation reaction. On the basis of this result, a three-component reaction of salicylaldehyde, dimedone, and aryl methyl ketone was also developed, and this provided an efficient way for the synthesis of densely substituted 4H-chromene derivatives. PMID:24124171

Pan, Xiaojuan; Li, Minghao; Gu, Yanlong

2014-01-01

94

Aryl diazonium salts new coupling agents and surface science  

CERN Document Server

Diazonium compounds are employed as a new class of coupling agents to link polymers, biomacromolecules, and other species (e. g. metallic nanoparticles) to the surface of materials. The resulting high performance materials show improved chemical and physical properties and find widespread applications. The advantage of aryl diazonium salts compared to other surface modifiers lies in their ease of preparation, rapid (electro)reduction, large choice of reactive functional groups, and strong aryl-surface covalent bonding.This unique book summarizes the current knowledge of the surface and

Chehimi, Mohamed Mehdi

2012-01-01

95

Chiral aryl-copper(III) electrophiles: new opportunities in catalytic enantioselective arylations and domino processes.  

Science.gov (United States)

"Chiral aryl cation" equivalents: The combination of diaryliodonium salts and catalytic amounts of chiral copper complexes provides facile access to "chiral aryl cation" synthons. These reagents offer new possibilities for asymmetric arylation reactions that initiate further domino processes. PMID:23001994

Rousseaux, Sophie; Vrancken, Emmanuel; Campagne, Jean-Marc

2012-10-29

96

Nucleophilic Addition of Nitrogen to Aryl Cations: Mimicking Titan Chemistry  

Science.gov (United States)

The reactivity of aryl cations toward molecular nitrogen is studied systematically in an ion trap mass spectrometer at 102 Pascal of nitrogen, the pressure of the Titan main haze layer. Nucleophilic addition of dinitrogen occurs and the nature of aryl group has a significant influence on the reactivity, through inductive effects and by changing the ground state spin multiplicity. The products of nitrogen activation, aryldiazonium ions, react with typical nitriles, aromatic amines, and alkynes (compounds that are relevant as possible Titan atmosphere constituents) to form covalently bonded heterocyclic products. Theoretical calculations at the level [DFT(B3LYP)/6-311++G(d,p)] indicate that the N2 addition reaction is exothermic for the singlet aryl cations but endothermic for their triplet spin isomers. The -OH and -NH2 substituted aryl ions are calculated to have triplet ground states, which is consistent with their decreased nitrogen addition reactivity. The energy needed for the generation of the aryl cations from their protonated precursors (ca. 340 kJ/mol starting with protonated aniline) is far less than that required to directly activate the nitrogen triple bond (the lowest energy excited state of N2 lies ca. 600 kJ/mol above the ground state). The formation of aza-aromatics via arene ionization and subsequent reactions provide a conceivable route to the genesis of nitrogen-containing organic molecules in the interstellar medium and Titan haze layers.

Li, Anyin; Jjunju, Fred P. M.; Cooks, R. Graham

2013-11-01

97

Pd-catalyzed ?-arylation of ?,?-difluoroketones with aryl bromides and chlorides. A route to difluoromethylarenes.  

Science.gov (United States)

We report the Pd-catalyzed ?-arylation of ?,?-difluoroketones with aryl and heteroaryl bromides and chlorides catalyzed by an air- and moisture-stable palladacyclic complex containing P(t-Bu)Cy2 as ligand. The combination of this Pd-catalyzed arylation and base-induced cleavage of the acyl-aryl C-C bond within the ?-aryl-?,?-difluoroketone constitutes a one-pot, two-step procedure to synthesize difluoromethylarenes from aryl halides. A broad range of electronically varied aryl and heteroaryl bromides and chlorides underwent these two transformations, providing ?-aryl-?,?-difluoroketones, difluoromethylarenes, and difluoromethylheteroarenes in high yields. PMID:24588379

Ge, Shaozhong; Cha?adaj, Wojciech; Hartwig, John F

2014-03-19

98

A New Routine for the Synthesis of N-substituted-N-(sulfonyl bromoacetamides with ZnCl2 as a Catalyst  

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Full Text Available A series of N-acylated N-substituted sulfonamides was prepared for the first time in good yields and with excellent conversion by the reaction of N-substituted-N-(p-toluene sulfonamides (1 with acetyl chloride and bromoacetyl bromide (2, respectively, in the presence of a catalytic amount of anhydrous ZnCl2.

Milan Potácek

1999-08-01

99

A New Routine for the Synthesis of N-substituted-N-(sulfonyl) bromoacetamides with ZnCl2 as a Catalyst  

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A series of N-acylated N-substituted sulfonamides was prepared for the first time in good yields and with excellent conversion by the reaction of N-substituted-N-(p-toluene) sulfonamides (1) with acetyl chloride and bromoacetyl bromide (2), respectively, in the presence of a catalytic amount of anhydrous ZnCl2.

Martin Trávnícek; Milan Potácek

1999-01-01

100

Organic Transformations on ?-Aryl Organometallic  

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This work reviews recent developments in the field of organic transformations on ?-aryl organometallic complexes. The general notion that M-C bonds are kinetically labile, highly reactive, and incompatible with typical reaction conditions met in organic synthesis has limited the use of these synthetic strategies thus far. However, organic transformations on metal-bound ?-aryl fragments are being used more and more by chemists in both industry and academia. In this Review, emphasis is put o...

Gagliardo, M.; Snelders, D. J. M.; Chase, P. A.; Klein Gebbink, R. J. M.; Klink, G. P. M.; Koten, G.

2007-01-01

 
 
 
 
101

Assessment of synthetic methods for the preparation of N-beta-D-glucopyranosyl-N'-substituted ureas, -thioureas and related compounds  

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Preparation of O-peracetylated N-beta-D-glucopyranosyl-N'-acyl urea derivatives resulted in the formation of anomeric mixtures under the following conditions: acylation of O-peracetylated beta-D-glucopyranosyl urea by acyl chlorides in the presence of ZnCl2 in refluxing CHCl3; addition of O-peracetylated beta-D-glucopyranosylamine to acyl isocyanates in acetonitrile at rt; addition of carboxamides to in situ prepared O-peracetylated beta-D-glucopyranosyl isocyanate in refluxing toluene. Depro...

Hse Csaba; Somsk Lszl (1954-) (vegysz); Felfldi Nra (1979-) (vegysz); Knya Blint (1984-) (vegysz); Telep Katalin (1982-) (vegysz); Bokor va (1982-) (vegysz); Czifrk Katalin (1978-) (vegysz)

2008-01-01

102

Roles of the Enantioselective Glutathione S-Transferases in Cleavage of ?-Aryl Ether  

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Cleavage of the ?-aryl ether linkage is the most important process in lignin degradation. Here we characterize the three tandemly located glutathione S-transferase (GST) genes, ligF, ligE, and ligG, from low-molecular-weight lignin-degrading Sphingomonas paucimobilis SYK-6, and we describe the actual roles of these genes in the ?-aryl ether cleavage. Based on the identification of the reaction product by electrospray ionization-mass spectrometry, a model compound of ?-aryl ether, ?-(2-met...

Masai, Eiji; Ichimura, Atsushi; Sato, Yusuke; Miyauchi, Keisuke; Katayama, Yoshihiro; Fukuda, Masao

2003-01-01

103

Synthesis, Antibacterial and Antifungal Activity of 4-Substituted-5-Aryl-1,2,4-Triazoles  

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Full Text Available A few 4-allyl/amino-5-aryl-1,2,4-triazoles were synthesized and tested for antibacterial and antifungal effects against Escherichia coli, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Aspergillus niger and Candida albicans. 4-Allyl-5-aryl-1,2,4-triazoles were obtained by the oxidative cyclization of the appropriate 1-substituted-4-allylthiosemicarbazides and 4-amino-5-aryl-1,2,4-triazoles were obtained by cyclization of the potassium salts of appropriately substituted dithiocarbazinic acids with hydrazine hydrate. The new synthesized compounds were characterized using IR, 1H- NMR, 13C-NMR and UV spectral data together with elemental analysis.

Aleksandra Buzarovska

2001-09-01

104

Solvent-Free Synthesis, DNA-Topoisomerase II Activity and Molecular Docking Study of New Asymmetrically N,N'-Substituted Ureas  

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Full Text Available A new series of asymmetrically N,N'-substituted ureas 2025 was prepared using solvent free conditions, which is an eco-friendly methodology, starting with Schiff bases derived from cinnamaldehyde and p-substituted anilines, which are subsequently submitted to reduction reactions that afford the corresponding asymmetric secondary amines. All of the intermediates were prepared using solvent free reactions, which were compared to traditional methodologies. All of the reactions required a remarkably short amount of time and provided good yields when solvent free conditions were employed compared to other methodologies. The DNA-topoisomerase II-? (topo II-? activity was evaluated in relaxation assays, which showed that all of the compounds inhibited the enzyme activity at 10 ?M, except for urea 24. Furthermore, a molecular docking study indicated that the compounds 2025 binding to the topo II-? are able to interact with the same binding site as the anticancer drug etoposide, suggesting that the ureas could inhibit the enzyme by the same mechanism of action observed for etoposide, which prevents re-ligation of the DNA strands.

Aurea Echevarria

2012-11-01

105

Palladium-Catalyzed Indole, Pyrrole, and Furan Arylation by Aryl Chlorides  

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The palladium-catalyzed direct arylation of indoles, pyrroles, and furans by aryl chlorides has been demonstrated. The method employs a palladium acetate catalyst, 2-(dicyclohexylphosphino)-biphenyl ligand, and an inorganic base. Electron-rich and electron-poor aryl chlorides as well as chloropyridine coupling partners can be used and arylated heterocycles are obtained in moderate ...

Nadres, Enrico T.; Lazareva, Anna; Daugulis, Olafs

2011-01-01

106

Identification and expression of aryl hydrocarbon receptors (AhR1 and AhR2) provide insight in an evolutionary context regarding sensitivity of white sturgeon (Acipenser transmontanus) to dioxin-like compounds.  

Science.gov (United States)

Sturgeons are ancient fishes, which are endangered in many parts of the world. Due to their benthic nature and longevity, sturgeon are at great risk of exposure to bioaccumulative contaminants such as dioxin-like compounds (DLCs). Despite their endangered status, little research has been conducted to characterize the relative sensitivity of sturgeons to DLCs. Proper assessment of risk of DLCs posed to these fishes therefore, requires a better understanding of this sensitivity and the factors that are driving it. Adverse effects associated with exposure to DLCs are mediated by the aryl hydrocarbon receptor (AhR). This study identified and characterized two distinct AhRs, AhR1 and AhR2, in white sturgeon (Acipenser transmontanus) for the first time as a first step in studying the relative sensitivities of sturgeons to DLCs. Furthermore, tissue-specific expression of both AhRs under basal conditions and in response to exposure to the model DLC, ?-naphthoflavone (?NF), was determined. The sequence of amino acids of AhR1 of white sturgeon had greater similarity to AhRs of tetrapods, including amphibians, birds, and mammals, than to AhR1s of other fishes. The sequence of amino acids in the ligand binding domain of the AhR1 had greater than 80% similarity to AhRs known to bind DLCs and was less similar to AhRs not known to bind DLCs. AhR2 of white sturgeon had greatest similarity to AhR2 of other fishes. Profiles of expression of AhR1 and AhR2 in white sturgeon were distinct from those known in other fishes and appear more similar to profiles observed in birds. Expressions of both AhR1 and AhR2 of white sturgeon were greatest in liver and heart, which are target organs for DLCs. Furthermore, abundances of transcripts of AhR1 and AhR2 in all tissues from white sturgeon were greater than controls (up to 35-fold) following exposure to ?NF. Based upon both AhRs having similar abundances of transcript in target organs of DLC toxicity, both AhRs being up-regulated following exposure to ?NF, and both AhRs having greatest similarity to AhRs known to bind DLCs, it is hypothesized that both AhR1 and AhR2 of white sturgeon might mediate effects of DLCs in this species. Since current risk assessments are based on data derived largely from highly divergent fishes within the Salmonidae, presence of two functional AhRs in white sturgeon, one of which has greatest similarity to AhRs of birds, might have significant implications for the sensitivity of sturgeons to DLCs compared to other fishes. PMID:24632312

Doering, Jon A; Wiseman, Steve; Beitel, Shawn C; Giesy, John P; Hecker, Markus

2014-05-01

107

BorArAm - Catalytic Asymmetric Arylating Cyclizations: A New Route to Chiral Bicyclic Amines  

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Nowadays neurodegenerative diseases such as Alzheimers disease and Parkinson disease represent a worldwide health threat. Rasagiline is one well-known medication for the treatment of Parkinson's disease, but more and cheaper alternatives are required.1 For this reason, our group is currently investigating a new catalytic asymmetric arylating2 cyclization route - borylation-arylation-amination (BorArAm) (Scheme 1) giving useful potential lead compounds based on the rasagiline core structure...

Mendes, Paulo J.; Viana, H.; Marques, C. S.; Burke, Anthony J.

2013-01-01

108

Toxicity Studies on Novel N-Substituted Bicyclo-Heptan-2-Amines at NMDA Receptors  

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Full Text Available Several novel norcamphor derivatives were designed and synthesized as uncompetitive NMDA receptor antagonists at the phencyclidine (PCP binding site. Such compounds have potential as ligands for understanding and possibly the treatment of several neurodegenerative disorders and other glutamate-dependent disorders. We examined the toxic effects of the compounds as compared with memantine, an NMDA receptor antagonist that is FDA approved for treatment of Alzheimers disease, by testing these compounds on two cell lines: MDCK (to mimic blood brain barrier and N2a (a neuronal cell line. The compounds showed toxicity profiles similar to those of memantine i.e., dose dependence above 100 ?M and IC50 values above 150 ?M for each cell line. It is known that the serum level of memantine under therapeutic conditions in patients is about 1 M, indicting these compounds could have acceptable therapeutic indexes. 2-Phenyl-N-(2-(piperidin-1-yl ethylbicyclo[2.2.1]heptan-2-amine (5a was found to possess acceptable toxicity profiles in both cell lines. Interestingly, this was the compound identified as a good lead in our previous studies based on binding and anticonvulsant (MES activity studies. It has thus emerged as an excellent lead compound for further studies.

Michelle Farbaniec

2013-04-01

109

Palladium-catalyzed aminosulfonylation of aryl halides.  

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The palladium-catalyzed three-component coupling of aryl iodides, sulfur dioxide, and hydrazines to deliver aryl N-aminosulfonamides is described. The colorless crystalline solid DABCO(SO(2))(2) was used as a convenient source of sulfur dioxide. The reaction tolerates significant variation of both the aryl iodide and hydrazine coupling partners.

Nguyen, B.; Emmett, Ej; Willis, Mc

2010-01-01

110

Intramolecular arylation of amino acid enolates.  

Science.gov (United States)

Dianionic enolates formed from N'-aryl urea derivatives of amino acids undergo intramolecular C-arylation by attack of the enolate anion on the N'-aryl ring, leading to a hydantoin derivative of a quaternary amino acid. In situ IR studies allow identification of four intermediates on the reaction pathway. PMID:24022183

Atkinson, Rachel C; Leonard, Daniel J; Maury, Julien; Castagnolo, Daniele; Volz, Nicole; Clayden, Jonathan

2013-10-28

111

NiXantphos: A Deprotonatable Ligand for Room-Temperature Palladium-Catalyzed Cross-Couplings of Aryl Chlorides.  

Science.gov (United States)

Although the past 15 years have witnessed the development of sterically bulky and electron-rich alkylphosphine ligands for palladium-catalyzed cross-couplings with aryl chlorides, examples of palladium catalysts based on either triarylphosphine or bidentate phosphine ligands for efficient room temperature cross-coupling reactions with unactivated aryl chlorides are rare. Herein we report a palladium catalyst based on NiXantphos, a deprotonatable chelating aryldiphosphine ligand, to oxidatively add unactivated aryl chlorides at room temperature. Surprisingly, comparison of an extensive array of ligands revealed that under the basic reaction conditions the resultant heterobimetallic Pd-NiXantphos catalyst system outperformed all the other mono- and bidentate ligands in a deprotonative cross-coupling process (DCCP) with aryl chlorides. The DCCP with aryl chlorides affords a variety of triarylmethane products, a class of compounds with various applications and interesting biological activity. Additionally, the DCCP exhibits remarkable chemoselectivity in the presence of aryl chloride substrates bearing heteroaryl groups and sensitive functional groups that are known to undergo 1,2-addition, aldol reaction, and O-, N-, enolate-?-, and C(sp(2))-H arylations. The advantages and importance of the Pd-NiXantphos catalyst system outlined herein make it a valuable contribution for applications in Pd-catalyzed arylation reactions with aryl chlorides. PMID:24745758

Zhang, Jiadi; Bellomo, Ana; Trongsiriwat, Nisalak; Jia, Tiezheng; Carroll, Patrick J; Dreher, Spencer D; Tudge, Matthew T; Yin, Haolin; Robinson, Jerome R; Schelter, Eric J; Walsh, Patrick J

2014-04-30

112

Antimicrobial and genotoxic activities of N-substituted 2,2'-dicarboxamidodiphenyldisulfides.  

Science.gov (United States)

This paper describes the in vitro evaluation of antibacterial, antifungal and genotoxic activities of a series of 2,2'-dicarboxamidodiphenyldisulfides. All the studied compounds exhibited antibacterial activity against Bacillus subtilis. Most compounds were also active against Staphylococcus aureus. Several compounds were active against Saccharomyces cerevisiae and, in most cases, also against Candida tropicalis. No effects were observed against Escherichia coli or Aspergillus niger. Antimicrobial activity turned out to be affected by the substituent in the benzene ring and structure-activity relationships were found. The antibacterial and antifungal activities of the studied derivatives were compared with those of the corresponding 1,2-benzisothiazolin-3-ones and in some cases strong differences were observed. None of the tested compounds contained alerting groups or showed genotoxic properties. PMID:1510794

Zani, F

1992-02-01

113

New antithrombotic aryl-sulfonylthiosemicarbazide derivatives synthesized from natural safrole  

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Full Text Available As part of a research program aiming at the synthesis and pharmacological evaluation of novel lead-compounds exploring Brazilian abundant natural products, we describe herein the synthesis and the antithrombotic profile of new aryl-sulfonylsemicarbazides and aryl-sulfonylthiosemicarbazides (10a-d. The new derivatives, designed with basis on the molecular hybridization concept, were prepared in good yields from natural safrole (9, isolated from sassafras oil. The anti-aggregating activity of these new derivatives (10a-d on platelet aggregation induced by ADP, collagen, arachidonic acid and U-46619, indicates an important antithrombotic profile for the 6-methyl-3,4-methylenedioxyphenyl-sulfonyl-N-phenylthiosemicarbazide derivative (10d, acting at the arachidonic acid cascade and representing a new lead-compound with antithrombotic activity.

Lima Ldia M.

1999-01-01

114

A facile synthesis of N-H- and N-substituted acridine-1,8-diones under sonic condition.  

Science.gov (United States)

Synthesis of an assembly of structurally important N-H- and N-substituted acridine-1,8-diones by CAN (ceric ammonium nitrate) catalysed one-pot four-component reaction of electron-deficient and electron-rich aromatic aldehydes and aromatic amines or ammonium acetate and dimedone or cyclohexyl-1,3-diones at 26C under sonic condition is reported. The method is clean and energy efficient as it uses a greener method and an eco-friendly catalyst. PMID:24501587

Sudha, S; Pasha, M A

2013-01-01

115

Optimized Anti-pathogenic Agents Based on Core/Shell Nanostructures and 2-((4-Ethylphenoxyethyl-N-(substituted-phenylcarbamothioyl-benzamides  

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Full Text Available The purpose of this study was to design a new nanosystem for catheter surface functionalization with an improved resistance to Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 colonization and subsequent biofilm development. New 2-((4 ethylphenoxymethyl-N-(substituted-phenylcarbamothioyl-benzamides were synthesized and used for coating a core/shell nanostructure. Their chemical structures were elucidated by NMR, IR and elemental analysis, being in agreement with the proposed ones. Fe3O4/C12 of up to 5 nm size had been synthesized with lauric acid as a coating agent and characterized by XRD, FT-IR, TGA, TEM and biological assays. The catheter pieces were coated with the fabricated nanofluid in magnetic field. The microbial adherence ability was investigated in 6 multiwell plates by using culture based methods and Scanning Electron Microscopy (SEM. The nanoparticles coated with the obtained compounds 1ac inhibited the adherence and biofilm development ability of the S. aureus and P. aeruginosa tested strains on the catheter functionalized surface, as shown by the reduction of viable cell counts and SEM examination of the biofilm architecture. Using the novel core/shell/adsorption-shell to inhibit the microbial adherence could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with improved anti-biofilm properties.

Mariana Carmen Chifiriuc

2012-10-01

116

Optimized Anti-pathogenic Agents Based on Core/Shell Nanostructures and 2-((4-Ethylphenoxy)ethyl)-N-(substituted-phenylcarbamothioyl)-benzamides.  

Science.gov (United States)

The purpose of this study was to design a new nanosystem for catheter surface functionalization with an improved resistance to Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 colonization and subsequent biofilm development. New 2-((4 ethylphenoxy)methyl)-N-(substituted-phenylcarbamothioyl)-benzamides were synthesized and used for coating a core/shell nanostructure. Their chemical structures were elucidated by NMR, IR and elemental analysis, being in agreement with the proposed ones. Fe(3)O(4)/C(12 )of up to 5 nm size had been synthesized with lauric acid as a coating agent and characterized by XRD, FT-IR, TGA, TEM and biological assays. The catheter pieces were coated with the fabricated nanofluid in magnetic field. The microbial adherence ability was investigated in 6 multiwell plates by using culture based methods and Scanning Electron Microscopy (SEM). The nanoparticles coated with the obtained compounds 1a-c inhibited the adherence and biofilm development ability of the S. aureus and P. aeruginosa tested strains on the catheter functionalized surface, as shown by the reduction of viable cell counts and SEM examination of the biofilm architecture. Using the novel core/shell/adsorption-shell to inhibit the microbial adherence could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with improved anti-biofilm properties. PMID:23202915

Limban, Carmen; Grumezescu, Alexandru Mihai; Saviuc, Crina; Voicu, Georgeta; Predan, Gentiana; Sakizlian, Robert; Chifiriuc, Mariana Carmen

2012-01-01

117

Substituent effect on IR, 1H and 13C NMR spectral data in n-(substituted phenyl-2-cyanoacetamides: A correlation study  

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Full Text Available Linear free energy relationships (LFER were applied to the IR, 1H and 13C NMR spectral data of N-(substituted phenyl-2-cyanoacetamides. A variety of substituents were employed for phenyl substitution and fairly good correlations were obtained using the simple Hammett and the Hammett-Taft dual substituent parameter equations. The correlation results of the substituent induced 13C NMR chemical shifts (SCS of the C1, C=O and N-H atom indicated different sensitivity with respect to electronic substituent effects. A better correlation of the SCSC=O with a combination of electrophilic and nucleophilic substituent constants indicated a significant contribution of extended resonance interaction (?-delocalization within the ?1-unit. The conformations of the investigated compounds were studied using the DFT B3LYP/6-311G method and, together with the results of 13C NMR and IR spectroscopic studies, a better insight into the influence of such a structure on the transmission of electronic substituent effects was obtained.

Marinkovi? Aleksandar D.

2013-01-01

118

Palladium-catalyzed ?-arylation of 2-chloroacetates and 2-chloroacetamides.  

Science.gov (United States)

A method has been developed for the Pd-catalyzed synthesis of ?-(hetero)aryl esters and amides through a Suzuki-Miyaura cross-coupling reaction. This method avoids the use of strong base, does not necessitate inert or low temperature formation of reagents, and does not require the use of a large excess of organometallic reagent. Utilization of organotrifluoroborate salts as nucleophilic partners allows a variety of functional groups and heterocyclic compounds to be tolerated. PMID:23570264

Molander, Gary A; Traister, Kaitlin M; Barcellos, Thiago

2013-04-19

119

Palladium-Catalyzed ?-Arylation of 2-Chloroacetates and 2-Chloroacetamides  

Science.gov (United States)

A method has been developed for the Pd-catalyzed synthesis of ?-(hetero)aryl esters and amides through a SuzukiMiyaura cross-coupling reaction. This method avoids the use of strong base, does not necessitate inert or low temperature formation of reagents, and does not require the use of a large excess of organometallic reagent. Utilization of organotrifluoroborate salts as nucleophilic partners allows a variety of functional groups and heterocyclic compounds to be tolerated.

Traister, Kaitlin M.; Barcellos, Thiago

2013-01-01

120

1-Aryl-2-dimethylaminomethyl-2-propen-1-one hydrochlorides and related adducts: A quest for selective cytotoxicity for malignant cells  

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The primary objective of this study was to discover one or more clusters of compounds which are not equitoxic but display cytoselectivity toward different malignant cells. Furthermore a most important consideration is that such molecules should also display greater cytotoxic potencies to tumors than normal tissues. Two series of compounds are described which meet these criteria, namely the 1-aryl-2-dimethylaminomethyl-2-propen-1-one hydrochlorides 1ae and 1-aryl-3-dimethylamino-2-hydroxyme...

2008-01-01

 
 
 
 
121

Novel scheme for biosynthesis of aryl metabolites from L-phenylalanine in the fungus Bjerkandera adusta.  

Science.gov (United States)

Aryl metabolite biosynthesis was studied in the white rot fungus Bjerkandera adusta cultivated in a liquid medium supplemented with L-phenylalanine. Aromatic compounds were analyzed by gas chromatography-mass spectrometry following addition of labelled precursors ((14)C- and (13)C-labelled L-phenylalanine), which did not interfere with fungal metabolism. The major aromatic compounds identified were benzyl alcohol, benzaldehyde (bitter almond aroma), and benzoic acid. Hydroxy- and methoxybenzylic compounds (alcohols, aldehydes, and acids) were also found in fungal cultures. Intracellular enzymatic activities (phenylalanine ammonia lyase, aryl-alcohol oxidase, aryl-alcohol dehydrogenase, aryl-aldehyde dehydrogenase, lignin peroxidase) and extracellular enzymatic activities (aryl-alcohol oxidase, lignin peroxidase), as well as aromatic compounds, were detected in B. adusta cultures. Metabolite formation required de novo protein biosynthesis. Our results show that L-phenylalanine was deaminated to trans-cinnamic acid by a phenylalanine ammonia lyase and trans-cinnamic acid was in turn converted to aromatic acids (phenylpyruvic, phenylacetic, mandelic, and benzoylformic acids); benzaldehyde was a metabolic intermediate. These acids were transformed into benzaldehyde, benzyl alcohol, and benzoic acid. Our findings support the hypothesis that all of these compounds are intermediates in the biosynthetic pathway from L-phenylalanine to aryl metabolites. Additionally, trans-cinnamic acid can also be transformed via beta-oxidation to benzoic acid. This was confirmed by the presence of acetophenone as a beta-oxidation degradation intermediate. To our knowledge, this is the first time that a beta-oxidation sequence leading to benzoic acid synthesis has been found in a white rot fungus. A novel metabolic scheme for biosynthesis of aryl metabolites from L-phenylalanine is proposed. PMID:10742235

Lapadatescu, C; Ginis, C; Le Qur, J L; Bonnarme, P

2000-04-01

122

Synthesis, antimycobacterial and antibacterial activity of ciprofloxacin derivatives containing a N-substituted benzyl moiety.  

Science.gov (United States)

We report herein the design and synthesis of a series of novel ciprofloxacin (CPFX) derivatives with remarkable improvement in lipophilicity by introducing a substituted benzyl moiety to the N atom on the C-7 piperazine ring of CPFX. Antimycobacterial and antibacterial activity of the newly synthesized compounds was evaluated. Results reveal that compound 4f has good in vitro activity against all of the tested Gram-positive strains including MRSA and MRSE (MICs: 0.06-32 ?g/mL) which is two to eightfold more potent than or comparable to the parent drug CPFX (MICs: 0.25-128 ?g/mL), Gram-negative bacteria P. aeruginosa (MICs: 0.5-4 ?g/mL) and M. tuberculosis H37Rv ATCC 27294 (MIC: 1 ?g/mL). PMID:22884110

Wang, Shuo; Jia, Xue-Dong; Liu, Ming-Liang; Lu, Yu; Guo, Hui-Yuan

2012-09-15

123

SYNTHESIS AND BIOLOGICAL EVALUATION OF SOME NOVEL PYRAZOLINE DERIVATIVES DERIVED FROM N-SUBSTITUTED QUINOLINYL CHALCONES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A series of novel substituted 1-amino-3-(5-phenyl-4, 5-dihydro-1H-pyrazol-3-yl) quinolin-2(1H)-one (AJP1-AJP8) have been synthesized upon reaction with 1-amino-3-cinnamoyl-quinolin-2(1H)-one by using hydrazine hydrate as cyclising medium in alcohol medium. 1-amino-3-cinnamoyl-quinolin-2(1H)-one were synthesized by condensing 3-acetyl-1-amino-quinolin-2-one with different substituted benzaldehyde in presence of ethanolic KOH. The structures of the final synthesized compounds were confirmed by ...

2013-01-01

124

Polymeric media comprising polybenzimidazoles N-substituted with organic-inorganic hybrid moiety  

Energy Technology Data Exchange (ETDEWEB)

A PBI compound includes imidazole nitrogens at least a portion of which are substituted with an organic-inorganic hybrid moiety may be included in a separator medium. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2-- where R is selected from among methyl, phenyl, vinyl, and allyl. The separatory medium may exhibit an H.sub.2, Ar, N.sub.2, O.sub.2, CH.sub.3, or CO.sub.2 gas permeability greater than the gas permeability of a comparable separatory medium comprising the PBI compound without substitution. The separatory medium may further include an electronically conductive medium and/or ionically conductive medium. The separatory medium may be used as a membrane (semi-permeable, permeable, and non-permeable), a barrier, an ion exhcange media, a filter, a gas chromatography coating (such as stationary phase coating in affinity chromatography), etc.

Klaehn, John R [Idaho Falls, ID; Peterson, Eric S [Idaho Falls, ID; Wertsching, Alan K [Idaho Falls, ID; Orme, Christopher J [Shelley, ID; Luther, Thomas A [Idaho Falls, ID; Jones, Michael G [Pocatello, ID

2009-12-15

125

Consecutive three-component synthesis of 3-(hetero)aryl-1H-pyrazoles with propynal diethylacetal as a three-carbon building block.  

Science.gov (United States)

A novel consecutive three-component synthesis of 3-(hetero)aryl-1H-pyrazoles via room temperature Sonogashira arylation of propynal diethylacetal used as a propargyl aldehyde synthetic equivalent has been disclosed. The final acetal cleavage-cyclocondensation with hydrazine hydrochloride at 80 C rapidly furnishes the title compounds in a one-pot fashion. PMID:22064273

Levi, Lucilla; Boersch, Christina; Gers, Charlotte F; Merkul, Eugen; Mller, Thomas J J

2011-01-01

126

Application of Daugulis Copper-Catalyzed Direct Arylation to the Synthesis of 5-Aryl Benzotriazepines  

Science.gov (United States)

A method for the direct arylation of benzotriazepines is reported, employing an aryl iodide as the coupling partner, copper iodide as the catalyst, and lithium t-butoxide as the base. A variety of electron-rich, electron-poor, and sterically hindered aryl iodides are compatible with the reaction conditions. The arylation reaction can also be performed outside a glovebox in air without a significant decrease in yield. Furthermore, convenient microwave conditions for carrying out this transformation are reported.

Yotphan, Sirilata; Bergman, Robert G.; Ellman, Jonathan A.

2009-01-01

127

Selective Monoarylation of Acetate Esters and Aryl Methyl Ketones Using Aryl Chlorides  

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Simple, efficient procedures for the monoarylation of acetate esters and aryl methyl ketones using aryl chlorides are presented. Previously, no general method was available to ensure the highly selective monoarylation of these classes of substrates using aryl chlorides. Using palladium precatalysts recently reported by our group, these reactions are easily accomplished under mild conditions that tolerate a wide array of heterocyclic substrates.

Biscoe, Mark R.; Buchwald, Stephen Leffler

2009-01-01

128

Synthesis of ?-Arylphosphonates Using Copper-Catalyzed ?-Arylation and Deacylative ?-Arylation of ?-Ketophosphonates  

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Efficient methods for the direct arylation and deacylative arylation of ?-ketophosphonates with iodoarenes in presence of a copper(I) or a copper(II) salt as the catalysts were developed. The corresponding ?-arylphosphonates were obtained in high yields. A tentative mechanism for the deacylative arylation reaction was proposed on the basis of the experimental data.

Rout, Laxmidhar; Regati, Sridhar; Zhao, Cong-gui

2011-01-01

129

Titanium nitride-nickel nanocomposite as heterogeneous catalyst for the hydrogenolysis of aryl ethers.  

Science.gov (United States)

Lignin from biomass can become a sustainable source of aromatic compounds. Its depolymerization can be accomplished through hydrogenolysis, although the development of catalysts based on cheap and abundant metals is lacking. Herein, a sustainable composite based on titanium nitride and nickel is synthesized and employed as catalyst for the hydrogenolysis of aryl ethers as models for lignin. The catalytic activity of the new material during hydrogenation reactions is proven to be superior to that of either component alone. In particular, different aryl ethers could be efficiently converted under relatively mild conditions into aromatic compounds and cycloalkanes within minutes. PMID:24437507

Molinari, Valerio; Giordano, Cristina; Antonietti, Markus; Esposito, Davide

2014-02-01

130

The aryl hydrocarbon receptor repressor  

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The aryl hydrocarbon receptor repressor (AHRR) is a bHLH/Per-ARNT-Sim transcription factor located in a region of chromosome 5 (5p15.3) that has been proposed to contain one or more tumor suppressor genes. We report here consistent downregulation of AHRR mRNA in human malignant tissue from different anatomical origins, including colon, breast, lung, stomach, cervix, and ovary, and demonstrate DNA hypermethylation as the regulatory mechanism of AHRR gene silencing. Knockdown of AHR...

Zudaire, Enrique; Cuesta, Natalia; Murty, Vundavalli; Woodson, Karen; Adams, Lisa; Gonzalez, Nieves; Marti?nez, Alfredo; Narayan, Gopeshwar; Kirsch, Ilan; Franklin, Wilbur; Hirsch, Fred; Birrer, Michael; Cuttitta, Frank

2008-01-01

131

The decompositions of N-(substituted benzalamino)phthalimide radical cations embody ion-neutral complexes and Stevenson's rule.  

Science.gov (United States)

A previously unreported series of N-(substituted benzalamino)phthalimides was investigated by using the combined techniques of high resolution electron ionization mass spectrometry, metastable decomposition, and collisional activation mass spectrometry. The predominate fragmentation pathway is a McLafferty-type rearrangement. There also occurs, to a lesser extent, a transfer of hydrogen that originates from a substituent remote from the phthalimide moiety and terminates on the phthalimide, The process is interpreted as proceeding via an ion-neutral complex. The effects of substituents on both of the aforementioned fragmentation pathways provide a striking example that gives quantitative evidence for Stevenson's rule. The substituent effects are responsible for a trend in ion abundance that shows a sharp reversal at approximately the ionization energy of the iminium isomer of the phthalimide molecular ion. PMID:24222031

Jacoby, C B; Gross, M L; Zey, R L

1994-09-01

132

Compound  

Science.gov (United States)

We have prepared Ce-doped polycrystalline AgSbTe2.01 compounds from high-purity elements by a melt-quench technique followed by spark plasma sintering, and their thermoelectric transport properties have been investigated in the temperature range of 300 K to 625 K. The actual concentration of Ce was much less than the initial composition, but roughly proportional to it. Small additions of Ce shifted the composition of the homogeneity range from the nearly ideal atomic ratio Ag:Sb:Te = 0.98:1.02:2.01 toward Sb rich (Ag poor), and led to the reemergence of Ag2Te impurity in AgSbTe2 compound. The Ce-doped samples possessed lower electrical conductivity compared with the undoped AgSbTe2.01 compound at room temperature, but the carrier mobility and effective mass were essentially constant, indicating intact band structure near the covalent band maximum upon Ce substitution for Sb. Due to the decrease of lattice vibration anharmonicity resulting from Ce substitution for Sb, the lattice conductivity of the Ce-doped samples was about 0.1 W m-1 K-1 higher than that of the AgSbTe2.01 sample, and the magnitude spanned the range from 0.30 W m-1 K-1 to 0.55 W m-1 K-1. A ZT of 1.20 was achieved at about 615 K for the AgSb0.99Ce0.01Te2.01 sample.

Du, B.; Li, H.; Tang, X.

2014-06-01

133

N-SUBSTITUTION AND 1-ADRENERGIC RECEPTOR AFFINITY OF LAUDANOSINE ANALOGUES  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Benzyltetrahydroisoquinoline (BTHIQ) molecules are able to adopt widely differing conformations that depend on the presence or absence of N-substituents. To assess the possible role of BTHIQ conformation on the affinity of these compounds for a 1-adrenergic receptors, of interest for the management [...] of hypertension, the racemic N-unsubstituted BTHIQ norlaudanosine and a series of N-alkylated derivatives were assessed for binding to rat brain cortical sites labelled with the radioligand [H]prazosin. The a 1-adrenergic affinity in this series increased with the bulk of the substituent on the nitrogen atom, from the N-ethyl to the N-propyl analogue. Comparison of these results with published data for related BTHIQs and for the rigid mimics of the fully extended and semi-folded conformations of laudanosine, tetrahydropalmatine and glaucine, suggested that the a 1-adrenergic receptor binding site is able to accommodate either conformation. The presence of a bulky substituent on the nitrogen atom seems to favor receptor binding independently of the favored conformation, and that the orientation in which BTHIQs are bound probably differs depending on the presence or absence of a hydroxyl group at a key position

ITURRIAGA-VSQUEZ, PATRICIO; CASSELS, BRUCE K; IVORRA, M. DOLORES; D' OCON, M. PILAR.

134

N-SUBSTITUTION AND 1-ADRENERGIC RECEPTOR AFFINITY OF LAUDANOSINE ANALOGUES  

Directory of Open Access Journals (Sweden)

Full Text Available Benzyltetrahydroisoquinoline (BTHIQ molecules are able to adopt widely differing conformations that depend on the presence or absence of N-substituents. To assess the possible role of BTHIQ conformation on the affinity of these compounds for a 1-adrenergic receptors, of interest for the management of hypertension, the racemic N-unsubstituted BTHIQ norlaudanosine and a series of N-alkylated derivatives were assessed for binding to rat brain cortical sites labelled with the radioligand [H]prazosin. The a 1-adrenergic affinity in this series increased with the bulk of the substituent on the nitrogen atom, from the N-ethyl to the N-propyl analogue. Comparison of these results with published data for related BTHIQs and for the rigid mimics of the fully extended and semi-folded conformations of laudanosine, tetrahydropalmatine and glaucine, suggested that the a 1-adrenergic receptor binding site is able to accommodate either conformation. The presence of a bulky substituent on the nitrogen atom seems to favor receptor binding independently of the favored conformation, and that the orientation in which BTHIQs are bound probably differs depending on the presence or absence of a hydroxyl group at a key position

PATRICIO ITURRIAGA-VSQUEZ

2006-09-01

135

Synthesis of N-Substituted 5-Iodouracils as Antimicrobial and Anticancer Agents  

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Full Text Available This study reports the synthesis of some substituted 5-iodouracils and their bioactivities. Alkylation of 5-iodouracils gave predominately N1-substituted-(R-5-iodouracil compounds 7a-d (R = n-C4H9, s-C4H9, CH2C6H11, CH2C6H5 together with N1,N3-disubstituted (R analogs 8a-b (R = n-C4H9, CH2C6H11. Their antimicrobial activity was tested against 27 strains of microorganisms using the agar dilution method. The analogs 7a, 7c and 7d displayed 25-50% inhibition against Branhamella catarrhalis, Neisseria mucosa and Streptococcus pyogenes at 0.128 mg/mL. No antimalarial activity was detected for any of the analogs when tested against Plasmodium falciparum (T9.94. Their anticancer activity was also examined. Cyclohexylmethyl analogs 7c and 8b inhibited the growth of HepG2 cells. Significantly, N1,N3-dicyclohexylmethyl analog 8b displayed the most potent anticancer activity, with an IC50 of 16.5 mg/mL. These 5-iodouracil analogs represent a new group of anticancer and antibacterial agents with potential for development for medicinal applications.

Virapong Prachayasittikul

2009-07-01

136

Formation Routes For Pure and N-substituted Cyclic Hydrocarbon Molecules in The Ionosphere of Titan  

Science.gov (United States)

Titan's upper atmosphere contains large carbonaceous molecules as has been observed by the instruments on board the CASSINI spacecraft. How these large polyatomic molecules are synthesized in such exotic conditions is, thus far, unknown. Molecular ions are in relative abundance in the ionosphere of Titan. Hence, barrierless ion-molecule interactions may play a major role in guiding molecules towards each other and initiating reactions. We study these cold condensation pathways to determine whether they are a viable means of forming large pure hydrocarbon molecules, and nitrogen-containing carbonaceous chains, stacks, and even cyclic compounds. By employing accurate quantum chemical methods we have investigated the processes of growth, structures, nature of bonding, mechanisms, and spectroscopic properties of the ensuing ionic products after pairing small carbon, hydrogen, and nitrogen-containing molecules with major ions observed in the upper atmosphere of Titan, e.g. C2H5+ and HCNH+. We have also studied the ion-neutral association pathways involving pure-carbon molecules e.g. acetylene, ethylene and other hydrocarbons, and their dissociation fragments in a plasma discharge. Additionally, we have investigated how nitrogen atoms are incorporated into the carbon ring during growth. We have used accurate ab initio coupled cluster theory, Mller-Plesset perturbation theory and density functional theory quantum chemical methods together with large correlation consistent basis sets in these investigations. We also employed time-dependent density functional theory and equations-of-motion coupled cluster theory to compute electronic excitation energies and oscillator strengths of the products of the ion-molecule reactions. We obtained accurate vibrational frequencies under the harmonic approximation and vibrational intensities using the double harmonic approximation for fundamental molecular vibrations. We identified three types of bonding motifs with strong, moderate, and weak binding energies among the carbonaceous complexes. Both linear and cyclic isomers identified on the potential energy surface of these molecular complexes are expected to form rather easily due to electrostatic interactions. We uncovered that a series of hydrocarbons with a specific stoichiometric composition prefers cyclic molecule formation rather than chains. Some of the association products we investigated have large oscillator strengths for charge-transfer type electronic excitations in the near infrared and visible regions of the electromagnetic spectrum. Our quantum chemistry computations complement well the results from the molecular/ion plasma experiments performed by the Laboratory Astrochemistry groups at Ames. P. P. Bera, Martin Head-Gordon, and Timothy J. Lee Astron & Astrophys. 535, A74, (2011) P. P. Bera, M. Head-Gordon, and T. J. Lee, 15, 2012-2023,Phys. Chem. Chem. Phys. (2013) P. P. Bera, Roberto Peverati, M. Head-Gordon, and Timothy J. Lee, To be submitted (2013)

Bera, P. P.; Peverati, R.; Head-Gordon, M.; Lee, T. J.

2013-12-01

137

A New Biocatalyst for Production of Optically Pure Aryl Epoxides by Styrene Monooxygenase from Pseudomonas fluorescens ST  

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We developed a biocatalyst by cloning the styrene monooxygenase genes (styA and styB) from Pseudomonas fluorescens ST responsible for the oxidation of styrene to its corresponding epoxide. Recombinant Escherichia coli was able to oxidize different aryl vinyl and aryl ethenyl compounds to their corresponding optically pure epoxides. The results of bioconversions indicate the broad substrate preference of styrene monooxygenase and its potential for the production of several fine chemicals.

1999-01-01

138

A direct method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background In vertebrates, two types of cholinesterases exist, acetylcholinesterase and butyrylcholinesterase. The function of acetylcholinesterase is to hydrolyse acetylcholine, thereby terminating the neurotransmission at cholinergic synapse, while the precise physiological function of butyrylcholinesterase has not been identified. The presence of cholinesterases in tissues that are not cholinergically innervated indicate that cholinesterases may have functions unrelated to neurotransmission. Furthermore, cholinesterases display a genuine aryl acylamidase activity apart from their predominant acylcholine hydrolase activity. The physiological significance of this aryl acylamidase activity is also not known. The study on the aryl acylamidase has been, in part hampered by the lack of a specific method to visualise this activity. We have developed a method to visualise the aryl acylamidase activity on cholinesterase in polyacrylamide gels. Results The o-nitroaniline liberated from o-nitroacetanilide by the action of aryl acylamidase activity on cholinesterases, in the presence of nitrous acid formed a diazonium compound. This compound gave an azo dye complex with N-(1-napthyl-ethylenediamine, which appeared as purple bands in polyacrylamide gels. Treating the stained gels with trichloroacetic acid followed by Tris-HCl buffer helped in fixation of the stain in the gels. By using specific inhibitors for acetylcholinesterase and butyrylcholinesterase, respectively, differential staining for the aryl acylamidase activities on butyrylcholinesterase and acetylcholinesterase in a sample containing both these enzymes has been demonstrated. A linear relationship between the intensity of colour developed and activity of the enzyme was obtained. Conclusions A novel method to visualise the aryl acylamidase activity on cholinesterases in polyacrylamide gels has been developed.

Boopathy Rathanam

2000-12-01

139

Synthesis and anticonvulsant activity of some novel 3-aryl amino/amino-4-aryl-5-imino-Delta2-1,2,4-thiadiazoline.  

Science.gov (United States)

A series of 3-aryl amino/amino-4-aryl-5-imino-Delta(2)-1,2,4-thiadiazoline have been synthesized using an appropriate synthetic route and characterized by elemental analyses and spectral data. The anticonvulsant activity of all the synthesized compounds was evaluated against maximal electroshock induced seizures (MES) and subcutaneous pentylenetetrazole (ScPTZ) induced seizure models in mice. The neurotoxicity was assessed using the rotorod method. All the test compounds were administered at doses of 30, 100, and 300 mg/kg body weight and the anticonvulsant activity was noted at 0.5 and 4 h time intervals after the drug administration. Some of the compounds were evaluated for the Phenobarbitone induced hypnosis potentiation test. Among the compounds tested, all except 2h showed protection from MES seizures, whereas only 3b was found to be active in the ScPTZ test. PMID:17624632

Gupta, Arun; Mishra, Pradeep; Kashaw, Sushil K; Jatav, Varsha; Stables, J P

2008-04-01

140

Synthesis and evaluation of 1-(quinoliloxypropyl)-4-aryl piperazines for atypical antipsychotic effect.  

Science.gov (United States)

A series of 1-(quinoliloxypropyl)-4-aryl-piperazines has been synthesized and the target compounds evaluated for atypical antipsychotic activity in apomorphine induced mesh climbing and stereotypic behaviour in mice. The 8-hydroxyquinoline ether derivative 14 has emerged as an important lead compound showing a potential atypical antipsychotic profile. Employing appropriate physicochemical properties, the similarity of the compounds was assessed with respect to some atypical antipsychotic drugs as clozapine, ketanserine, ziprasidone and risperidone. PMID:19398330

Bali, Alka; Malhotra, Sarika; Dhir, Himjyoti; Kumar, Anil; Sharma, Ajay

2009-06-01

 
 
 
 
141

Fast Method for Synthesis of Alkyl and Aryl-N-Methylnitrones  

Directory of Open Access Journals (Sweden)

Full Text Available A simple, fast, efficient and eco-friendly procedure was developed for the synthesis of alkyl and aryl-N-methylnitrones. The corresponding nitrones of aromatic aldehydes, aliphatic aldehydes and alicyclic carbonyl compounds were prepared from N-methylhydroxylamine hydrochloride and Na2CO3-Na2SO4 by simply grinding at room temperature without using solvent.

Yilmaz Yildirir

2011-08-01

142

Fast Method for Synthesis of Alkyl and Aryl-N-Methylnitrones  

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A simple, fast, efficient and eco-friendly procedure was developed for the synthesis of alkyl and aryl-N-methylnitrones. The corresponding nitrones of aromatic aldehydes, aliphatic aldehydes and alicyclic carbonyl compounds were prepared from N-methylhydroxylamine hydrochloride and Na2CO3-Na2SO4 by simply grinding at room temperature without using solvent.

2011-01-01

143

Towards aryl C-N bond formation in dynamic thin films.  

Science.gov (United States)

C-N bond forming reactions are important in organic chemistry. A thin film microfluidic vortex fluidic device (VFD) operating under confined mode affords N-aryl compounds from 2-chloropyrazine and the corresponding amine, without the need for a transition metal catalyst. PMID:24887640

Gandy, Michael N; Raston, Colin L; Stubbs, Keith A

2014-06-11

144

N-Aryl-benzimidazolones as novel small molecule HSP90 inhibitors  

Energy Technology Data Exchange (ETDEWEB)

We describe the development of a novel series of N-aryl-benzimidazolone HSP90 inhibitors (9) targeting the N-terminal ATP-ase site. SAR development was influenced by structure-based design based around X-ray structures of ligand bound HSP90 complexes. Lead compounds exhibited high binding affinities, ATP-ase inhibition and cellular client protein degradation.

Bruncko, Milan; Tahir, Stephen K.; Song, Xiaohong; Chen, Jun; Ding, Hong; Huth, Jeffrey R.; Jin, Sha; Judge, Russell A.; Madar, David J.; Park, Chang H.; Park, Cheol-Min; Petros, Andrew M.; Tse, Christin; Rosenberg, Saul H.; Elmore, Steven W. (Abbott)

2012-03-16

145

Nickel-catalysed aromatic Finkelstein reaction of aryl and heteroaryl bromides.  

Science.gov (United States)

A fast and efficient nickel-catalysed iodination reaction of aryl and heteroaryl bromides has been developed. The transformation was found to be general for a wide range of substrates and was used for the synthesis of iodo-PK11195, an imaging agent of Alzheimer's disease and iniparib, a compound used in the treatment of breast cancer. PMID:22422214

Cant, Alastair A; Bhalla, Rajiv; Pimlott, Sally L; Sutherland, Andrew

2012-04-25

146

Transition-metal-free C-arylation at room temperature by arynes.  

Science.gov (United States)

A facile, fluoride-induced transition-metal-free chemoselective ?-arylation of ?-dicarbonyl compounds (malonamide esters) at room temperature using aryne intermediates has been demonstrated. Selective mono- or diarylation and generation of a quaternary benzylic stereocenter have also been achieved. The methodology will be highly useful for the synthesis of a library of CNS depressant barbiturate drugs like Phenobarbital. PMID:22830485

Dhokale, Ranjeet A; Thakare, Pramod R; Mhaske, Santosh B

2012-08-01

147

Experimental and theoretical studies of selective thiol-ene and thiol-yne click reactions involving N-substituted maleimides.  

Science.gov (United States)

A combination of experimental and computational methods has been used to understand the reactivity and selectivity of orthogonal thiol-ene and thiol-yne ?click? reactions involving N-allyl maleimide (1) and N-propargyl maleimide (2). Representative thiols methyl-3-mercaptopropionate and ?-mercaptoethanol are shown to add exclusively and quantitatively to the electron poor maleimide alkene of 1 and 2 under base (Et3N) initiated thiol-Michael conditions. Subsequent radical-mediated thiol-ene or thiol-yne reactions can be carried out to further functionalize the remaining allyl or propargyl moieties in near quantitative yields (>95%). Selectivity, however, can only be achieved when base-initiated thiol-Michael reactions are carried out first, as radical-mediated reactions between equimolar amounts of thiol and N-substituted maleimides give complex mixtures of products. CBS-QB3 calculations have been used to investigate the energetics and kinetics of reactions between a representative thiol (methyl mercaptan) with N-allyl and N-propargyl maleimide under both base-initiated and radical-mediated conditions. Calculations help elucidate the factors that underlie the selective base-initiated and nonselective radical-mediated thiol-ene/yne reactions. The results provide additional insights into how to design selective radical-mediated thiol-ene/yne reactions. PMID:23924266

Stolz, Robert M; Northrop, Brian H

2013-08-16

148

PMR spectra and conformations of the cis and trans isomers of N-substituted 2,5-dimethyl-4-piperidones  

International Nuclear Information System (INIS)

The PMR spectra of mixtures of the trans and cis isomers of N-substituted 2,5-dimethyl-4-piperidones with three N-substituents (H, CH3, and CH2C6H5) and the hydrobromide of trans-2,5-dimethyl-4-piperidone were investigated at 250 and 360 MHz. The spectra of the major trans isomers were analyzed fully for the first time, and the relation between their PMR parameters and the stereochemical structure was investigated. It was shown that these isomers are predominantly represented by the 1e, 2e, and 5e conformations in the chair form of the piperidine ring. As a result of analysis of the PMR spectra of the minor cis isomers it was established that they are conformationally nonuniform and are characterized by a conformational equilibrium between the two chair forms Cl (1a, 2e, 5a) and C2 (1a, 2a, 5e), which is displaced toward C2 with increase in the size of the N-substituent. The populations and the differences in the energies were determined for these conformers

1986-04-10

149

Design, synthesis and biological assessment of novel N-substituted 3-(phthalimidin-2-yl)-2,6-dioxopiperidines and 3-substituted 2,6-dioxopiperidines for TNF-? inhibitory activity.  

Science.gov (United States)

Eight novel 2-(2,6-dioxopiperidin-3-yl)phthalimidine EM-12 dithiocarbamates 9 and 10, N-substituted 3-(phthalimidin-2-yl)-2,6-dioxopiperidines 11-14 and 3-substituted 2,6-dioxopiperidines 16 and 18 were synthesized as tumor necrosis factor-? (TNF-?) synthesis inhibitors. Synthesis involved utilization of a novel condensation approach, a one-pot reaction involving addition, iminium rearrangement and elimination, to generate the phthalimidine ring required for the creation of compounds 9-14. Agents were, thereafter, quantitatively assessed for their ability to suppress the synthesis on TNF-? in a lipopolysaccharide (LPS)-challenged mouse macrophage-like cellular screen, utilizing cultured RAW 264.7 cells. Whereas compounds 9, 14 and 16 exhibited potent TNF-? lowering activity, reducing TNF-? by up to 48% at 30 ?M, compounds 12, 17 and 18 presented moderate TNF-? inhibitory action. The TNF-? lowering properties of these analogs proved more potent than that of revlimid (3) and thalidomide (1). In particular, N-dithiophthalimidomethyl-3-(phthalimidin-2-yl)-2,6-dioxopiperidine 14 not only possessed the greatest potency of the analogs to reduce TNF-? synthesis, but achieved this with minor cellular toxicity at 30 ?M. The pharmacological focus of the presented compounds is towards the development of well-tolerated agents to ameliorate the neuroinflammation, that is, commonly associated with neurodegenerative disorders, epitomized by Alzheimer's disease and Parkinson's disease. PMID:21658960

Luo, Weiming; Yu, Qian-sheng; Salcedo, Isidro; Holloway, Harold W; Lahiri, Debomoy K; Brossi, Arnold; Tweedie, David; Greig, Nigel H

2011-07-01

150

Synthesis and antifungal activity of novel (1-aryl-2-heterocyclyl)ethylideneaminooxymethyl-substituted dioxolanes  

International Nuclear Information System (INIS)

A novel series of (1-aryl-2-heterocyclyl)ethylideneaminooxymethyl -substituted dioxolanes IIIa-n were synthesized by condensation of substituted 1,3-dioxolan-4-ylmethyl p-toluenesulfonates 4 with 1-(hydroxyimino)-1-aryl-2-heterocyclylethanes 5. Compounds IIIa-n were found to have effective in vitro antifungal activity when evaluated against the pathogenic fungi Candida albicans, Aspergillus flavus and Fusarium solani with MIC (minimum inhibitory concentration) values of 10 ?g-ml-1 for IIIa-I and 5 ?g-ml-1 for IIIm,n. (authors). 24 refs., 4 figs., 5 tabs

1995-01-01

151

Synthesis and antifungal activity of novel (1-aryl-2-heterocyclyl)ethylideneaminooxymethyl-substituted dioxolanes  

Energy Technology Data Exchange (ETDEWEB)

A novel series of (1-aryl-2-heterocyclyl)ethylideneaminooxymethyl -substituted dioxolanes IIIa-n were synthesized by condensation of substituted 1,3-dioxolan-4-ylmethyl p-toluenesulfonates 4 with 1-(hydroxyimino)-1-aryl-2-heterocyclylethanes 5. Compounds IIIa-n were found to have effective in vitro antifungal activity when evaluated against the pathogenic fungi Candida albicans, Aspergillus flavus and Fusarium solani with MIC (minimum inhibitory concentration) values of 10 {mu}g-ml{sup -1} for IIIa-I and 5 {mu}g-ml{sup -1} for IIIm,n. (authors). 24 refs., 4 figs., 5 tabs.

Baji, H.; Flammang, M.; Kimny, T.; Gasquez, F.; Compagnon, P.L.; Delcourt, A. [Dijon Univ., 21 (France)

1995-12-31

152

Synthesis of Dimethyl Aryl Acylsulfonium Bromides from Aryl Methyl Ketones in a DMSO-HBr System  

Directory of Open Access Journals (Sweden)

Full Text Available A new, simplified method for the synthesis of dimethyl aryl acylsulfonium salts has been developed. A series of dimethyl aryl acylsulfonium bromides were prepared by the reaction of aryl methyl ketones with hydrobromic acid and dimethylsulfoxide (DMSO. This sulfonium salt confirms that bromine production and the bromination reaction take place in the DMSO-HBr oxidation system. Whats more, it is also a key intermediate for the synthesis of arylglyoxals.

Zhiling Cao

2013-12-01

153

Synthesis and Pharmacological Evaluation of (6-Substituted 4-Oxo-4H-chromene-3 yl) methyl N-substituted Aminoacetates  

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A series of the title compounds were synthesized and characterized by spectral data. All the compounds were evaluated for in vitro antihistaminic activity by inhibition of isotonic contractions induced by histamine on isolated guinea pig ileum and the compound 6-k showed significant activity. A few compounds have also been screened for in vivo bronchodilatory activity. These compounds exhibited significant protection against histamine-induced convulsions in guinea pig at the dose of 50 ?mol.

Gajbhiye, Asmita; Mallareddy, V.; Achaiah, G.

2008-01-01

154

Synthesis and Pharmacological Evaluation of (6-Substituted 4-Oxo-4H-chromene-3 yl) methyl N-substituted Aminoacetates.  

Science.gov (United States)

A series of the title compounds were synthesized and characterized by spectral data. All the compounds were evaluated for in vitro antihistaminic activity by inhibition of isotonic contractions induced by histamine on isolated guinea pig ileum and the compound 6-k showed significant activity. A few compounds have also been screened for in vivo bronchodilatory activity. These compounds exhibited significant protection against histamine-induced convulsions in guinea pig at the dose of 50 mumol. PMID:20390097

Gajbhiye, Asmita; Mallareddy, V; Achaiah, G

2008-01-01

155

Synthesis and pharmacological evaluation of (6-substituted 4-Oxo-4 H -chromene-3 yl methyl N-substituted aminoacetates  

Directory of Open Access Journals (Sweden)

Full Text Available A series of the title compounds were synthesized and characterized by spectral data. All the compounds were evaluated for in vitro antihistaminic activity by inhibition of isotonic contractions induced by histamine on isolated guinea pig ileum and the compound 6-k showed significant activity. A few compounds have also been screened for in vivo bronchodilatory activity. These compounds exhibited significant protection against histamine-induced convulsions in guinea pig at the dose of 50 mol.

Gajbhiye Asmita

2008-01-01

156

Aryl hydrocarbon receptor and colitis.  

Science.gov (United States)

The aryl hydrocarbon receptor (AhR), a transcription factor activated by a large variety of natural and synthetic ligands, has recently become the object of great interest among researchers since it represents an important link between environment and immune-mediated pathologies. In this context, evidence has been accumulated to show that AhR is necessary for the maintenance/expansion of intraepithelial lymphocytes and interleukin-22-producing innate lymphoid cells in the gut and that defects in AhR-delivered signals may contribute to amplify gut tissue destructive immune-inflammatory reactions. We here review the available data supporting the role of AhR in the control of immune homeostasis in the gut and discuss whether and how AhR activators can help dampen inflammatory processes. PMID:23928874

Monteleone, Ivan; Pallone, Francesco; Monteleone, Giovanni

2013-11-01

157

Synthesis and antileishmanial activity of new 1-Aryl-1H-Pyrazole-4- carboximidamides derivatives  

Energy Technology Data Exchange (ETDEWEB)

Chemotherapy for leishmaniasis, diseases caused by protozoa of the genus Leishmania, remains inefficient in several treatments. So there is a need to search for new drugs. In this work, we have synthesized 1-aryl-1H-pyrazole-4-carboximidamides derivatives and evaluated antileishmanial activities in vitro, as well as cytotoxic effects. Structure-activity relationship (SAR) studies were carried out with all the compounds of the series. Compound 2 showed an activity profile that can be improved through medicinal chemistry strategies. (author)

Santos, Mauricio S. dos; Gomes, Adriana O.; Bernardino, Alice M.R.; Souza, Marcos C. de, E-mail: alicerolim@globo.co [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Programa de Pos-Graduacao em Quimica Organica; Khan, Misbahul A. [The Islamia University of Bahawalpur (Pakistan). Chemistry Dept.; Brito, Monique A. de [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Fac. de Farmacia. Lab. de Quimica Medicinal Computacional; Castro, Helena C.; Abreu, Paula A. [Universidade Federal Fluminense (LABioMol/GCM/UFF), Niteroi, RJ (Brazil). Inst. de Biologia. Lab. de Antibioticos, Bioquimica e Modelagem Molecular; Rodrigues, Carlos R. [Universidade Federal do Rio de Janeiro (ModMol/UFRJ), RJ (Brazil). Fac. de Farmacia. Lab. de Modelagem Molecular e QSAR; Leo, Rosa M.M. de; Leon, Leonor L.; Canto-Cavalheiro, Marilene M. [Fundacao Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, RJ (Brazil). Instituto Oswaldo Cruz. Lab. de Bioquimica de Tripanosomatideos

2011-07-01

158

Novel Scheme for Biosynthesis of Aryl Metabolites from l-Phenylalanine in the Fungus Bjerkandera adusta  

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Aryl metabolite biosynthesis was studied in the white rot fungus Bjerkandera adusta cultivated in a liquid medium supplemented with l-phenylalanine. Aromatic compounds were analyzed by gas chromatography-mass spectrometry following addition of labelled precursors (14C- and 13C-labelled l-phenylalanine), which did not interfere with fungal metabolism. The major aromatic compounds identified were benzyl alcohol, benzaldehyde (bitter almond aroma), and benzoic acid. Hydroxy- and methoxybenzylic ...

Lapadatescu, Carmen; Ginie?s, Christian; Le Que?re?, Jean-luc; Bonnarme, Pascal

2000-01-01

159

Synthesis and antileishmanial activity of new 1-Aryl-1H-Pyrazole-4- carboximidamides derivatives  

International Nuclear Information System (INIS)

Chemotherapy for leishmaniasis, diseases caused by protozoa of the genus Leishmania, remains inefficient in several treatments. So there is a need to search for new drugs. In this work, we have synthesized 1-aryl-1H-pyrazole-4-carboximidamides derivatives and evaluated antileishmanial activities in vitro, as well as cytotoxic effects. Structure-activity relationship (SAR) studies were carried out with all the compounds of the series. Compound 2 showed an activity profile that can be improved through medicinal chemistry strategies. (author)

2011-01-01

160

Pd(OAc)2/o-chloranil/M(OTf)n: a catalyst for the direct C-H arylation of polycyclic aromatic hydrocarbons with boryl-, silyl-, and unfunctionalized arenes.  

Science.gov (United States)

Pd(OAc)(2)/o-chloranil/M(OTf)(n) can effectively promote the C-H arylation of fluoranthene with arylboron compounds or arylsilanes. The reaction takes place with high regioselectivity at the C3 position of fluoranthene. Moreover, the new catalytic system allows the use of unfunctionalized arenes as coupling partners in the arylation of polycyclic aromatic hydrocarbons. PMID:22188556

Kawasumi, Katsuaki; Mochida, Kenji; Kajino, Tomonori; Segawa, Yasutomo; Itami, Kenichiro

2012-01-01

 
 
 
 
161

Arylations of substituted enamides by aryl iodides: regio- and stereoselective synthesis of (Z)-?-amido-?-arylacrylates.  

Science.gov (United States)

Arylations of substituted enamides by aryl iodides were achieved for the first time via an unusual PdCl2(COD)/Ag3PO4 catalytic system. A broad range of (Z)-?-amido-?-arylacrylates were prepared regio- and stereoselectively in a highly efficient manner. PMID:23947658

Gou, Quan; Deng, Bin; Zhang, Hongbin; Qin, Jun

2013-09-01

162

Discovery, synthesis, and evaluation of N-substituted amino-2(5H)-oxazolones as novel insecticides activating nicotinic acetylcholine receptors.  

Science.gov (United States)

N-Substituted amino-2(5H)-oxazolones A are a novel class of insecticides acting as nicotinic acetylcholine receptor (nAChR) agonists and show potent activity against hemipteran insect species. Here we report the discovery and preparation of this class of chemistry. Our efforts in SAR elucidation, biological activity evaluation, as well as mode-of-action studies are also presented. PMID:24703234

Zhang, Wenming; Barry, James D; Cordova, Daniel; McCann, Stephen F; Benner, Eric A; Hughes, Kenneth A

2014-05-01

163

Optimized Anti-pathogenic Agents Based on Core/Shell Nanostructures and 2-((4-Ethylphenoxy)ethyl)-N-(substituted-phenylcarbamothioyl)-benzamides  

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The purpose of this study was to design a new nanosystem for catheter surface functionalization with an improved resistance to Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 colonization and subsequent biofilm development. New 2-((4 ethylphenoxy)methyl)-N-(substituted-phenylcarbamothioyl)-benzamides were synthesized and used for coating a core/shell nanostructure. Their chemical structures were elucidated by NMR, IR and elemental analysis, being in agreement with the p...

Carmen Limban; Alexandru Mihai Grumezescu; Crina Saviuc; Georgeta Voicu; Gentiana Predan; Robert Sakizlian; Mariana Carmen Chifiriuc

2012-01-01

164

Solvent-Free Synthesis, DNA-Topoisomerase II Activity and Molecular Docking Study of New Asymmetrically N,N'-Substituted Ureas  

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A new series of asymmetrically N,N'-substituted ureas 2025 was prepared using solvent free conditions, which is an eco-friendly methodology, starting with Schiff bases derived from cinnamaldehyde and p-substituted anilines, which are subsequently submitted to reduction reactions that afford the corresponding asymmetric secondary amines. All of the intermediates were prepared using solvent free reactions, which were compared to traditional methodologies. All of the reactions requir...

2012-01-01

165

Synthesis, Photophysical, Electrochemical, Tumor-Imaging and Phototherapeutic Properties of Purpurinimide-N-substituted Cyanine Dyes Joined with Variable Length of Linkers  

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Purpurinimide methyl esters, bearing variable lengths of N-substitutions, were conjugated individually to a cyanine dye with a carboxylic acid functionality. The results obtained from in vitro and in vivo studies showed a significant impact of the linkers joining the phototherapeutic and fluorescence imaging moieties. The photosensitizer-fluorophore conjugate with a PEG linker showed the highest uptake in the liver, whereas the conjugate linked with two carbon units showed excellent tumor-ima...

2011-01-01

166

Research on antibacterial and antifungal agents. XIII. Synthesis and antimicrobial activity of 1-arylmethyl-4-aryl-1H-pyrrole-3-carboxylic acids.  

Science.gov (United States)

Several 1-arylmethyl-4-aryl-1H-pyrrole-3-carboxylic acid derivatives have been synthetized and tested as antifungal and antibacterial agents. Reaction between tosylmethylisocyanide (TosMIC) and beta-arylacrylic esters under basic conditions furnished 4-aryl-1H-pyrrole-3-carboxylic esters, which were then benzylated at 1 position. Alkaline hydrolysis of ethyl 1-arylmethyl-4-aryl-1H-pyrrole-3-carboxylates afforded the title compounds. All tested derivatives were found to be inactive as antifungal agents. Some of them showed appreciable antibacterial activities against Staphylococcus spp. PMID:2282118

Massa, S; Di Santo, R; Mai, A; Botta, M; Artico, M; Panico, S; Simonetti, G

1990-07-01

167

Selective arylation reactions of bismuth-transition metal salicylate complexes.  

Science.gov (United States)

Heterometallic bismuth-niobium or -tantalum salicylate complexes react with sodium tetraphenylborate to produce complexes in which one or more aryl groups have been transferred from boron to bismuth with the concomitant displacement of a eta(2)-salicylato ligand. When the previously reported Bi(2)Ta(2)(sal)(4)(Hsal)(4)(OEt)(4) (1) and BiTa(4)(mu-O)(4)(sal)(4)(Hsal)(3)(O(i)Pr)(4) (2) are treated with an alcoholic solution of NaBPh(4), the compounds [PhBi(Hsal)Ta(sal)(2)(OEt)(2) x EtOH](2) (3) and PhBiTa(4)(mu-O)(4)(Hsal)(2)(sal)(4)(OEt)(4) x CH(2)Cl(2) (4) are produced (sal = O(2)CC(6)H(4)-2-O(2-), Hsal = O(2)CC(6)H(4)-2-OH(-)). The core geometries of the heterometallic complexes are retained. However, if preparations of compound 1 are treated with NaBPh(4) without prior isolation of 1, [Ph(2)BiNb(sal)(2)(OMe)(2)](infinity) (5) is produced instead. This compound was characterized both as a solvent-free crystalline form and as one containing a lattice diethyl ether. The compound exhibits a polymeric chain structure that can be viewed as alternating [Ph(2)Bi](+) and [Nb(sal)(2)(OMe)(2)](-) units connected via bridging carboxylate groups. The arylation of the bismuth(III) center proceeds smoothly under mild conditions at room temperature, affording a new means for the mild functionalization of bismuth-transition metal heterometallic complexes. PMID:19537724

Stavila, Vitalie; Thurston, John H; Whitmire, Kenton H

2009-07-20

168

O-arylation versus C-arylation: copper-catalyzed intramolecular coupling of aryl bromides with 1,3-dicarbonyls.  

Science.gov (United States)

The copper-catalyzed intramolecular coupling of aryl bromides with 1,3-dicarbonyls via a six-membered ring closure was examined. With CuI (10 mol %) as the catalyst, N,N'-dimethylethylenediamine as the ligand, and Cs2CO3 as the base, the reactions of alpha-(2-bromobenzyl)-beta-keto esters in THF at refluxing temperature afforded the corresponding substituted 4H-1-benzopyrans in high yields via O-arylation. On the other hand, the reactions of delta-(2-bromophenyl)-beta-keto esters in refluxing dioxane led to the formation of 3,4-dihydronaphthalen-2(1H)-one derivatives via C-arylation. PMID:16901126

Fang, Yewen; Li, Chaozhong

2006-08-18

169

Targeting of Aryl Hydrocarbon Receptor-Mediated Activation of Cyclooxygenase-2 Expression by the Indole-3-Carbinol Metabolite 3,3?-Diindolylmethane in Breast Cancer Cells12  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ligands of the aryl hydrocarbon receptor (AhR) include the environmental xenobiotic 2,3,7,8 tetrachlorodibenzo(p)dioxin (TCDD), polycyclic aryl hydrocarbons, and the dietary compounds 3, 3?-diindolylmethane (DIM), a condensation product of indol-3-carbinol found in Brassica vegetables, and the phytoalexin resveratrol (RES). The AhR and its cofactors regulate the expression of target genes at pentameric (GCGTG) xenobiotic responsive elements (XRE). Because the activation of cyclooxygenase-2 ...

Degner, Stephanie C.; Papoutsis, Andreas J.; Selmin, Ornella; Romagnolo, Donato F.

2009-01-01

170

Room temperature, metal-free arylation of aliphatic alcohols.  

Science.gov (United States)

Diaryliodonium salts are demonstrated as efficient arylating agents of aliphatic alcohols under metal-free conditions. The reaction proceeds at room temperature within 90?min to give alkyl aryl ethers in good to excellent yields. Aryl groups with electron-withdrawing substituents are transferred most efficiently, and unsymmetric iodonium salts give chemoselective arylations. The methodology has been applied to the formal synthesis of butoxycaine. PMID:24808991

Ghosh, Raju; Lindstedt, Erik; Jalalian, Nazli; Olofsson, Berit

2014-04-01

171

Design, Synthesis and Antifibrotic Activities of Carbohydrate- Modified 1-(Substituted aryl-5-trifluoromethyl-2(1H Pyridones  

Directory of Open Access Journals (Sweden)

Full Text Available Pirfenidone, a pyridone compound, is an effective and novel antifibrotic agent. In this article, we describe the design, synthesis and activity evaluation of novel antifibrotic agents, 1-(substituted aryl-5-trifluoromethyl-2(1H pyridones modified with carbohydrate. Most of the title compounds exhibited comparable or better inhibitory activity than fluorofenidone. Notably, compound 19a demonstrated the highest cell-based inhibitory activity against NIH 3T3 (IC50 = 0.17 mM.

Lijian Tao

2012-01-01

172

Meta-arylation of calixarenes using organomercurial chemistry.  

Science.gov (United States)

A direct mercuration reaction combined with a subsequent Pd-catalyzed arylation was used to introduce the aryl moiety into the meta position of the calix[4]arene skeleton. The application of organomercurial intermediates thus allows the straightforward formation of meta-aryl-substituted derivatives representing a unique substitution pattern in calixarene chemistry. PMID:23863891

Slavk, Petr; Fldrov, Karolna; Dvo?kov, Hana; Eigner, Vclav; Lhotk, Pavel

2013-09-01

173

Synthesis and Antimicrobial Screening of Pyrazolo-3-Aryl Quinazolin-4(3H)ones.  

Science.gov (United States)

2-thio-3-aryl quinazolin-4(3H)one (1) was synthesized by reacting anthranilic acid with thiocarbamate salts of substituted aniline and carbon disulphide, which on reflux with excess of hydrazine hydrate to form 2-hydrazino quinazolin-4(3H)one derivatives (2). The reaction of (2) with variously substituted aryl aldehydes gave the corresponding hydrazones (3). Further, the cyclization of compound (3) in acetic anhydride gave tricyclic pyrazoloquinazolinones (4). All newly synthesized compounds have been tested for their antibacterial activity against gram +ve bacteria B. substilis, S. aureus and gram -ve bacteria E. coli, P. vulgaris. The species used for antifungal activity are Aspergillus niger and Phytophora. Introduction of -OCH3, -OH and -Cl groups to the heterocyclic frame work enhanced antibacterial and antifungal activities. PMID:21218064

Deshmukh, M B; Patil, S; Patil, S S; Jadhav, S D

2010-07-01

174

Synthesis and antimicrobial screening of pyrazolo-3-aryl quinazolin-4(3hones  

Directory of Open Access Journals (Sweden)

Full Text Available 2-thio-3-aryl quinazolin-4(3Hone (1 was synthesized by reacting anthranilic acid with thiocarbamate salts of substituted aniline and carbon disulphide, which on reflux with excess of hydrazine hydrate to form 2-hydrazino quinazolin-4(3Hone derivatives (2. The reaction of (2 with variously substituted aryl aldehydes gave the corresponding hydrazones (3. Further, the cyclization of compound (3 in acetic anhydride gave tricyclic pyrazoloquinazolinones (4. All newly synthesized compounds have been tested for their antibacterial activity against gram +ve bacteria B. substilis, S. aureus and gram -ve bacteria E. coli, P. vulgaris. The species used for antifungal activity are Aspergillus niger and Phytophora. Introduction of -OCH3, -OH and -Cl groups to the heterocyclic frame work enhanced antibacterial and antifungal activities.

Deshmukh M

2010-01-01

175

Synthesis and antibacterial activity of some novel 2-Aroylimino-3-aryl-thiazolidin-4-ones  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este trabalho relata uma sntese eficiente e regio-seletiva de algumas 2-aroylimino-3-aryl-thiazolidin-4-ones (2a-j) envolvendo a ciclizao de 1-aroyl-3-aryl tio-urias em meio bsico com cloreto de cloroacetila em dioxana. As estruturas foram confirmadas por dados espectroscpicos, anlises elemen [...] tares e, em um caso (2j), por dados de difrao de raios X tipo cristal nico. Os compostos foram testados in vitro quanto sua atividade antimicrobiana em relao a bactrias Gram positivas e Gram negativas. Os resultados revelaram uma atividade promissora desses compostos em relao aos microorganismos testados, comparando-se e, em alguns casos, at superando a atividade das drogas existentes. Abstract in english An efficient, regioselective synthesis of some 2-aroylimino-3-aryl-thiazolidin-4-ones (2a-j) involving base-catalyzed cyclization of 1-aroyl-3-aryl thioureas with chloroacetyl chloride in dioxane is reported. The structures were confirmed by spectroscopic data, elemental analyses and in one case (2j [...] ) by single crystal X-ray diffraction data. Compounds (2a-j) were assayed in vitro for their antimicrobial activity against Gram positive and Gram negative bacteria and were found to exhibit promising activity towards the tested microorganisms, comparable to and in some cases better than those of the standard drugs.

Saeed, Aamer; Abbas, Naeem; Flrke, Ulrich.

176

Synthesis and antibacterial activity of 5-aryl-2-[(alpha-chloro-alpha-phenylacetyl/alpha-bromopropionyl)amino]- 1,3,4-oxadiazoles and 2-[(5-aryl-1,3,4-oxadiazol-2-yl)imino]-5-phenyl/methyl-4-thiazolidinone s.  

Science.gov (United States)

Reaction of 5-aryl-2-amino-1,3,4-oxadiazoles (BI-VI), obtained by the oxydative cyclization of aromatic aldehyde semicarbazones (AI-VI), with alpha-chloro-alpha-phenylacetyl chloride and alpha-bromopropionyl bromide yielded 5-aryl-2-[(alpha-chloro-alpha-phenylacetyl)amino]-1,3,4-oxadiazoles (Ia-VIa) and 5-aryl-2-[(alpha-bromopropionyl)amino]-1,3,4-oxadiazoles (VIIa-XIIa), respectively. Furthermore, Ia-XIIa were refluxed with ammonium thiocyanate to give 5-phenyl/methyl-2-[(5-aryl-1,3,4-oxadiazol-2-yl)imino]-4-thiazo lidinones (It-XIIt). All compounds were tested for antibacterial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. They were all found to possess significant activity against S. aureus with MIC values ranging from 0.24 to 125 micrograms/ml. LD50 of compounds chosen as prototypes are estimated. PMID:9368708

Ate?, O; Kocabalkanli, A; Sani?, G O; Ekinci, A C; Vidin, A

1997-10-01

177

N-Substituted 5-Amino-6-methylpyrazine-2,3-dicarbonitriles: Microwave-Assisted Synthesis and Biological Properties  

Directory of Open Access Journals (Sweden)

Full Text Available In this work a series of 15 N-benzylamine substituted 5-amino-6-methyl-pyrazine-2,3-dicarbonitriles was prepared by the aminodehalogenation reactions using microwave assisted synthesis with experimentally set and proven conditions. This approach for the aminodehalogenation reaction was chosen due to its higher yields and shorter reaction times. The products of this reaction were characterized by IR, NMR and other analytical data. The compounds were evaluated for their antibacterial, antifungal and herbicidal activity. Compounds 3 (R = 3,4-Cl, 9 (R = 2-Cl and 11 (R = 4-CF3 showed good antimycobacterial activity against Mycobacterium tuberculosis (MIC = 6.25 g/mL. It was found that the lipophilicity is important for antimycobacterial activity and the best substitution on the benzyl moiety of the compounds is a halogen or trifluoromethyl group according to Craigs plot. The activities against bacteria or fungi were insignificant. The presented compounds also inhibited photosynthetic electron transport in spinach chloroplasts and the IC50 values of the active compounds varied in the range from 16.4 to 487.0 mol/L. The most active substances were 2 (R = 3-CF3, 3 (R = 3,4-Cl and 11 (R = 4-CF3. A linear dependence between lipophilicity and herbicidal activity was observed.

Ondrej Jandourek

2014-01-01

178

Substituent effect on IR, 1H and 13C NMR spectral data in n-(substituted phenyl)-2-cyanoacetamides: A correlation study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Linear free energy relationships (LFER) were applied to the IR, 1H and 13C NMR spectral data of N-(substituted phenyl)-2-cyanoacetamides. A variety of substituents were employed for phenyl substitution and fairly good correlations were obtained using the simple Hammett and the Hammett-Taft dual substituent parameter equations. The correlation results of the substituent induced 13C NMR chemical shifts (SCS) of the C1, C=O and N-H atom indicated different sensitivity with respect to elect...

Marinkovi? Aleksandar D.; Brki? Dominik; Martinovi? Jelena S.; Z?, Mijin Dus?an; Mil?i? Milo; Petrovi? Slobodan D.

2013-01-01

179

Palladium-catalyzed CN and CO bond formation of N-substituted 4-bromo-7-azaindoles with amides, amines, amino acid esters and phenols  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Simple and efficient procedures for palladium-catalyzed cross-coupling reactions of N-substituted 4-bromo-7-azaindole (1H-pyrrole[2,3-b]pyridine), with amides, amines, amino acid esters and phenols through CN and CO bond formation have been developed. The CN cross-coupling reaction of amides, amines and amino acid esters takes place rapidly by using the combination of Xantphos, Cs2CO3, dioxane and palladium catalyst precursors Pd(OAc)

Rajendra Surasani; Dipak Kalita; Dhanunjaya Rao, A. V.; Chandrasekhar, K. B.

2012-01-01

180

Preparation of Peptide p-Nitroanilides using an Aryl Hydrazine Solid Support  

Energy Technology Data Exchange (ETDEWEB)

Peptide p-nitroanilides are useful compounds for studying protease activity, however the poor nucleophilicity of p-nitroaniline makes their preparation difficult. We describe a new efficient approach for the Fmoc-based synthesis of peptide p-nitroanilides using an aryl hydrazine resin. Mild oxidation of the peptide hydrazide resin yields a highly reactive acyl diazene, which efficiently reacts with weak nucleophiles. We have prepared several peptide p-nitroanilides, including substrates for the Lethal Factor protease from B. anthracis.

Kwon, Y; Welsh, K; Mitchell, A R; Camarero, J A

2004-08-05

 
 
 
 
181

REDUCTION OF VITELLOGENIN SYNTHESIS BY AN ARYL HYDROCARBON RECEPTOR AGONIST IN THE WHITE STURGEON (ACIPENSER TRANSMONTAMUS)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Migrating white sturgeon (Acipenser transmontamus) may be subject to agricultural, municipal, and industrial wastewater effluents that likely contain different classes of endocrine-disrupting contaminants. Concern is mounting about the negative effects of environmental estrogens on fish reproduction; however, in environmental mixtures, the affects from estrogenic compounds may be suppressed by aryl hydrocarbon receptor (AhR) ligands. Indeed, reductions in 17?-estradiolinduced (0.01 and 1 ...

Palumbo, Amanda J.; Denison, Michael S.; Doroshov, Serge I.; Tjeerdema, Ronald S.

2009-01-01

182

Diaryliodonium Salts : Development of Synthetic Methodologies and?-Arylation of Enolates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis describes novel reaction protocols for the synthesis of diaryliodonium salts and also provides an insight to the mechanism of ?-arylation of carbonyl compounds with diaryliodonium salts. The first chapter gives a general introduction to the field of hypervalent iodine chemistry, mainly focusing on recent developments and applications of diaryliodonium salts. Chapter two describes the synthesis of electron-rich to electron-poor diaryliodonium triflates, in moderate to excellent ...

Bielawski, Marcin

2011-01-01

183

Novel macrocyclic molecules based on 12a-N substituted 16-membered azalides and azalactams as potential antifungal agents.  

Science.gov (United States)

Novel macrocyclic molecules comprising sulfonyl and acyl moiety at the position N-12a of 16-membered azalides (6a-n) and azalactams (10a-r) scaffold were synthesized from cyclododecanone 1 as starting material via 5 steps and 4 steps, respectively. The antifungal activity of these compounds against Sclerotinia sclerotiorum, Pyricularia oryzae, Botrytis cinerea, Rhizoctonia solani and Phytophthora capsici were evaluated and found that compounds possessing ?-exomethylene (6c, 6d, 6e and 6g) showed antifungal activity comparable to commercial fungicide Chlorothalonil against P. oryzae and compounds possessing p-chlorobenzoyl exhibited enhanced antifungal activity than those with other substituents against S.sclerotiorum, P.oryzae, and B.cinerea. These findings suggested that the ?-exomethylene and p-chlorobenzoyl may be two potential pharmacological active groups with antifungal activities. PMID:24469079

Wang, Xiaolei; Zhang, Shun; Pang, Yanlong; Yuan, Huihui; Liang, Xiaomei; Zhang, Jianjun; Wang, Daoquan; Wang, Mingan; Dong, Yanhong

2014-02-12

184

Novel Synthesis and Anti-HIV-1 Activity of 2-Arylthio-6-benzyl-2,3-dihydro-1H-pyrimidin-4-ones (Aryl S-DABOs)  

DEFF Research Database (Denmark)

The synthesis and the anti-HIV-1 activity of a series of 2-arylthio-6-benzyl-2,3-dihydro-1H-pyrimidin-4-ones (aryl S-DABOs) are reported. These compounds were synthesized via a coupling reaction of the corresponding 6-benzyl-2-thiouracils with aryl iodides in the presence of neocuproine hydrate, copper(I) iodide, and sodium tert-butoxide. Target compounds showed moderate activity against HIV-1.

Aly, Youssef L.; Pedersen, Erik Bjerreg.

2007-01-01

185

[The anti-arrhythmia activity of new dicyclohexylamide derivatives of N-substituted alpha-aminocarboxylic acids].  

Science.gov (United States)

Experiments on arrhythmia models showed a high antiarrhythmic activity of new derivatives of dicyclohexylamides of N-replaced alpha-aminocarbonic acids. The new compounds surpassed in intensity and duration of the antiarrhythmic effect the standard agents with classes I and III antiarrhythmic activity. In doing so they raise myocardial electrical stability and prevent sudden development of ventricular fibrillation. According to the mechanism of the antiarrhythmic activity, the new compounds may be related to antiarrhythmic agents possessing the properties of classes I and III. PMID:10513331

Berdiaev, S U; Paliani-Katsitadze, N Sh; Turilova, A I; Kaverina, N V; Likhosherstov, A M; Lebedeva, A S; Ogurtsov, V A

1999-01-01

186

Aryl Polyphosphonates: Useful Halogen-Free Flame Retardants for Polymers  

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Full Text Available Aryl polyphosphonates (ArPPN have been demonstrated to function in wide applications as flame retardants for different polymer materials, including thermosets, polycarbonate, polyesters and polyamides, particularly due to their satisfactory thermal stability compared to aliphatic flame retardants, and to their desirable flow behavior observed during the processing of polymeric materials. This paper provides a brief overview of the main developments in ArPPN and their derivatives for flame-retarding polymeric materials, primarily based on the authors research work and the literature published over the last two decades. The synthetic chemistry of these compounds is discussed along with their thermal stabilities and flame-retardant properties. The possible mechanisms of ArPPN and their derivatives containing hetero elements, which exhibit a synergistic effect with phosphorus, are also discussed.

Li Chen

2010-10-01

187

Tetrakis(triethyl phosphite)(nickel(O)): catalyst for the reactions of aryl halides with trialkyl phosphites  

International Nuclear Information System (INIS)

The authors report the discovery of a new catalyst for the reactions of aryl halides with trialkyl phosphites, namely, tetrakis(triethyl phosphite)Ni(O). They suppose that catalysis by the Ni(O) complex consists of two stages. The first is the oxidative addition of the aryl halide to the Ni(O) complex. The second is reductive elimination with the regeneration of the catalyst. The proposed scheme is confirmed by the results of the methods of molecular spectroscopy. The formation of a tetrahedral paramagnetic complex is characterized by a weakening and broadening of the 31P signal and by a downfield shift of the compounds by 20-60 ppm

1986-10-10

188

Synthesis of 3-aryl-4-methyl-1,2-benzenedisulfonimides, new chiral Brnsted acids. A combined experimental and theoretical study  

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We have recently reported the use, in catalytic amounts, of 1,2-benzenedisulfonimide as a safe Brnsted acid in some acid-catalyzed organic reactions. With the design of new and chiral acid organocatalysts with the structure of 1,2-benzenedisulfonimide in mind, we herein propose a synthesis of 1,2-benzenedisulfonimide derivatives bearing an aryl group in the 3-position with good overall yields. The chirality of these compounds is due to the hindered rotation of the aryl group (atropisomerism...

2011-01-01

189

Design, synthesis and investigation on the structure-activity relationships of N-substituted 2-aminothiazole derivatives as antitubercular agents.  

Science.gov (United States)

Tuberculosis (TB) is one of the deadliest infectious diseases of all times, and its recent resurgence is a supreme matter of concern. Co-infection with HIV and, in particular, the continuous isolation of new resistant strains, makes the discovery of novel anti-TB agents a strategic priority. The research of novel agents should be driven by the accessibility of the synthetic procedure and, in particular, by the lack of cross-resistance with the drugs already marketed. Moreover, in order to shorten the duration of the therapy, and therefore decrease the rate of resistance, these molecules should be active also against the nonreplicating persistent form (NRP-TB) of the infection. The availability of an in-house small library of compounds prompted us to investigate their anti-TB activity. Two compounds, embodying a2-aminothiazole scaffold, were found to possess a certain inhibitory activity toward Mycobacterium tuberculosis H37Rv, and therefore a medicinal chemistry campaign was initiated in order to increase the activity of the hit compounds and, especially, construct a plausible body of structure-activity relationships. The potency of the hit compound was successfully improved, and, much more importantly, some of the molecules synthesized were found to be active toward the persistent phenotype, and, also, toward a panel of resistant strains. These findings encourage further investigations around this interesting antitubercular chemotype. PMID:24333612

Pieroni, Marco; Wan, Baojie; Cho, Sanghyun; Franzblau, Scott G; Costantino, Gabriele

2014-01-24

190

Synthesis of fluorescent (benzyloxycarbonylamino)(aryl)methylphosphonates  

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Summary The synthesis of a library of structurally variable aromatic esters of (benzyloxycarbonylamino)(aryl)methylphosphonic acids is described by means of the Oleksyszyn reaction. The library was enlarged by the application of a SuzukiMiayra approach and by preparation of mixed esters.

Gorniak, Michal Gorny vel; Czernicka, Anna; Mlynarz, Piotr; Balcerzak, Waldemar

2014-01-01

191

Synthesis of aryl halides via organoborane chemistry  

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A method for the rapid synthesis of a variety of substituted aryl halides by the reaction of organoboranes with halide ions in the presence of chloramine-T is described in detail. The products were purified by column chromatography on silica gel using a mixture of petroleum ether-ethyl acetate as eluent.

Kabalka, G.W.; Sastry, K.A.R.; Sastry, U.; Somayaji, V.

1982-01-01

192

Fluoroalkylation of aryl ether perfluorocyclobutyl polymers  

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Post functionalization of aryl ether perfluorocyclobutyl (PFCB) polymers with fluoroalkyl side chains was accomplished with Umemoto's FITS reagents. The fluoroalkylated PFCB polymers (20 % functionalized) showed increases in both hydrophobicity and oleophobicity. Static contact angle for hexadecane was increased after fluoroalkylation from 0 to greater than 30 for the two PFCB polymers tested. Increased oil repellency makes these materials potential candidates for various coatings applica...

Ligon, Clark; Ameduri, Bruno; Boutevin, Bernard; Smith, Dennis

2008-01-01

193

Differential modulation of GABAA receptor function by aryl pyrazoles.  

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Several aryl pyrazoles characterized by a different molecular structure (flexible vs constrained), but chemically related to rimonabant and AM251, were tested for their ability to modulate the function of recombinant ?1?2?2L GABAA receptors expressed in Xenopus laevis oocytes. The effects of 6Bio-R, 14Bio-R, NESS 0327, GP1a and GP2a (0.3-30?M) were evaluated using a two-electrode voltage-clamp technique. 6Bio-R and 14Bio-R potentiated GABA-evoked Cl(-) currents. NESS 0327, GP1a and GP2a did not affect the GABAA receptor function, but they acted as antagonists of 6Bio-R. Moreover, NESS 0327 inhibited the potentiation of the GABAA receptor function induced by rimonabant. The benzodiazepine site seems to participate in the action of these compounds. In fact, flumazenil antagonized the potentiation of the GABAA receptor induced by 6Bio-R, and NESS 0327 reduced the action of lorazepam and zolpidem. On the contrary, NESS 0327 did not antagonize the action of "classic" GABAergic modulators (propanol, anesthetics, barbiturates or steroids). In ?1?2 receptors 6Bio-R potentiated the GABAergic function, but flumazenil was still able to antagonize the potentiation induced by 6Bio-R. Aryl pyrazole derivatives activity at the GABAA receptor depends on their molecular structure. These compounds bind to both an ??? binding site, and to an ??? site which do not require the ? subunit and that may provide structural leads for drugs with potential anticonvulsant effects. PMID:24704372

Mascia, Maria Paola; Ledda, Giovanni; Orr, Alessandro; Marongiu, Alessandro; Loriga, Giovanni; Maciocco, Elisabetta; Biggio, Giovanni; Ruiu, Stefania

2014-06-15

194

Production of p-acetaminophenol by whole-cell catalysis using Escherichia coli overexpressing bacterial aryl acylamidase.  

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Aryl acylamidase (EC 3.5.1.13, AAA) acts on the amide bond between aryl and acyl groups. Whole cells of Escherichia coli overexpressing a novel bacterial AAA synthesized p-acetaminophenol (p-AAP) from p-aminophenol (p-AP, aryl compound) and acetate (acyl donor). Optimum conditions were pH 5.5 and 35C with 100 mM p-AP and 600 mM sodium acetate in 100 mM sodium phosphate buffer including 1% (v/v) Triton X-100 for 60 h. 13.1 g p-AAP l(-1) was produced with a conversion yield of 87%. PMID:22130742

Ko, Hyeok-Jin; Bang, Won-Gi; Kim, Kyoung Heon; Choi, In-Geol

2012-04-01

195

Cloning and heterologous expression of two aryl-aldehyde dehydrogenases from the white-rot basidiomycete Phanerochaete chrysosporium  

International Nuclear Information System (INIS)

We identified two aryl-aldehyde dehydrogenase proteins (PcALDH1 and PcALDH2) from the white-rot basidiomycete Phanerochaete chrysosporium. Both PcALDHs were translationally up-regulated in response to exogenous addition of vanillin, one of the key aromatic compounds in the pathway of lignin degradation by basidiomycetes. To clarify the catalytic functions of PcALDHs, we isolated full-length cDNAs encoding these proteins and heterologously expressed the recombinant enzymes using a pET/Escherichia coli system. The open reading frames of both PcALDH1 and PcALDH2 consisted of 1503 nucleotides. The deduced amino acid sequences of both proteins showed high homologies with aryl-aldehyde dehydrogenases from other organisms and contained ten conserved domains of ALDHs. Moreover, a novel glycine-rich motif 'GxGxxxG' was located at the NAD+-binding site. The recombinant PcALDHs catalyzed dehydrogenation reactions of several aryl-aldehyde compounds, including vanillin, to their corresponding aromatic acids. These results strongly suggested that PcALDHs metabolize aryl-aldehyde compounds generated during fungal degradation of lignin and various aromatic xenobiotics.

2010-04-09

196

SYNTHESIS AND BIOLOGICAL EVALUATION OF NOVEL N-(SUBSTITUTED BENZYL-N-PROPYL-2-(TRICHLOROMETHYL QUINAZOLIN-4-AMINE DERIVATIVES AS CYTOTOXIC AGENTS Synthese und biologische Evaluierung neuartiger N-(SUBSTITUIERTEN BENZYL-N-propyl-2-(trichlormethyl chinazolin-4-amin DERIVATE ALS zytotoxischen Wirkstoffen  

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Full Text Available A series of novel 2-trichloromethyl quinazoline derivatives bearing tertiary amine group at the 4th position were synthesized and evaluated for their in-vitro cytotoxicity against human lung carcinoma cell line A549 and Human colorectal adernocarcinoma cell line HT-29 by MTT assay method. All the molecules were designed on the basis of Hydrogen bond acceptor, trichloro methyl group and presence of aromatic ring. The targeted compounds (8a-o were synthesized from 4-chloro-2-(trichloromethyl quinazolines and N-(substituted benzyl propan-1-amines in alcoholic medium under reflux for 15-18 h. Compounds 8f and 8l exhibited highest cytotoxicity against human lung carcinoma A549 cell line (IC50 7.5 and 6.8 ?G and human colon carcinoma HT-29 cell line (IC50 8.2 and 8.0 ?G among the derivatives

Maneesh Kumar Srivastav, N. Srinivasulu, S. M. Shantakumar

2013-01-01

197

Synthesis of 2,3-Dioxo-5-(substitutedarylpyrroles and Their 2-Oxo-5-aryl-3-hydrazone Pyrrolidine Derivatives  

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Full Text Available Some novel2,3-dioxo-5-(substitutedarylpyrroles have been synthesized. Among these, pyrrolidine compound 1b was converted to 2,3-dioxo-5-aryl pyrrolidine 2b. Finally a set of hydrazone derivatives was obtained from the reaction of 2b with various hydrazine salts. The structures of all the new synthesized compounds were confirmed by elemental analyses, IR and 1H-NMR spectra.

A. S. Hamzah

2009-01-01

198

Synthesis and Bioactivity Evaluation of New 6-Aryl-5-cyano Thiouracils as Potential Antimicrobial and Anticancer Agents  

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Several novel 6-aryl-5-cyano thiouracil derivatives were synthesized and explored for their activities as antibacterial, antifungal and anticancer agents. The antimicrobial evaluation revealed that compounds 7b and 7c possessed superior antibacterial activity against the Gram positive bacteria S. aureus and B. subtilis compared to the reference drug amoxicillin. Moreover, compound

Azza Taher Taher; Sahar Mahmoud Abou-Seri

2012-01-01

199

DNA binding, nuclease activity, DNA photocleavage and cytotoxic properties of Cu(II) complexes of N-substituted sulfonamides.  

Science.gov (United States)

Ternary copper(II) complexes [Cu(NST)2(phen)] (1) and [Cu(NST)2(NH3)2]H2O (2) [HNST=N-(4,5-dimethylthiazol-2-yl)naphthalene-1-sulfonamide] were prepared and characterized by physico-chemical techniques. Both 1 and 2 were structurally characterized by X-ray crystallography. The crystal structures show the presence of a distorted square planar CuN4 geometry in which the deprotonated sulfonamide, acting as monodentate ligand, binds to the metal ion through the thiazole N atom. Both complexes present intermolecular ?-? stacking interactions between phenanthroline rings (compound 1) and between naphthalene rings (compound 2). The interaction of the complexes with CT DNA was studied by means of thermal denaturation, viscosity measurements and fluorescence spectroscopy. The complexes display good binding propensity to the calf thymus DNA giving the order: 1>2. Complex 1, which has a higher capability for binding to DNA, showed better nuclease activity than 2 in the presence of ascorbate/H2O2. Both the kinetics and the mechanism of the DNA cleavage reaction were investigated. Furthermore, complex 1 showed efficient photo-induced DNA cleavage activity on irradiation with UV light in the absence of any external reagent. The UV light induced DNA cleavage follows a photo-redox pathway with generation of hydroxyl radicals as reactive species. In addition, the cytotoxic properties of both complexes (1 and 2) were evaluated in human cancer cells (HeLa, Caco-2 and MDA-468). The low IC50 values, in particular those against Caco-2, have indicated that the compounds can be considered as promising chemotherapeutic agents. PMID:23384854

Garca-Gimnez, Jos Luis; Hernndez-Gil, Javier; Martnez-Ruz, Aloma; Castieiras, Alfonso; Liu-Gonzlez, Malva; Pallard, Federico V; Borrs, Joaqun; Alzuet Pia, Gloria

2013-04-01

200

Syntheses of [/sup 18/F] aryl fluorides by fluorination of aryltrimethylsilanes or arylpentafluorosilicates with [/sup 18/F]F/sub 2/ or [/sup 18/F]CH/sub 3/CO/sub 2/F  

International Nuclear Information System (INIS)

F-18 Aryl fluorides are the important intermediates for the syntheses of F-18 labeled radiopharmaceuticals. F-18 Labeled aryl fluorides have been synthesized either from [/sup 18/F]F/sub 2/ or [/sup 18/F]fluoride. The authors report here the syntheses of [/sup 18/F]aryl fluorides by fluorination of aryltrimethylsilanes (1) or arylpentaflurorsilicates (2) with [/sup 18/F]F/sub 2/ or [/sup 18/F]CH/sub 3/CO/sub 2/F. Fluorination of compounds (1) with either [/sup 18/F]F/sub 2/ or [/sup 18/F]CH/sub 3/CO/sub 2/F give the corresponding aryl fluorides (3) and the aryltrimethylsilyl fluorides (4) in 2-10% yields depending on the reaction conditions. Compounds (2) and (3) can easily be separate by HPLC or GLC. Treatment of compounds (4) with HClO/sub 4/-MeOH (1:1) give the corresponding desilylated compounds (3underscore). Fluorination of compounds (2) with [/sup 18/F]CH/sub 3/CO/sub 2/F give the corresponding aryl fluorides (3) in 10-20% yield. The yields of compounds (3) and (4) depend on the reaction conditions. Lower temperature (-76"0C in freon vs 25"0C in CH/sub 3/CO/sub 2/H) favors the formation of aryl fluorides, [/sup 18/F]F/sub 2/ gives a better yield of aryl fluorides than with [/sup 18/F]CH/sub 3/CO/sub 2/F, and the electron-withdrawing groups are in favor of aryl fluoride formations. This method thus provides an alternative route to F-18 labeled radiopharmaceuticals such as p-/sup 18/F]fluorohippuric acid which is otherwise difficult to prepare, and other F-18 labeled neuroleptics

1984-06-05

 
 
 
 
201

Opioids and Efflux Transporters. 1. P-Glycoprotein Substrate Activity of N-Substituted Analogs of Meperidine.  

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P-Glycoprotein (P-gp) is an efflux transporter which is up-regulated at the blood brain barrier in both morphine and oxycodone tolerant rats. Numerous studies have shown that many clinically employed opioid analgesics are substrates for P-gp, suggesting that up-regulation of P-gp may contribute to the development of central tolerance to opioids. The studies herein focus on the development of SAR for P-gp substrate activity in the meperidine series of compounds, and show that a meperidine anal...

Mercer, Susan L.; Cunningham, Christopher W.; Hassan, Hazem; Eddington, Natalie D.; Coop, Andrew

2007-01-01

202

Skeletal diversification via heteroatom linkage control: preparation of bicyclic and spirocyclic scaffolds from N-substituted homopropargyl alcohols.  

Science.gov (United States)

The discovery and application of a new branching pathway synthesis strategy that rapidly produces skeletally diverse scaffolds is described. Two different scaffold types, one a bicyclic iodo-vinylidene tertiary amine/tertiary alcohol and the other, a spirocyclic 3-furanone, are each obtained using a two-step sequence featuring a common first step. Both scaffold types lead to intermediates that can be orthogonally diversified using the same final components. One of the scaffold types was obtained in sufficiently high yield that it was immediately used to produce a 97-compound library. PMID:23510238

Painter, Thomas O; Bunn, Jonathon R; Schoenen, Frank J; Douglas, Justin T; Day, Victor W; Santini, Conrad

2013-04-19

203

FERRIC ION-SPECIFIC SEQUESTERING AGENTS. 7. SYNTHESIS, IRON EXCHANGE KINETICS, AND STABILITY CONSTANTS OF N-SUBSTITUTED, SULFONATED CATECHOYLAMIDE ANALOGUES OF ENTEROBACTIN.  

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For treatment of chronic iron overload (as occurs in Cooley's anemia), ferric ion sequestering agents with specific properties are necessary. Two analogues of enterobactin [a microbial chelating agent with the greatest stability constant known for an Fe(III) complex] are reported which exhibit: i) hydrolytic stability; ii) water solubility; iii) N-substitution to block peptidase hydrolysis. The first compound, N,N',N"- trimethyl-N,N',N"-tris(2,3-dihydroxysulfobenzoyl)1,3,5-triaminomethyl- benzene, [Me{sub 3}MECAMS, 6] was prepared from the amide of trimesloyl chloride (1) and MeNH{sub 2}. The resulting amide was reduced to the triamine (3) and converted in three steps to the final product 6 in 6% overall yield. The proton-dependent formation constant (log K*) for the reaction: Fe{sup 3+} + H{sub 3}L{sup 6-} = FeL{sup 6-} + 3H{sup +} is 4.87, which gives an equilibrium concentration of [Fe{sup 3+}] at pH 7.4 of 2 x 10{sup -27} M for 10{sup -5} M L (6) and 10{sup -6} M total Fe{sup 3+}. The estimated formation constant (log {beta}{sub 110}) is 40. At low pH the FeL{sup 6-} complex undergoes a series of three, one-proton reactions which probably gives a tris-salicylate complex formed by the carbonyl and ortho-catechol oxygen of the 2,3~dihydroxybenzoyl units (the same reaction that occurs with ferric enterobactin). After six hours in the presence of 6 mM ascorbate, Me{sub 3}MECAMS (6.0 mM) removed 3.7% of the ferric ion initially sequestered by the iron storage protein, ferritin. The human iron transport protein transferrin goves up iron to Me{sub 3}MECAMS with a pseudo first-order rate constant of 1.9 x 10{sup -3}min{sup -1} (ligand concentration 2 X 10{sup -4} M). This rate is comparable to that of enterobactin and other catechoyl amide sequestering agents. and greatly exceeds that of desferrioxamine B (Desferal{reg-sign}). the current drug of choice in treating iron overload. Two related compounds have been prepared in which the catechol ring is attached to the amide nitrogen through a methylene group, with amide formation with an acetyl group. In N,N',N"-triacetyl-N,N' ,N"-tris(2,3- dihydroxysulfobenzoyl) -N,N',N"-triaminomethylbenzene [NAcMECAMS, 111... and its unsulfonated precursor, the amide linkage of the catechoyl amides such as Me{sub 3}MECAMS (6) has been shifted from an endo position relative to the benzene and catechol rings to an exo position in which the amide carbonyl is not conjugated with the catechol ring and cannot form a stable chelate ring in conjunction with a catechol oxygen. The preparation of 11 and 10 proceeded from the previously described precursor of TRIMCAM, 7. borane reduction to the tri.amine 8, and amide formation with acetyl chloride to 9, followed by deprotection of the catechol oxygens with BBr{sub 3}/CH{sub 2}Cl{sub 2} to give 10. Sulfonation of 10 to NAcMECAMS, 11, is carried out in fuming sulfuric acid. In comparison with Me{sub 3}MECAMS, the protonation of NAcMECAMS (11) proceeds by an initial two-proton step in contrast to the one-proton reactions typical of the catechoyl amides, which can form a salicylate mode of coordination involving the amide carbonyl group. Also as a result of the removal of the carbonyl group from conjugation with the catechol ring, the acidity of NAcMECAMS (11) is less than Me{sub 3}MECAMS (6). While the estimated log {beta{sub 110} is approximately the same as for Me{sub 3}MECAMS (40). the effective formation constant (log K*) and pM.(- log [Fe{sub aq}{sup 3+}] ) values are lower (4.0 and 25.0, respectively).

Pecoraro, Vincent L.; Weitl, Frederick L.; Raymond, Kenneth N.

1980-10-01

204

C(aryl-O Bond Formation from Aryl Methanesulfonates via Consecutive Deprotection and SNAr Reactions with Aryl Halides in an Ionic Liquid  

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Full Text Available An efficient K3PO4-mediated synthesis of unsymmetrical diaryl ethers using the ionic liquid [Bmim]BF4 (1-butyl-3-methylimidazolium tetrafluoroborate as solvent has been developed. The procedure involves consecutive deprotection of aryl methane-sulfonates and a nucleophilic aromatic substitution (SNAr with activated aryl halides.

Yang Chen

2007-04-01

205

C(aryl)-O Bond Formation from Aryl Methanesulfonates via Consecutive Deprotection and SNAr Reactions with Aryl Halides in an Ionic Liquid  

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An efficient K3PO4-mediated synthesis of unsymmetrical diaryl ethers using the ionic liquid [Bmim]BF4 (1-butyl-3-methylimidazolium tetrafluoroborate) as solvent has been developed. The procedure involves consecutive deprotection of aryl methane-sulfonates and a nucleophilic aromatic substitution (SNAr) with activated aryl halides.

Hui Xu; Yang Chen

2007-01-01

206

Aryl biphenyl-3-ylmethylpiperazines as 5-HT7 receptor antagonists.  

Science.gov (United States)

The 5-HT7 receptor (5-HT7 R) is a promising therapeutic target for the treatment of depression and neuropathic pain. The 5-HT7 R antagonist SB-269970 exhibited antidepressant-like activity, whereas systemic administration of the 5-HT7 R agonist AS-19 significantly inhibited mechanical hypersensitivity and thermal hyperalgesia. In our efforts to discover selective 5-HT7 R antagonists or agonists, aryl biphenyl-3-ylmethylpiperazines were designed, synthesized, and biologically evaluated against the 5-HT7 R. Among the synthesized compounds, 1-([2'-methoxy-(1,1'-biphenyl)-3-yl]methyl)-4-(2-methoxyphenyl)piperazine (28) was the best binder to the 5-HT7 R (pKi =7.83), and its antagonistic property was confirmed by functional assays. The selectivity profile of compound 28 was also recorded for the 5-HT7 R over other serotonin receptor subtypes, such as 5-HT1 R, 5-HT2 R, 5-HT3 R, and 5-HT6 R. In a molecular modeling study, the 2-methoxyphenyl moiety attached to the piperazine ring of compound 28 was proposed to be essential for the antagonistic function. PMID:24039134

Kim, Jeeyeon; Kim, Youngjae; Tae, Jinsung; Yeom, Miyoung; Moon, Bongjin; Huang, Xi-Ping; Roth, Bryan L; Lee, Kangho; Rhim, Hyewhon; Choo, Il Han; Chong, Youhoon; Keum, Gyochang; Nam, Ghilsoo; Choo, Hyunah

2013-11-01

207

Palladium-Catalyzed Highly Regioselective C-3 Arylation of Imidazo[1,5-a]pyridine  

Science.gov (United States)

A direct palladium-catalyzed highly regioselective C-3 arylation of imidazo[1,5-a]pyridine with aryl bromides has been developed. This reaction is quite general with respect to the aryl or hetaryl bromide.

Huang, Chunhui; Giokaris, Alexandros; Gevorgyan, Vladimir

2013-01-01

208

N-Heterocyclic Carbene Complexes in Arylation Reactions other than Cross-couplings  

Science.gov (United States)

This chapter highlights the use of N-heterocyclic carbenes as supporting ligands in arylation reactions different than the more common cross-coupling reactions, including C-F bond activation, catalytic arylation, homocoupling, direct arylation and oxidative Heck reactions.

Berini, Christophe; Navarro, Oscar

209

Synthesis and pharmacological evaluation of a novel series of 3-aryl-2-(2-substituted-4-methylthiazole-5-yl)thiazolidin-4-one as possible anti-inflammatory and antimicrobial agents.  

Science.gov (United States)

A new series of 3-aryl-2-(2-aryl/benzyl-4-methylthiazole-5-yl)thiazolidin-4-one was synthesized by condensation of 2-aryl/benzyl-4-methylthiazole-5-carbaldehyde, aromatic amines and thioglycolic acid in toluene. All the synthesized compounds are characterized by IR, NMR and elemental or mass analysis. Sixteen out of the newly synthesized compounds were screened for in vivo anti-inflammatory activity using carrageenan-induced rat paw edema method. Some of the synthesized compounds exhibited good anti-inflammatory activity compared with indomethacin. The synthesized compounds were also evaluated for their in vitro antimicrobial activity. Some of the compounds showed mild antibacterial activity while most of the compounds showed good antifungal activity. PMID:22981329

Shelke, Shivaji H; Mhaske, Pravin C; Nandave, Mukesh; Narkhade, Sachin; Walhekar, Namdeo M; Bobade, Vivek D

2012-10-15

210

Arylation with unsymmetrical diaryliodonium salts: a chemoselectivity study.  

Science.gov (United States)

Phenols, anilines, and malonates have been arylated under metal-free conditions with twelve aryl(phenyl)iodonium salts in a systematic chemoselectivity study. A new "anti-ortho effect" has been identified in the arylation of malonates. Several "dummy groups" have been found that give complete chemoselectivity in the transfer of the phenyl moiety, irrespective of the nucleophile. An aryl exchange in the diaryliodonium salts has been observed under certain arylation conditions. DFT calculations have been performed to investigate the reaction mechanism and to elucidate the origins of the observed selectivities. These results are expected to facilitate the design of chiral diaryliodonium salts and the development of catalytic arylation reactions that are based on these sustainable and metal-free reagents. PMID:23788251

Malmgren, Joel; Santoro, Stefano; Jalalian, Nazli; Himo, Fahmi; Olofsson, Berit

2013-07-29

211

Pyrolysis studies of organic oxygenates 3. High temperature rearrangement of aryl alkyl ethers  

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Thermal chemistry pathways of aryl alkyl ethers have been investigated under coal conversion-like conditions. Anisole is a thermally reactive compound having an oxygen functionality found in such coal precursors as lignins. Pyrolysis of anisoles was carried out using small batch autoclaves. Under thermolysis conditions anisole yielded a product distribution strongly dependent upon experimental parameters. Phenol, methane, CO and benzaldehyde are the low molecular weight products and polyphenyls and polyethers are the predominant high molecular weight products. The generation of CO is explained by a high temperature rearrangement of the phenyl group from O- to C- followed by rapid thermal decarbonylation of the benzaldehyde. Carbon monoxide formation from aryl alkyl ether can thus be an important mechanistic pathway in coal conversion processes. By investigating the rearrangement using para-fluoroanisole it was shown that this rearrangement proceeds via a threecentered intermediate to para-fluorobenzaldehyde. No meta isomer was observed.

Schlosberg, R.H.; Ashe, T.R.; Danik, J.A.; Dupre, G.D.; Kurs, A.; Olmstead, W.N.; Szajowski, P.F.

1983-06-01

212

Synthesis of 2-aryl-5-styrylphospholes: promising candidates for the phosphole-based NLO chromophores.  

Science.gov (United States)

2-Aryl-1-phenyl-5-styrylphospholes were prepared in good yields in a one-pot procedure from the corresponding 1,9-diarylnona-8-ene-1,6-diynes and dichloro(phenyl)phosphine via intermediary titanacyclopentadienes. According to the UV-vis absorption and fluorescence spectra of this class of compounds, the optical properties of the phosphole-vinylene-bridged pi-conjugated system have been revealed to depend strongly on the electronic character of the terminal functionalities. In particular, the polarizability at the excited-state has been found to be considerably greater than that in the ground state. High molecular hyperpolarizabilities obtained for the push-pull type of 2-aryl-5-styrylphospholes in the hyper-Rayleigh scattering measurements demonstrate the potential utility of the stilbene-type phosphole derivatives as a new class of second-order NLO chromophores. PMID:17625887

Matano, Yoshihiro; Miyajima, Tooru; Imahori, Hiroshi; Kimura, Yoshifumi

2007-08-01

213

ONE-POT SYNTHESIS AND ANTITUBERCULAR ACTIVITY OF 2-AMINO-5-ARYL-5H-THIAZOLO [4,3-b]-1,3,4-THIADIAZOLES  

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Full Text Available A series of 2-amino-5-aryl-5H-thiazolo[4,3-b]-l,3,4-thiadiazoles were synthesized by using aromatic aldehydes, thioglycolic acid and thiosemicarbazide. Equimolar mixtures of aromatic aldehydes with thioglycolic acid and thiosemicarbazide in H2SO4 transform into 2-amino-5-aryl-5H-thiazolo[4,3-b]-l,3,4-thiadiazoles. Structures of all synthesized compounds were confirmed by FTIR, 1H NMR and mass spectral data. Their antitubercular activity has been studied. All the synthesized compounds have shown good antitubercular activity.

Karigar Asif A.

2011-01-01

214

Rhodium Catalyzed Direct Arylation of ?-Diazoimines.  

Science.gov (United States)

An efficient rhodium catalyzed direct arylation of ?-diazoimines, generated from readily accessible 1,2,3-triazole, has been accomplished for the synthesis of 2,2-diaryl enamides. The reaction involves the chemo- and regioselective insertion of rhodium azavinyl carbene into aromatic C(sp(2))-H bonds. Utility of the developed methodology was demonstrated in the synthesis of indole and tetrahydroisoquinoline frameworks. PMID:24724575

Yadagiri, Dongari; Anbarasan, Pazhamalai

2014-05-01

215

N-Heterocyclic carbenepalladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides  

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New PdNHC complexes have been synthesized and employed for palladium-catalyzed direct arylation of pyrrole derivatives by using electron-deficient aryl chlorides as coupling partners. The desired coupling products were obtained in moderate to good yields by using 1 mol % of these air-stable palladium complexes. This is an advantage compared to the procedures employing air-sensitive phosphines, which have been previously shown to promote the coupling of aryl chlorides with heteroarenes.

Ismail zdemir; Nevin Grbz; Nazan Kalo?lu; znur Do?an; Murat Kalo?lu; Christian Bruneau; Henri Doucet

2013-01-01

216

N-Heterocyclic carbenepalladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

New PdNHC complexes have been synthesized and employed for palladium-catalyzed direct arylation of pyrrole derivatives by using electron-deficient aryl chlorides as coupling partners. The desired coupling products were obtained in moderate to good yields by using 1 mol % of these air-stable palladium complexes. This is an advantage compared to the procedures employing air-sensitive phosphines, which have been previously shown to promote the coupling of aryl chlorides with heteroarenes.

O?zdemir, Ismail; Gu?rbu?z, Nevin; Kalog?lu, Nazan; Dog?an, O?znur; Kalog?lu, Murat; Bruneau, Christian; Doucet, Henri

2013-01-01

217

Design, synthesis and biological evaluation of aryl pyrimidine derivatives as potential leishmanicidal agents.  

Science.gov (United States)

A series of substituted aryl pyrimidine derivatives was synthesized and evaluated in vitro for their antileishmanial potential against intracellular amastigotes of Leishmania donovani using reporter gene luciferase assay. Among all, 8 compounds showed promising IC50 values ranging from 0.5 to 12.9 ?M. Selectivity indices (S.I.) of all these compounds are far better than reference drugs, sodium stibogluconate (SSG) and miltefosine. On the basis of good S.I., compounds were further screened for their in vivo antileishmanial activity against L. donovani/hamster model. Compounds 2d, 4a and 4b have shown significant inhibition of parasitic multiplication that is 88.4%, 78.1% and 78.2%, respectively at a daily dose of 50 mg/kg 5 days, when administered intraperitoneally. Compound 2d is most promising one, which may provide a new lead that could be exploited as a new antileishmanial agent. PMID:23910597

Suryawanshi, S N; Kumar, Santosh; Shivahare, Rahul; Pandey, Susmita; Tiwari, Avinash; Gupta, Suman

2013-09-15

218

Two new lactones and one new aryl-8-oxa-bicyclo[3,2,1]oct-3-en-2-one from Descurainia sophia.  

Science.gov (United States)

Two new lactones (1, 2), descurainolide A and B, and one new aryl-8-oxa-bicyclo[3,2,1]-oct-3-en-2-one (3), descurainin, together with five known compounds (4-8), were isolated from the seeds of Descurainia sophia (L.) WEBB ex PRANTL. The structures of the new compounds were elucidated by extensive studies of their 1D, 2D NMR and HR-MS. Compounds 4 and 5 showed cytotoxicity. PMID:15577251

Sun, Kai; Li, Xian; Li, Wen; Wang, Jinhui; Liu, Jianming; Sha, Yi

2004-12-01

219

Mechanism-based inactivation of benzo(a)pyrene hydroxylase by aryl acetylenes and aryl olefins  

Energy Technology Data Exchange (ETDEWEB)

A series of aryl acetylenes and aryl olefins have been examined as substrates and inhibitors of cytochrome P-450 dependent monooxgenases in liver microsomes from 5,6-benzoflavone or phenobarbital pretreated rats. 1-Ethynylpyrene, 3-ethynylperylene, 2-ethynylfluorene, methyl 1-pyrenyl acetylene, cis- and trans-1-(2-bromovinyl)pyrene, and 1-allylpyrene serve as mechanism-based irreversible inactivators (suicide inhibitors) of benzo(a)pyrene hydroxylase, while 1-vinylpyrene and phenyl 1-pyrenyl acetylene do not cause a detectable suicide inhibition of benzo(a)pyrene hydroxylase. The mechanism-based loss of benzo(a)pyrene hydroxylase caused by the aryl acetylenes is not accompanied by a corresponding loss of the P-450 content of the microsomes (suicide destruction). The suicide inhibition by these aryl acetylenes therefore does not involve covalent binding to the heme moiety of the monooxygenase. Nevertheless, in the presence of NADPH, /sup 3/H-labeled 1-ethynylpyrene becomes covalently attached to the cytochrome P-450 protein; the measured stoichiometry of binding is one 1-ethynylpyrene per P-450 heme unit. The authors conclude that the inhibition of benzo(a)pyrene hydroxylase produced by 1-ethynylpyrene may be related to the mechanism of suicide inhibition of P-450 activity by chloramphenicol rather than the mechanism of suicide destruction of P-450 previously described for acetylene and propyne.

Gan, L.S.; Lu, J.Y.L.; Alworth, W.L.

1986-05-01

220

Mechanism-based inactivation of benzo[a]pyrene hydroxylase by aryl acetylenes and aryl olefins  

International Nuclear Information System (INIS)

A series of aryl acetylenes and aryl olefins have been examined as substrates and inhibitors of cytochrome P-450 dependent monooxgenases in liver microsomes from 5,6-benzoflavone or phenobarbital pretreated rats. 1-Ethynylpyrene, 3-ethynylperylene, 2-ethynylfluorene, methyl 1-pyrenyl acetylene, cis- and trans-1-(2-bromovinyl)pyrene, and 1-allylpyrene serve as mechanism-based irreversible inactivators (suicide inhibitors) of benzo[a]pyrene hydroxylase, while 1-vinylpyrene and phenyl 1-pyrenyl acetylene do not cause a detectable suicide inhibition of benzo[a]pyrene hydroxylase. The mechanism-based loss of benzo[a]pyrene hydroxylase caused by the aryl acetylenes is not accompanied by a corresponding loss of the P-450 content of the microsomes (suicide destruction). The suicide inhibition by these aryl acetylenes therefore does not involve covalent binding to the heme moiety of the monooxygenase. Nevertheless, in the presence of NADPH, "3H-labeled 1-ethynylpyrene becomes covalently attached to the cytochrome P-450 protein; the measured stoichiometry of binding is one 1-ethynylpyrene per P-450 heme unit. The authors conclude that the inhibition of benzo[a]pyrene hydroxylase produced by 1-ethynylpyrene may be related to the mechanism of suicide inhibition of P-450 activity by chloramphenicol rather than the mechanism of suicide destruction of P-450 previously described for acetylene and propyne

1986-05-01

 
 
 
 
221

Iron catalyzed highly regioselective dimerization of terminal aryl alkynes.  

Science.gov (United States)

Iron can catalyze head-to-head dimerization of terminal aryl alkynes to give the corresponding (E) selective conjugated enynes in high yields. A variety of substituted aryl acetylenes underwent smooth dimerization using catalytic FeCl(3) and DMEDA in the presence of KO(t)Bu. PMID:21552588

Midya, Ganesh Chandra; Paladhi, Sushovan; Dhara, Kalyan; Dash, Jyotirmayee

2011-06-21

222

KI-catalyzed arylation of benzothiazoles from the coupling of aryl aldehydes with benzothiazoles in neat water.  

Science.gov (United States)

A KI-catalyzed oxidative coupling of benzothiazoles with aryl aldehydes has been developed using TBHP as an oxidant in neat water under metal free conditions. Various 2-aryl benzothiazoles were prepared in 36-79% yields for 28 examples. The mechanistic studies suggested that this transformation proceeded via a radical process. PMID:24407277

Gao, Yuyu; Song, Qiuling; Cheng, Guolin; Cui, Xiuling

2014-02-21

223

Direct C-H bond arylation of (benzo)oxazoles with aryl chlorides catalyzed by N-heterocyclic carbene-palladium(II)-1-methylimidazole complex.  

Science.gov (United States)

The direct C-H bond arylation of (benzo)oxazoles with aryl chlorides was achieved catalyzed by a well-defined NHC-Pd(II)-Im complex. Under the optimal conditions, various aryl chlorides were successfully applied as the arylating reagents to achieve the 2-aryl (benzo)oxazoles in acceptable to high yields, providing a convenient and alternative method for the direct C-H bond arylation of (benzo)oxazoles and enriching the chemistry of the NHC-Pd(II) complex in organic synthesis. PMID:24670076

Shen, Xiao-Bao; Zhang, Yun; Chen, Wen-Xin; Xiao, Zheng-Kang; Hu, Ting-Ting; Shao, Li-Xiong

2014-04-01

224

N-Heterocyclic Carbene-Palladium(II)-1-Methylimidazole Complex-Catalyzed Direct C-H Bond Arylation of (Benz)imidazoles with Aryl Chlorides.  

Science.gov (United States)

(Benz)imidazoles can be efficiently functionalized by (hetero)aryl chlorides via direct C-H bond arylation in the presence of a well-defined NHC-Pd(II)-Im complex. Under the optimal conditions, various activated, unactivated, and deactivated (hetero)aryl chlorides were successfully applied as the arylating reagents to achieve the 2-(hetero)aryl (benz)imidazoles in acceptable to high yields, giving a facile and alternative methodology for the direct C-H bond arylation of (benz)imidazoles. PMID:24869774

Gu, Zheng-Song; Chen, Wen-Xin; Shao, Li-Xiong

2014-06-20

225

Consecutive Three-Component Synthesis of 3-(HeteroAryl-1H-pyrazoles with Propynal Diethylacetal as a Three-Carbon Building Block  

Directory of Open Access Journals (Sweden)

Full Text Available A novel consecutive three-component synthesis of 3-(heteroaryl-1H-pyrazoles via room temperature Sonogashira arylation of propynal diethylacetal used as a propargyl aldehyde synthetic equivalent has been disclosed. The final acetal cleavage-cyclocondensation with hydrazine hydrochloride at 80 C rapidly furnishes the title compounds in a one-pot fashion.

Thomas J. J. Mller

2011-11-01

226

Discovery of 4-Substituted Methoxybenzoyl-Aryl-Thiazole as Novel Anticancer Agents: Synthesis, Biological Evaluation and Structure-Activity Relationships  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A series of 4-substituted methoxylbenzoyl-aryl-thiazoles (SMART) have been discovered and synthesized as a result of structural modifications of the lead compound 2-arylthiazolidine-4-carboxylic acid amides (ATCAA). The antiproliferative activity of the SMART agents against melanoma and prostate cancer cells was improved from ?M to low nM range compared with ATCAA series. The structure-activity relationship was discussed from modifications of A, B C rings and the linker. Pr...

2009-01-01

227

Bis-aryl Substituted Dioxaborines as Electron-Transport Materials: A Comparative Density Functional Theory Investigation with Oxadiazoles and Siloles  

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We report on a detailed quantum-chemical comparison of the electronic structures, vertical electron affinities, and intramolecular reorganization energies for bis-aryl substituted dioxaborine, oxadiazole, and silole derivatives. The results indicate that the HOMO and LUMO energies of the substituted compounds can be tuned on the order of 23 eV via minor changes in the substitution patterns, with the HOMO and LUMO levels for the dioxaborine derivatives consistently the most energy stabilize...

Risko, C.; Zojer, E.; Brocorens, Patrick; Marder, S. R.; Bre?das, Jean-luc

2005-01-01

228

Synthesis of a new N-substituted bis-benzimidazolyl diamide ligand and its trinuclear copper(II) complex: Structural and fluorescence studies  

Science.gov (United States)

The synthesis of a new N-substituted fluorescent probe based on a bis-benzimidazole diamide N2,N2'-bis[(1-(4-methylbenzyl)-benzimidazol-2-yl)methyl]biphenyl-2,2'-dicarboxamide (L1) with a biphenyl spacer group and its trinuclear copper(II) complex [Cu3(L1)3Cl3]?3Cl?3H2O] has been described. X-ray studies shows that the trinuclear complex crystallizes as [{Cu3(L1)3Cl3}2?6Cl?13CH3CN?2H2O] in triclinic space group P-1 with two independent molecules in the asymmetric unit. Each copper(II) adopts a distorted penta-coordinated geometry in each unit. The fluorescence spectra of L1 in methanol show an emission band centered at 300 nm. This band arises due to benzimidazolyl moiety in the ligating system. The diamide L1 in the presence of Fe3+ show the simultaneous 'quenching' of (300 nm) and 'enhancement' of (375 nm) emission band. The new emission band at 375 nm is attributed to intra ligand ?-?* transition of the biphenyl moiety. While Cu2+ and Ag+ show only the quenching of the 300 nm band. No such behavior was observed with other metal ions like Ni2+, Co2+, Mn2+, Mg2+, Zn2+ and Pb2+. The quenching constant with Fe3+, Ag+ and Cu2+ are calculated by the Stern-Volmer plots.

Mahiya, Kuldeep; Mathur, Pavan

2013-09-01

229

COMPUTER AIDED DESIGN AND MOLECULAR DOCKING STUDY OF 1-N-SUBSTITUTED-3, 5-DIPHENYL-2-PYRAZOLINE DERIVATIVES AS COX2 INHIBITORS  

Directory of Open Access Journals (Sweden)

Full Text Available Cyclooxygenase (COX catalyses the first committed step in the synthesis of prostanoids, a large family of arachidonic acid metabolites and major target of non-steroidal anti-inflammatory drugs (NSAIDs. COX-2 is the inducible isoform, rapidly expressed in several cell types in response to pro-inflammatory molecules. The interaction between the polypeptide and its corresponding receptor is highly selective. Therefore, it is of interest to inhibit COX2 in the context of inflammation. It is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process. The structure of COX 2 is screened using SP (Standard Precision method under molecular docking techniques (Computer aided Design with reference to novel 1-N-substituted-3, 5-diphenyl-2-pyrazoline derivatives. Based on their score and energy few ligands are selected to Induced Fit Docking (IFD studies and compared with the existing drug molecules. The result showed that the docked ligands maintain favorable interactions with the active site residues of COX-2. All docking studies were performed using the molecular modeling software GLIDE of Schrdinger package.

M Prasada Rao*, P Srinivasa Rao, Allam Appa Rao and Manda Rama Narasinga Rao

2013-10-01

230

Design and synthesis of some novel 4-(4-substituted aryl semicarbazones as anticonvulsant agents  

Directory of Open Access Journals (Sweden)

Full Text Available In the present study, a series of 4-(4-substituted aryl semicarbazones were synthesized from substituted anilines and subsequently evaluated for their anticonvulsant activities. The anticonvulsant activities were established by the anticonvulsant drug development (ADD programme NIH, USA using experimental animal, adult male FCM mice (20-25 g and adult Sprague-Dawley rats (100-150 g and screened against electroshock seizure, subcutaneous metrazole and minimal neurotoxicity tests in mice. Compound 7 was found equipotent to carbamazepine in both MES and ScPTZ tests. This study has highlighted the importance of distal alkyl chain which influences the anticonvulsant activity.

Singh Anita

2010-01-01

231

Design and Synthesis of Some Novel 4-(4-substituted aryl) Semicarbazones as Anticonvulsant Agents.  

Science.gov (United States)

In the present study, a series of 4-(4-substituted aryl) semicarbazones were synthesized from substituted anilines and subsequently evaluated for their anticonvulsant activities. The anticonvulsant activities were established by the anticonvulsant drug development (ADD) programme NIH, USA using experimental animal, adult male FCM mice (20-25 g) and adult Sprague-Dawley rats (100-150 g) and screened against electroshock seizure, subcutaneous metrazole and minimal neurotoxicity tests in mice. Compound 7 was found equipotent to carbamazepine in both MES and ScPTZ tests. This study has highlighted the importance of distal alkyl chain which influences the anticonvulsant activity. PMID:21188048

Singh, Anita; Pande, C; Gahtori, P; Pandeya, S N; Stables, J P

2010-05-01

232

Design and Synthesis of Some Novel 4-(4-substituted aryl) Semicarbazones as Anticonvulsant Agents  

Science.gov (United States)

In the present study, a series of 4-(4-substituted aryl) semicarbazones were synthesized from substituted anilines and subsequently evaluated for their anticonvulsant activities. The anticonvulsant activities were established by the anticonvulsant drug development (ADD) programme NIH, USA using experimental animal, adult male FCM mice (2025 g) and adult Sprague-Dawley rats (100150 g) and screened against electroshock seizure, subcutaneous metrazole and minimal neurotoxicity tests in mice. Compound 7 was found equipotent to carbamazepine in both MES and ScPTZ tests. This study has highlighted the importance of distal alkyl chain which influences the anticonvulsant activity.

Singh, Anita; Pande, C.; Gahtori, P.; Pandeya, S. N.; Stables, J. P.

2010-01-01

233

Anthocyan does not suppress transformation of aryl hydrocarbon receptor induced by dioxin.  

Science.gov (United States)

Dioxins cause a variety of toxic effects through transformation of a cytosolic aryl hydrocarbon receptor (AhR). We have previously demonstrated that certain natural flavones and flavonols at the dietary levels suppress AhR transformation. In this study, we investigated whether 5 anthocyanidins, 15 anthocyanins, and protocatechuic acid suppress AhR transformation in mouse hepatoma Hepa-1c1c7 cells. All the compounds tested here at 5 microM unexpectedly failed to suppress the transformation induced by 0.1 nM TCDD, indicating that anthocyan does not have a potential to prevent dioxin toxicity. PMID:15630228

Mukai, Rie; Fukuda, Itsuko; Nishiumi, Shin; Hosokawa, Keizo; Kanazawa, Kazuki; Ashida, Hitoshi

2004-01-01

234

New Synthesis and Antiparasitic Activity of Model 5-Aryl-1-methyl-4-nitroimidazoles  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A number of 5-aryl-1-methyl-4-nitroimidazoles 5a-f have been synthesized in good yields by the Suzuki coupling reaction between 5-chloro-1-methyl-4-nitroimidazole (3) and arylboronic acids 4a-f, aided by dichlorobis-(triphenylphosphine)palladium(II), K2CO3, and tetrabutylammonium bromide in water at 70-80 C. Compounds 5a-f were characterized by elemental analysis, NMR and MS spectral data. On the basis of in vitro screening data, 5-(3-chlorophenyl)-1-methyl-4-nitro-1H-imidazole (5f)exhibite...

Saadeh, Haythem A.; Mosleh, Ibrahim M.; El-abadelah, Mustafa M.

2009-01-01

235

Synthesis and anti-tuberculosis activity of N-aryl-C-nitroazoles.  

Science.gov (United States)

Twelve N-aryl derivatives of 4-nitroimidazole, 2-methyl-4-nitroimidazole, 4-nitropyrazole or 3-nitro-1,2,4-triazole have been synthesized either by a degenerated ring transformation reaction of 1,4-dinitroimidazoles with 4-substituted anilines or by a condensation of fluoronitrobenzenes with salts prepared from C-nitro-1H-azoles and 1,8-diazabicyclo[5.4.0]-7-undecene. The Tuberculosis Antimicrobial Acquisition and Coordinating Facility has provided anti-mycobacterial data concerning inhibition activity of 12 compounds. PMID:15464618

Walczak, Krzysztof; Gondela, Andrzej; Suwi?ski, Jerzy

2004-10-01

236

4-aryl piperazine and piperidine amides as novel mGluR5 positive allosteric modulators.  

Science.gov (United States)

Positive allosteric modulation of metabotropic glutamate receptor 5 (mGluR5) is regarded as a potential novel treatment for schizophrenic patients. Herein we report the synthesis and SAR of 4-aryl piperazine and piperidine amides as potent mGluR5 positive allosteric modulators (PAMs). Several analogs have excellent activity and desired drug-like properties. Compound 2b was further characterized as a PAM using several in vitro experiments, and produced robust activity in several preclinical animal models. PMID:21067920

Xiong, Hui; Brugel, Todd A; Balestra, Michael; Brown, Dean G; Brush, Kelly A; Hightower, Caprice; Hinkley, Lindsay; Hoesch, Valerie; Kang, James; Koether, Gerard M; McCauley, John P; McLaren, Francis M; Panko, Laura M; Simpson, Thomas R; Smith, Reed W; Woods, James M; Brockel, Becky; Chhajlani, Vijay; Gadient, Reto A; Spear, Nathan; Sygowski, Linda A; Zhang, Minli; Arora, Jalaj; Breysse, Nathalie; Wilson, Julie M; Isaac, Methvin; Slassi, Abdelmalik; King, Megan M

2010-12-15

237

Design and synthesis of imidazo[1,2-?][1,8]naphthyridine derivatives as anti-HCV agents via direct C-H arylation.  

Science.gov (United States)

RO8191 represents a newly identified small-molecule IFN-?-substitute, which displays potent anti-HCV activity. In this communication, we reported the design and synthesis of two series of imidazo[1,2-?][1,8]naphthyridine derivatives, as RO8191 analogues, via a direct C-H arylation approach. Notably, by adjusting the reaction conditions, we could achieve the two series of analogues via regioselective single- and double-arylations, respectively. The anti-HCV activities of the synthesized compounds were evaluated within the HCV cell culture system, and the preliminary results showed that some of them displayed promising anti-HCV activities. PMID:24595428

Huang, Shengdian; Qing, Jie; Wang, Shuo; Wang, Huan; Zhang, Linqi; Tang, Yefeng

2014-04-21

238

Synthesis, Characterization, Anti-Inflammatory and in Vitro Antimicrobial Activity of Some Novel Alkyl/Aryl Substituted Tertiary Alcohols  

Directory of Open Access Journals (Sweden)

Full Text Available The synthesis of some novel alkyl/aryl substituted tertiary alcohols was accomplished in two steps. The synthetic route involves preparation of Grignard reagents by treating alkyl/aryl bromides with magnesium turnings in dry ether. Then substituted chalcones were reacted with the Grignard reagents to afford alkyl/aryl substituted tertiary alcohols 1-10. The structures of the synthesized compounds were assigned on the basis of FT-IR, 1H-NMR, 13C-NMR and mass spectroscopic data. The in vivo anti-inflammatory activity of the synthesized compounds was evaluated using the carrageenan-induced hind paw edema method and was compared with that of ibuprofen. Some of the newly synthesized compounds showed promising anti-inflammatory activity. The tertiary alcohols 1-10 were also screened for antibacterial activity against ten bacterial strains using seven Gram-positive and three Gram-negative bacteria and for antifungal activity against Aspergillus Flavus, Aspergillus Niger and Aspergillus pterus. Tertiary alcohols 1-10 were found to exhibit good to excellent antimicrobial activities compared to levofloxacin and fluconazole used as standard drugs.

Rafiuzzaman SaeedulHaq

2011-12-01

239

Synthesis and pharmacological evaluation of (6-substituted 4-Oxo-4 H -chromene-3 yl) methyl N-substituted aminoacetates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A series of the title compounds were synthesized and characterized by spectral data. All the compounds were evaluated for in vitro antihistaminic activity by inhibition of isotonic contractions induced by histamine on isolated guinea pig ileum and the compound 6-k showed significant activity. A few compounds have also been screened for in vivo bronchodilatory activity. These compounds exhibited significant protection against histamine-induced convulsions in guinea pig at the...

Gajbhiye Asmita; Mallareddy V; Achaiah G

2008-01-01

240

Pharmacological and Structure-Activity Relationship Evaluation of 4-aryl-1-Diphenylacetyl(thiosemicarbazides  

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Full Text Available This article describes the synthesis of six 4-aryl-(thiosemicarbazides (series a and b linked with diphenylacetyl moiety along with their pharmacological evaluation on the central nervous system in mice and computational studies, including conformational analysis and electrostatic properties. All thiosemicarbazides (series b were found to exhibit strong antinociceptive activity in the behavioural model. Among them, compound 1-diphenylacetyl-4-(4-methylphenylthiosemicarbazide 1b was found to be the most potent analgesic agent, whose activity is connected with the opioid system. For compounds from series a significant anti-serotonergic effect, especially for compound 1-diphenylacetyl-4-(4-methoxyphenylsemicarbazide 2b was observed. The computational studies strongly support the obtained results.

Monika Wujec

2014-04-01

 
 
 
 
241

Synthesis Of [2h, 13c]M [2h2m 13c], And [2h3,, 13c] Methyl Aryl Sulfones And Sulfoxides  

Energy Technology Data Exchange (ETDEWEB)

The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfones and [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfoxides, wherein the .sup.13 C methyl group attached to the sulfur of the sulfone or sulfoxide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing methyl aryl sulfones and methyl aryl sulfoxides.

Martinez, Rodolfo A. (Santa Fe, NM); Alvarez, Marc A. (Santa Fe, NM); Silks, III, Louis A. (Los Alamos, NM); Unkefer, Clifford J. (Los Alamos, NM); Schmidt, Jurgen G. (Los Alamos, NM)

2004-07-20

242

Synthesis Of [2h, 13c] And [2h3, 13c]Methyl Aryl Sulfides  

Energy Technology Data Exchange (ETDEWEB)

The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2,.sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms. The present invention is also directed to the labeled compounds of [.sup.2 H.sub.1, .sup.13 C]methyl iodide and [.sup.2 H.sub.2, .sup.13 C]methyl iodide.

Martinez, Rodolfo A. (Santa Fe, NM); Alvarez, Marc A. (Santa Fe, NM); Silks, III, Louis A. (Los Alamos, NM); Unkefer, Clifford J. (Los Alamos, NM)

2004-03-30

243

Azo-hydrazone tautomerism of aryl azo pyridone dyes  

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Full Text Available In the last three or four decades disperse dyes derived from pyridones (in particular azo pyridone dyes have gained in importance, and are widely used in various fields. These compounds have excellent coloration properties, and are suitable for the dyeing of polyester fabrics. Basic features of these dyes are simplicity of their synthesis by diazotation and azo coupling. They generally have high molar extinction coefficient with medium to high light and wet fastness. The absorption maxima of these dyes show their visible absorption wavelength ranging from yellow to orange, which can be attributed to poorly delocalized electrons in the pyridone ring. However, there are several dyes with deep colors such as red or violet. Pyridone dyes with alkyl and aryl groups in ortho position to azo group show 2-pyridone/2-hydroxypyridine tautomerism, while those containing OH and NHR groups conjugated with the azo group show azo-hydrazone tautomerism. Determining azo-hydrazone tautomerism could be therefore interesting, since the tautomers have different physico-chemical properties and most importantly different coloration. The literature on azo-hydrazone tautomerism, determination of equilibrium position, and investigation of substituent and solvent influence on tautomerism has been summarized in the presented review. The general conclusion is that the equilibrium between two tautomers is influenced by the structure of the compounds and by the solvents used. The tautomeric behavior patterns of the arylazo pyridone dyes in the reviewed literature has been studied using various instrumental techniques, including FT-IR, UV-vis, and NMR spectroscopy. The quantum chemical calculations related to the azo-hydrazon tautomerism have also been included. A large number of pyridone dyes exist in hydrazone form in solid state, while in solvents there is a mixture of tautomers. In addition, the X-ray single-crystal diffraction data analysis of some commercial pyridone dyes has been discussed concluding that they all crystallize in the hydrazone form.

Mirkovi? Jelena M.

2013-01-01

244

Influence of terminal substitution on structural, DNA, protein binding, anticancer and antibacterial activities of palladium(II) complexes containing 3-methoxy salicylaldehyde-4(N) substituted thiosemicarbazones.  

Science.gov (United States)

The variable chelating behavior of 3-methoxysalicylaldehyde-4(N)-substituted thiosemicarbazones was observed in equimolar reactions with [PdCl(2)(PPh(3))(2)]. The new complexes were characterized by various analytical, spectroscopic techniques (mass, (1)H-NMR, absorption, IR). All the new complexes were structurally characterized by single crystal X-ray diffraction. Crystallographic results showed that the ligands H(2)L(1) and H(2)L(4) are coordinated as binegative tridentate ONS donor ligands in the complexes 1 and 4 by forming six and five member rings. However, the ligands H(2)L(2) and H(2)L(3) bound to palladium in 2 and 3 as uninegative bidentate NS donors by forming a five member chelate ring. From this study, it was found that the substitution on terminal 4(N)-nitrogen may have an influence on the chelating ability of thiosemicarbazone. The presence of hydrogen bonding in 2 and 3 might be responsible for preventing the coordination of phenolic oxygen to the metal ion. The interaction of the complexes with calf-thymus DNA (CT-DNA) has been explored by absorption and emission titration methods. Based on the observations, an electrostatic binding mode of DNA has been proposed. The protein binding studies were monitored by quenching of tryptophan and tyrosine residues in the presence of complexes using Lysozyme as model protein. Antibacterial activity studies of the complexes have been screened against pathogenic bacteria such as Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa. MIC50 values of the complexes showed that they exhibited significant activity against the pathogens and among them, 3 exhibited higher activity. Further, anticancer activity of the complexes on the lung cancer cell line A549 has also been studied. PMID:22222360

Kalaivani, P; Prabhakaran, R; Ramachandran, E; Dallemer, F; Paramaguru, G; Renganathan, R; Poornima, P; Vijaya Padma, V; Natarajan, K

2012-02-28

245

The Suggested Physiologic Aryl Hydrocarbon ReceptorActivator and Cytochrome P4501 Substrate6-Formylindolo[3,2-b]carbazole Is Present in Humans  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dioxins and other polycyclic aromatic compounds formedduring the combustion of waste and fossil fuels represent a riskto human health, as well as to the well being of our environment.Compounds of this nature exert carcinogenic and endocrinedisruptingeffects in experimental animals by binding to theorphan aryl hydrocarbon receptor (AhR). Understanding themechanism of action of these pollutants, as well as the physiologicalrole(s) of the AhR, requires identification of the endogenousligand(s) o...

Wincent, Emma; Amini, Nahid; Luecke, Sandra; Glatt, Hansruedi; Bergman, Jan; Crescenzi, Carlo; Rannug, Agneta; Rannug, Ulf

2009-01-01

246

Synthesis of radioiodinated aryl iodides via boronate precursors  

Energy Technology Data Exchange (ETDEWEB)

Arylboronate esters are converted to iodine-123 labeled aryl iodides using no-carrier-added iodine-123 labeled sodium iodide in the presence of chloramine-T. High yields of radiochemically pure products are obtained.

Kabalka, George W. E-mail: Kabalka@utk.edu; Akula, Murthy R.; Zhang Jianhua

2002-11-01

247

Synthesis of radioiodinated aryl iodides via boronate precursors  

International Nuclear Information System (INIS)

Arylboronate esters are converted to iodine-123 labeled aryl iodides using no-carrier-added iodine-123 labeled sodium iodide in the presence of chloramine-T. High yields of radiochemically pure products are obtained

2002-11-01

248

Regiocontrolled palladium-catalyzed arylative cyclizations of alkynols.  

Science.gov (United States)

Tuning the reactivity of arylpalladium intermediates enables control of catalytic arylative 5-exo and 6-endo cyclizations of alkynols. The two modes of cyclizations represent a rare example of controllable, regioselective difunctionalization of alkynes. The cyclizations are useful in offering a divergent synthesis of oxygen-containing heterocycles, which is of synthetic use for further derivatization. Formal synthesis of an hNK-1 receptor antagonist also showcases the utility of our arylative cyclization. PMID:24735330

Fujino, Daishi; Yorimitsu, Hideki; Osuka, Atsuhiro

2014-04-30

249

Direct arylation of polycyclic aromatic hydrocarbons through palladium catalysis.  

Science.gov (United States)

We have discovered that the combination of Pd(OAc)(2)/o-chloranil can catalyze the direct C-H bond arylation of polycyclic aromatic hydrocarbons (PAHs) with arylboroxins that occurs selectively at the K-region. The sequential integration of Pd-catalyzed direct arylation of PAHs and FeCl(3)-mediated cyclodehydrogenation is effective in rapidly extending a parent PAH ?-system with high directionality. PMID:21699210

Mochida, Kenji; Kawasumi, Katsuaki; Segawa, Yasutomo; Itami, Kenichiro

2011-07-20

250

Selective copper catalysed aromatic N-arylation in water  

DEFF Research Database (Denmark)

4,7-Dipyrrolidinyl-1,10-phenanthroline (DPPhen) was identified as an efficient ligand for copper catalyzed selective arom. N-arylation in water. N-Arylation of indoles, imidazoles and purines proceeds with moderate to excellent yields and complete selectivity over aliph. amines. Aq. medium and the possibility for low metal and ligand loadings give the process a benign environmental profile. [on SciFinder(R)

Engel-Andreasen, Jens; Shimpukade, Bharat

2013-01-01

251

A convenient catalyst system for microwave accelerated cross-coupling of a range of aryl boronic acids with aryl chlorides  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract A convenient microwave accelerated cross-coupling procedure between aryl chlorides with a range of boronic acids has been developed. An explanation for the low reactivity of highly fluorinated boronic acids in Suzuki coupling is provided.

Milton Edward J

2007-05-01

252

A convenient catalyst system for microwave accelerated cross-coupling of a range of aryl boronic acids with aryl chlorides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A convenient microwave accelerated cross-coupling procedure between aryl chlorides with a range of boronic acids has been developed. An explanation for the low reactivity of highly fluorinated boronic acids in Suzuki coupling is provided.

Clarke, Matthew L.; France, Marcia B.; Fuentes, Jose A.; Milton, Edward J.; Roff, Geoffrey J.

2007-01-01

253

A convenient catalyst system for microwave accelerated cross-coupling of a range of aryl boronic acids with aryl chlorides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract A convenient microwave accelerated cross-coupling procedure between aryl chlorides with a range of boronic acids has been developed. An explanation for the low reactivity of highly fluorinated boronic acids in Suzuki coupling is provided.

Clarke Matthew L; France Marcia B; Fuentes Jose A; Milton Edward J; Roff Geoffrey J

2007-01-01

254

Re-engineering aryl methylcarbamates to confer high selectivity for inhibition of Anopheles gambiae versus human acetylcholinesterase.  

Science.gov (United States)

To identify potential human-safe insecticides against the malaria mosquito we undertook an investigation of the structure-activity relationship of aryl methylcarbamates inhibitors of acetylcholinesterase (AChE). Compounds bearing a ?-branched 2-alkoxy or 2-thioalkyl group were found to possess good selectivity for inhibition of Anopheles gambiae AChE over human AChE; up to 530-fold selectivity was achieved with carbamate 11d. A 3D QSAR model is presented that is reasonably consistent with log inhibition selectivity of 34 carbamates. Toxicity of these compounds to live Anopheles gambiae was demonstrated using both tarsal contact (filter paper) and topical application protocols. PMID:22738634

Hartsel, Joshua A; Wong, Dawn M; Mutunga, James M; Ma, Ming; Anderson, Troy D; Wysinski, Ania; Islam, Rafique; Wong, Eric A; Paulson, Sally L; Li, Jianyong; Lam, Polo C H; Totrov, Maxim M; Bloomquist, Jeffrey R; Carlier, Paul R

2012-07-15

255

Selective antagonists at group I metabotropic glutamate receptors: synthesis and molecular pharmacology of 4-aryl-3-isoxazolol amino acids  

DEFF Research Database (Denmark)

Homologation of (S)-glutamic acid (Glu, 1) and Glu analogues has previously provided ligands with activity at metabotropic Glu receptors (mGluRs). The homologue of ibotenic acid (7), 2-amino-3-(3-hydroxy-5-isoxazolyl)propionic acid (HIBO, 8), and the 4-phenyl derivative of 8, compound 9a, are both antagonists at group I mGluRs. Here we report the synthesis and molecular pharmacology of HIBO analogues 9b-h containing different 4-aryl substituents. All of these compounds possess antagonist activity at group I mGluRs but are inactive at group II and III mGluRs.

Kromann, Hasse; Sløk, Frank A

2002-01-01

256

Tetrakis(triethyl phosphite)(nickel(O): catalyst for the reactions of aryl halides with trialkyl phosphites  

Energy Technology Data Exchange (ETDEWEB)

The authors report the discovery of a new catalyst for the reactions of aryl halides with trialkyl phosphites, namely, tetrakis(triethyl phosphite)Ni(O). They suppose that catalysis by the Ni(O) complex consists of two stages. The first is the oxidative addition of the aryl halide to the Ni(O) complex. The second is reductive elimination with the regeneration of the catalyst. The proposed scheme is confirmed by the results of the methods of molecular spectroscopy. The formation of a tetrahedral paramagnetic complex is characterized by a weakening and broadening of the /sup 31/P signal and by a downfield shift of the compounds by 20-60 ppm.

Krasil-nikova, E.A.; Berdnik, I.V.; Sentemov, V.V.; Shagvaleev, F.S.; Zykova, T.V.

1986-10-10

257

Extended application of a chiral stationary phase based on (+)-(1 8-crown-6)-2,3,11,12-tetracarboxylic acid to the resolution of N-(substituted benzoyl)-alpha-amino acid amides.  

Science.gov (United States)

A chiral stationary phase (CSP 1) based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid was applied to the resolution of N-(substituted benzoyl)-alpha-amino acid amides and esters. N-(Substituted benzoyl)-alpha-amino acid amides were well resolved using a mixture of acetic acid-triethylamine-acetonitrile (0.01:0.05:100, v/v/v) as an optimum mobile phase while N-(substituted benzoyl)-alpha-amino acid esters were not resolved at all. In contrast, both N-(substituted benzoyl)-alpha-amino acid amides and esters were not resolved at all or resolved very poorly on another CSP (CSP 2), which lacks the two N-H hydrogens of the amide tethers of CSP 1. Among the substituents on the benzoyl group of analytes, the nitro group was the best for good resolution of analytes on CSP 1. From these results, the two N-H hydrogens of the amide tethers of CSP 1, the carbonyl oxygen of the amide group of analytes, and the nitro group on the benzoyl group of analytes were concluded to play significant roles in chiral recognition. In addition, various N-(3,5-dinitrobenzoyl)leucine amides with different lengths of N-alkylamide chains were resolved on CSP 1 and N-(3,5-dinitrobenzoyl) leucine N-propylamide was found to show the best chiral recognition in terms of the separation (alpha = 1.30) and the resolution factor (Rs= 3.17). PMID:16894785

Tan, Guanghui; Xue, Jin Ying; Hyun, Myung Ho

2006-07-01

258

Design, synthesis and diuretic activity of some novel 2,4-diamino-6-aryl-7-arylaminopyrimido [4,5-d]pyrimidin-5(6H)-ones.  

Science.gov (United States)

Synthesis and diuretic activity of some novel 2,4-diamino-6-aryl-7-arylaminopyrimidol4,5-d]pyrimidin-5(6H) -ones were described. The series was designed on the basis of structural similarity between pteridines and pyridopyrimidines. Designed molecules were synthesized by cyclo-condensation of 5-cyano-6-methylmercapto-3-aryl-2-arylaminopyrimidin-4(3H)-one with guanidine. All the compounds were screened for their diuretic activity using triamterene and furosemide as standard drugs. Compounds 2a, 2b, 2d, 2e and 2f were found more potent than triamterene. Compound 2e exhibited diuretic activity comparable to furosemide with greater natriuretic effect. It also exhibited significant antihypertensive activity. PMID:16889118

Rathod, Ishwarsinh S; Chhabria, Mahesh T; Chaudhari, Atul S; Jani, Mitesh H

2006-01-01

259

The use of AgNO3/BF3.Et2O and HNO3/Al(H2PO43 systems in the synthesis of aryl thiosulfonates  

Directory of Open Access Journals (Sweden)

Full Text Available The thiosulfonates are a class of compounds of great industrial importance. It is worth noting that the aryl thiosulfonates present several biological activities. The synthesis of these compounds is known in the literature although; only a few make use of thiols as the sole starting material. This work shows the use of two reaction systems employed for the synthesis of nitrophenols, AgNO3/BF3.EtO2 (I and HNO3/Al(H2PO43 (II, as an alternative to the preparation of aryl thiosulfonates. The use of system I led to higher yields (72-76% then system II (56-61%. These methodologies have not been reported before for the synthesis of these compounds and the products were obtained with good purity.

Edson Anjos Santos

2012-06-01

260

Synthesis and bio-evaluation of aryl hydrazono esters for oviposition responses in Aedes albopictus.  

Science.gov (United States)

A novel series of aryl hydrazono esters (AHE) (1-13) were synthesized (yield 76-98%) to study the oviposition responses in Aedes albopictus (Skuse) mosquitoes for the first time. At a concentration of 10?gml(-1) in dual choice experiment, among the screened compounds, AHE-12 showed remarkable oviposition attractant activity with an oviposition activity index (OAI) of +0.299 (greater than 95% confidence limit) comparable to p-cresol (OAI +0.320) which is well-reported oviposition attractant for Aedes aegypti. Conversely, AHE-10 exhibited highest oviposition deterrent activity with OAI -0.247. The possible utilization of these compounds will be in integrated vector management strategies. PMID:21193312

Bandyopadhyay, Prabal; Guha, Lopamudra; Seenivasagan, T; Sathe, Manisha; Sharma, Pratibha; Parashar, B D; Kaushik, M P

2011-01-15

 
 
 
 
261

Aryl chain analogues of the biotin vitamers as potential herbicides. Part 3.  

Science.gov (United States)

Novel aryl chain isosters and analogues of 7-keto-8-aminopelargonic acid (KAPA) and 7,8-diaminopelargonic acid (DAPA), the vitamer intermediates involved in the biosynthetic pathway of biotin, possessing chain lengths of eight carbon atoms, were prepared and evaluated as potential herbicides. In the greenhouse test the most active compounds were the fluorinated derivative 9d and the selenophenyl/furan mixture 17m/17p, which were most active against Foxtail millet. In the more sensitive Arabidopsis test the most active substances were 9a and 17m, which displayed GR(50) (concentration of active compound causing 50% growth inhibition) values of 0.2 and 0.5 mg kg(-1) respectively (values of < 50 mg kg(-1) are considered herbicidal). PMID:17665367

Ashkenazi, Tali; Pinkert, Dalia; Nudelman, Ayelet; Widberg, Ayala; Wexler, Barry; Wittenbach, Vernon; Flint, Dennis; Nudelman, Abraham

2007-10-01

262

Inhibition of Mycobacterium tuberculosis transaminase BioA by aryl hydrazines and hydrazides.  

Science.gov (United States)

7,8-Diaminopelargonic acid synthase (BioA) of Mycobacterium tuberculosis is a recently validated target for therapeutic intervention in the treatment of tuberculosis (TB). Using biophysical fragment screening and structural characterization of compounds, we have identified a potent aryl hydrazine inhibitor of BioA that reversibly modifies the pyridoxal-5'-phosphate (PLP) cofactor, forming a stable quinonoid. Analogous hydrazides also form covalent adducts that can be observed crystallographically but are incapable of inactivating the enzyme. In the X-ray crystal structures, small molecules induce unexpected conformational remodeling in the substrate binding site. We compared these conformational changes to those induced upon binding of the substrate (7-keto-8-aminopelargonic acid), and characterized the inhibition kinetics and the X-ray crystal structures of BioA with the hydrazine compound and analogues to unveil the mechanism of this reversible covalent modification. PMID:24482078

Dai, Ran; Wilson, Daniel J; Geders, Todd W; Aldrich, Courtney C; Finzel, Barry C

2014-03-01

263

6-Aryl and heterocycle quinazoline derivatives as potent EGFR inhibitors with improved activity toward gefitinib-sensitive and -resistant tumor cell lines.  

Science.gov (United States)

A group of novel anilinoquinazoline derivatives with variable aryl and heterocyclic substituents at position?6 were synthesized and tested for their EGFR-inhibitory activity. Aryl and heterocyclic rings were attached to the quinazoline scaffold through different linkages such as imine, amide, and thiourea. Most of the aryl and heterocyclic derivatives showed potent inhibition of wild-type EGFR with IC?? values in the low nanomolar range. Among these, thiourea derivatives 6?a, 6?b and compound 10?b also retained significant activity toward the gefitinib-insensitive EGFR(T790M/L858R) mutant, displaying up to 24-fold greater potency than gefitinib. In addition, cell growth inhibitory activity was tested against cancer cell lines with wild-type (KB cells) and mutant EGFR (H1975 cells). Several compounds including 6?a were found to be more potent than the reference compound gefitinib toward both cell lines, as was the case for compound 10?b against H1975 cells. Therefore, compounds 6?a and 10?b in particular may serve as new leads for the development of inhibitors effective against wild-type EGFR as well as gefitinib-resistant mutants. PMID:23847159

Hamed, Mostafa M; Abou El Ella, Dalal A; Keeton, Adam B; Piazza, Gary A; Abadi, Ashraf H; Hartmann, Rolf W; Engel, Matthias

2013-09-01

264

4-Aryl-4H-naphthopyrans derivatives: one-pot synthesis, evaluation of Src kinase inhibitory and anti-proliferative activities  

Science.gov (United States)

Background A series of 2-amino-4-aryl-4H-benzo[h or f]chromene-3-carbonitrile derivatives were synthesized and evaluated for inhibition of Src kinase and cell proliferation in breast carcinoma (BT-20) cell lines. Methods The one-pot, three-component reaction of ? or ?-naphthol, malonitrile and an aromatic aldehyde in the presence of diammonium hydrogen phosphate was afforded the corresponding 2-amino-4-aryl-4H-benzo[h or f]chromene-3-carbonitrile derivatives, All target compounds were evaluated for inhibition of Src kinase and cell proliferation in breast carcinoma (BT-20) cell lines. Results Among all tested compounds, unsubstituted 4-phenyl analog 4a showed Src kinas inhibitory effect with IC50 value of 28.1 ?M and was the most potent compound in this series. In general, the compounds were moderately active against BT-20. 3-Nitro-phenyl 4e and 3-pyridinyl 4h derivatives inhibited the cell proliferation of BT-20 cells by 33% and 31.5%, respectively, and found to be more potent compared to doxorubicin (25% inhibition of cell growth). Conclusion The data indicate that 4-aryl-4H-naphthopyrans scaffold has the potential to be optimized further for designing more potent Src kinase inhibitors and/or anticancer lead compounds.

2012-01-01

265

Novel N-Substituted Benzimidazolones as Potent, Selective, CNS-Penetrant, and Orally Active M1 mAChR Agonists.  

Science.gov (United States)

Virtual screening of the corporate compound collection yielded compound 1 as a subtype selective muscarinic M1 receptor agonist hit. Initial optimization of the N-capping group of the central piperidine ring resulted in compounds 2 and 3 with significantly improved potency and selectivity. Subsequent optimization of substituents on the phenyl ring of the benzimidazolone moiety led to the discovery of novel muscarinic M1 receptor agonists 4 and 5 with excellent potency, general and subtype selectivity, and pharmacokinetic (PK) properties including good central nervous system (CNS) penetration and oral bioavailability. Compound 5 showed robust in vivo activities in animal models of cognition enhancement. The combination of high potency, excellent selectivity, and good PK properties makes compounds 4 and 5 valuable tool compounds for investigating and validating potential therapeutic benefits resulting from selective M1 activation. PMID:24900202

Budzik, Brian; Garzya, Vincenzo; Shi, Dongchuan; Walker, Graham; Woolley-Roberts, Marie; Pardoe, Joanne; Lucas, Adam; Tehan, Ben; Rivero, Ralph A; Langmead, Christopher J; Watson, Jeannette; Wu, Zining; Forbes, Ian T; Jin, Jian

2010-09-01

266

Carbon-Hydrogen Bond Functionalization Approach for the Synthesis of Fluorenones and ortho-Arylated Benzonitriles  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A palladium-catalyzed benzamide ortho-arylation/reaction with (CF3CO)2O sequence was developed allowing a convenient one-pot synthesis of ortho-arylated benzonitriles and fluorenone derivatives. The outcome of this transformation is dependent on the amide N-alkyl substituent. Dehydration of ortho-arylated N-cyclohexyl-benzamides by (CF3CO)2O results in efficient production of benzonitriles. In contrast, o-arylated N-propylbenzamides are converted to fluorenone derivatives.

Shabashov, Dmitry; Molina Maldonado, Jesu?s R.; Daugulis, Olafs

2008-01-01

267

Aryliodine (III) Diacetates as Substrates for Pd-Ag Catalyzed Arylation of Alkenes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An unprecedented application of aryliodine (III) diacetates as substrates in Pd-Ag catalyzed arylation of alkenes is described. The mechanistic studies revealed that the binary Pd-Ag catalysis leads to the decomposition of aryliodine (III) diacetates to oxygen and aryl iodides followed by arylation of alkenes forming Heck-type products. Under optimized conditions both electron-rich and electron-deficient alkenes undergo arylation in high yields. Advantageously, the reaction proceeds smoothly ...

Evdokimov, Nikolai M.; Kornienko, Alexander; Magedov, Igor V.

2011-01-01

268

Cytotoxic 5-aryl-1-(4-nitrophenyl)-3-oxo-1,4-pentadienes mounted on alicyclic scaffolds.  

Science.gov (United States)

The 5-aryl-1-(4-nitrophenyl)-3-oxo-1,4-pentadienyl pharmacophore was incorporated into four series of compounds 1-4. Compounds 1a-g comprised a cluster of 3-arylidene-1-(4-nitrophenylmethylene)-2-oxo-3,4-dihydro-1H-naphthalenes while the analogues 2a-g consisted of a group of 6-arylidene-2-(4-nitrophenylmethylene)cyclohexanones. Three other compounds prepared in this study were 1-(4-nitrophenylmethylene)-3-(3,4,5-trimethoxyphenylmethylene)-2-oxo-2,3-dihydro-1H-indene 3a as well as two 5-arylidene-2-(4-nitrophenylmethylene)cyclopentanones 4a,b. The compounds were evaluated against human Molt 4/C8 and CEM T-lymphocytes as well as murine L1210 cells. In general, the compounds in series 1 displayed marked cytotoxicity having IC50 values in the 1-5 microM range while the related cyclohexyl analogues in series 2 were slightly less potent (IC50 figures were mainly 5-10 microM). The relative locations of two aryl rings present in all four series were considered to contribute significantly to bioactivity and may have accounted for the virtual absence of cytotoxic properties in series 3 and 4. Most of the compounds were administered intraperitoneally to mice using doses up to and including 300 mg/kg. No mortalities were noted. The inhibiting effect of most of the compounds towards Helicobacter pylori is noteworthy. The modes of action of representative compounds include the induction of apoptosis while some compounds weakly inhibited tubulin polymerisation and human N-myristoyltransferase. PMID:16581158

Das, Umashankar; Gul, H Inci; Alcorn, Jane; Shrivastav, Anuraag; George, Theresa; Sharma, Rajendra K; Nienaber, Kurt H; De Clercq, Erik; Balzarini, Jan; Kawase, Masami; Kan, Noriyuki; Tanaka, Toru; Tani, Satoru; Werbovetz, Karl A; Yakovich, Adam J; Manavathu, Elias K; Stables, James P; Dimmock, Jonathan R

2006-05-01

269

Carbonates: Eco-friendly Solvents for Palladium-Catalysed Direct Arylation of Heteroaromatics  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The palladium-catalysed direct 2-, 4- or 5-arylation of a wide range of heteroaromatics with aryl halides proceed in moderate to good yields using the eco-friendly solvents carbonates. The best yields were obtained using benzoxazole or thiazole derivatives. The arylation of furan, thiophene, pyrrole, imidazole or isoxazole derivatives was found to require a more elevated reaction temperature.

Dong, Jia Jia; Roger, Julien; Verrier, Ce?cile; Martin, Thibaut; Le Goff, Ronan; Hoarau, Christophe; Doucet, Henri

2010-01-01

270

Lifetime time measurements, Kamlet-Taft and Catalan solvatochromism of some 2-aryl benzimidazole derivatives  

Science.gov (United States)

Some 2-aryl benzimidazole derivatives (1-6) have been prepared and characterized by different spectral techniques. Fluorescence lifetime of synthesized 2-aryl benzimidazole derivatives was calculated. Kamlet-Taft and Catalan solvatochromism of synthesized 2-aryl benzimidazole derivatives have been discussed. Crystal structure of 1-(4-methylbenzyl)-2-p-tolyl-1H-benzo[d]imidazole has been studied.

Jayabharathi, J.; Jayamoorthy, K.; Thanikachalam, V.

2013-01-01

271

Palladium-Catalyzed Conversion of Aryl and Vinyl Triflates to Bromides and Chlorides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A facile Pd-catalyzed conversion of aryl and vinyl triflates to aryl and vinyl halides (bromides and chlorides) is described. This method allows convenient access to a variety of aryl, heteroaryl, and vinyl halides in good to excellent yields and with greatly simplified conditions relative to our previous report.

Pan, Jun; Wang, Xinyan; Zhang, Yong; Buchwald, Stephen Leffler

2011-01-01

272

An Efficient System For the Pd-Catalyzed Cross-Coupling of Amides and Aryl Chlorides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A catalyst based on a new biarylphosphine ligand (3) for the Pd-catalyzed cross-coupling reactions of amides and aryl chlorides is described. This system shows the highest turnover frequencies reported to date for these reactions, especially for aryl chloride substrates bearing an ortho substituent. An array of amides and aryl chlorides were successfully reacted in good to excellent yields.

Fors, Brett P.; Dooleweerdt, Karin; Zeng, Qingle; Buchwald, Stephen L.

2009-01-01

273

Palladium-Catalyzed Conversion of Aryl and Vinyl Triflates to Bromides and Chlorides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The palladium-catalyzed conversion of aryl and vinyl triflates to aryl and vinyl halides (bromides and chlorides) has been developed using dialkylbiaryl phosphine ligands. A variety of aryl, heteroaryl, and vinyl halides can be prepared via this method in good to excellent yields.

Shen, Xiaoqiang; Hyde, Alan M.; Buchwald, Stephen Leffler

2010-01-01

274

Palladium-Catalyzed Conversion of Aryl and Vinyl Triflates to Bromides and Chlorides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The palladium-catalyzed conversion of aryl and vinyl triflates to aryl and vinyl halides (bromides and chlorides) has been developed using dialkylbiaryl phosphine ligands. A variety of aryl, heteroaryl and vinyl halides can be prepared via this method in good to excellent yields.

Shen, Xiaoqiang; Hyde, Alan M.; Buchwald, Stephen L.

2010-01-01

275

Borylation of Unactivated Aryl Chlorides under Mild Conditions by Using Diisopropylaminoborane as a Borylating Reagent.  

Science.gov (United States)

The synthesis of arylboronic ester derivatives from aryl chlorides by using aryl(amino)boranes is described. Palladium-catalyzed coupling between aryl chlorides and diisopropylaminoborane leads to the formation of a C?B bond under mild conditions. A wide range of functional groups are tolerated, making this method particularly useful for the borylation of functionalized aromatics. PMID:24729439

Guerrand, Hlne D S; Marciasini, Ludovic D; Jousseaume, Mlissa; Vaultier, Michel; Pucheault, Mathieu

2014-05-01

276

Rhodium(III)-catalyzed redox-neutral C-H arylation via rearomatization.  

Science.gov (United States)

Rhodium(III)-catalyzed arylation of arenes bearing a chelating group has been realized via a redox-economy process using 4-hydroxycyclohexa-2,5-dienones as the arylating reagents, leading to the synthesis of 3-arylated phenols. This redox-neutral process proceeds via a C-H activation pathway with rearomatization being the driving force. PMID:24588394

Zhang, Xueyun; Wang, Fen; Qi, Zisong; Yu, Songjie; Li, Xingwei

2014-03-21

277

Microbiome-derived tryptophan metabolites and their aryl hydrocarbon receptor-dependent agonist and antagonist activities.  

Science.gov (United States)

The tryptophan metabolites indole, indole-3-acetate, and tryptamine were identified in mouse cecal extracts and fecal pellets by mass spectrometry. The aryl hydrocarbon receptor (AHR) agonist and antagonist activities of these microbiota-derived compounds were investigated in CaCo-2 intestinal cells as a model for understanding their interactions with colonic tissue, which is highly aryl hydrocarbon (Ah)-responsive. Activation of Ah-responsive genes demonstrated that tryptamine and indole 3-acetate were AHR agonists, whereas indole was an AHR antagonist that inhibited TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin)-induced CYP1A1 expression. In contrast, the tryptophan metabolites exhibited minimal anti-inflammatory activities, whereas TCDD decreased phorbol ester-induced CXCR4 [chemokine (C-X-C motif) receptor 4] gene expression, and this response was AHR dependent. These results demonstrate that the tryptophan metabolites indole, tryptamine, and indole-3-acetate modulate AHR-mediated responses in CaCo-2 cells, and concentrations of indole that exhibit AHR antagonist activity (100-250 ?M) are detected in the intestinal microbiome. PMID:24563545

Jin, Un-Ho; Lee, Syng-Ook; Sridharan, Gautham; Lee, Kyongbum; Davidson, Laurie A; Jayaraman, Arul; Chapkin, Robert S; Alaniz, Robert; Safe, Stephen

2014-05-01

278

Enhancing the cellular uptake of Py-Im polyamides through next-generation aryl turns.  

Science.gov (United States)

Pyrrole-imidazole (Py-Im) hairpin polyamides are a class of programmable, sequence-specific DNA binding oligomers capable of disrupting protein-DNA interactions and modulating gene expression in living cells. Methods to control the cellular uptake and nuclear localization of these compounds are essential to their application as molecular probes or therapeutic agents. Here, we explore modifications of the hairpin ?-aminobutyric acid turn unit as a means to enhance cellular uptake and biological activity. Remarkably, introduction of a simple aryl group at the turn potentiates the biological effects of a polyamide targeting the sequence 5'-WGWWCW-3' (W =A/T) by up to two orders of magnitude. Confocal microscopy and quantitative flow cytometry analysis suggest this enhanced potency is due to increased nuclear uptake. Finally, we explore the generality of this approach and find that aryl-turn modifications enhance the uptake of all polyamides tested, while having a variable effect on the upper limit of polyamide nuclear accumulation. Overall this provides a step forward for controlling the intracellular concentration of Py-Im polyamides that will prove valuable for future applications in which biological potency is essential. PMID:22080545

Meier, Jordan L; Montgomery, David C; Dervan, Peter B

2012-03-01

279

Synthesis of 2-aryl-3,4-dihydroisoquinolin-2-ium bromides and their in vitro acaricidal activity against Psoroptes cuniculi.  

Science.gov (United States)

By employing sanguinarine, a natural active quaternary isoquinoline alkaloid, as a model molecule, a series of structurally simple quaternary 2-aryl-3,4-dihydroisoquinolin-2-ium compounds were designed and synthesized and evaluated for in vitro acaricidal activity against P. cuniculi. A new approach towards the title compounds was developed with isochroman as starting material. The results showed that 22 of 24 tested compounds displayed the activity in varying degrees at 0.4 mg/mL. Fourteen compounds were significantly more effective than ivermectin, a standard acaricide, and 6-methoxy dihydrosanguinarine, a derivative of sanguinarine (p<0.05). And their comprehensive relative activity was 1.4 to 16.5 times than that of ivermectin and 1.5 to 18.8 times than that of 6-methoxy dihydrosanguinarine. The structure-activity relationship indicated that the introduction of a substituent to N-benzene ring, especially halogen atom and trifluoromethyl group, led to great improvement of the activity. The position of fluorine atom, methyl group and hydroxyl group made very significant effects on the activity. It was concluded that 2-aryl-3,4-dihydroisoquinolin-2-iums are very promising candidates for the development of new isoquinoline acaricidal agents. PMID:23221611

Ma, Yan-Ni; Yang, Xin-Juan; Pan, Le; Hou, Zhe; Geng, Hui-Ling; Song, Xiao-Ping; Zhou, Le; Miao, Fang

2013-01-01

280

Synthesis and antifungal activity of some new 3-hydroxy-2-(1-phenyl-3-aryl-4-pyrazolyl) chromones.  

Science.gov (United States)

Seven new 3-hydroxy-2-(1-phenyl-3-aryl-4-pyrazolyl) chromones 4a-g have been synthesized by the oxidation of 2-hydroxychalcone analogues of pyrazole 3a-g with hydrogen peroxide (H(2)O(2)) in KOH-MeOH by Algar Flynn Oymanda (AFO) reaction. The structures of the compounds 4 were established by the combined use of (1)H NMR, IR and mass spectra. All the seven compounds were tested in vitro for their antifungal activity against three phytopathogenic fungi, namely Helminthosporium species, Fusarium oxysporum and Alternaria alternata. Five compounds 4a, 4b, 4c, 4e and 4f were associated with substantially higher antifungal activity than commercial antifungal compound Actidione (cycloheximide) against all three phytopathogenic fungi. PMID:17555846

Prakash, Om; Kumar, Rajesh; Parkash, Vipin

2008-02-01

 
 
 
 
281

Synthesis and biological evaluation of a novel series of aryl S,N-ketene acetals as antileishmanial agents.  

Science.gov (United States)

A series of aryl S,N-ketene acetals 7(a-f) was synthesized and evaluated for their in vitro and in vivo antileishmanial activity against Leishmania donovani. All the 6 compounds exhibited significant in vitro activity against intracellular amastigotes of L. donovani with IC50 values ranging from 1.2 to 3.5 ?M and were found promising as compared with reference drugs, sodium stibogluconate (SSG) and paromomycin. On the basis of good selectivity indices (SI), they were further tested for their in vivo potential against L. donovani/hamster model. Two compounds 7a and 7b showed significant inhibition of parasite multiplication, 72% and 83%, respectively. These compounds were comparable with SSG and superior to paromomycin. Preliminary in vitro metabolic investigations were also performed to assess the metabolic stability and in vitro hepatic intrinsic clearance (Clint) of compound 7b in hamster liver microsomes. PMID:23673014

Suryawanshi, S N; Kumar, Santosh; Tiwari, Avinash; Shivahare, Rahul; Chhonker, Yashpal Singh; Pandey, Susmita; Shakya, Nishi; Bhatta, Rabi Sankar; Gupta, Suman

2013-07-01

282

Fragmentation of protonated O,O-dimethyl O-aryl phosphorothionates in tandem mass spectral analysis.  

Science.gov (United States)

A study was carried out on the fragmentation of 12 protonated O,O-dimethyl O-aryl phosphorothionates by tandem quadrupole mass spectrometry. Some of the studied compounds are used in agriculture as pesticides. Energy-resolved and pressure-resolved experiments were performed on the [M + H](+) ions to investigate the dissociation behavior of the ions with various amounts of internal energy. On collisionally activated dissociation, the [M + H](+) ions decompose to yield the [M + H - CH3OH](+), (CH3O)2PS(+) (m/z 125), and (CH3O)2PO(+) (m/z 109) ions as major fragments. The ions [M + H - CH3OH](+) and (CH3O)2PS(+) probably arise from the [M + H](+) ions of the O,O-dimethyl O-aryl phosphorothionates with the proton on the sulfur or on the oxygen of the phenoxy group. The origin of the hydroxy proton of the methanol fragment was in many cases, surprisingly, the phenyl group and not the reagent gas. This was confirmed by using deuterated isobutane, C4D10, as reagent gas in Cl. The fragment ions (CH3O)2PO(+) and [ZPhS](+) are the results of thiono-thiolo rearrangement reaction. The precursor ion for the ion (CH3O)2PO(+) arises from most compounds upon chemical ionization, whereas the precursor ion for the ion [ZPhS](+) arises only from a few compounds upon chemical ionization. The observed fragments imply that several sites carry the extra proton and that these sites get the proton usually upon ionization. The stability order and some characteristics of three protomers of O,O-dimethyl O-phenyl phosphorothionate were investigated by ab initio calculations at the RHF/3-21G* level of theory. PMID:24214301

Kuivalainen, T; Kostiainen, R; Bjrk, H; Uggla, R; Sundberg, M R

1995-06-01

283

Heck Reactions with Aryl Chlorides : Studies of Regio- and Stereoselectivity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Homogeneous palladium-catalyzed Heck vinylation of aryl chlorides was investigated under air using Herrmanns palladacycle and the P(t-Bu)3-liberating salt [(t-Bu)3PH]BF4. Based on the results, controlled microwave heating was utilized to accelerate model Heck reactions with aryl chlorides down to 30 min employing an electron-poor olefin and a mixture of an ionic liquid and 1,4-dioxane as solvent. For the first time, a highly regioselective general protocol has been developed for palladium-...

Datta, Gopal K.

2008-01-01

284

Antikinetoplastid activity of 3-aryl-5-thiocyanatomethyl-1,2,4-oxadiazoles.  

Science.gov (United States)

A series of 5-thiocyanatomethyl- and 5-alkyl-3-aryl-1,2,4-oxadiazoles were synthesized and evaluated for their activity against kinetoplastid parasites. Formation of the oxadiazole ring was accomplished through the reaction of benzamidoximes with acyl chlorides, while the thiocyanate group was inserted by reacting the appropriate 5-halomethyl oxadiazole with ammonium thiocyanate. The thiocyanate-containing compounds possessed low micromolar activity against Leishmania donovani and Trypanosoma brucei, while the 5-alkyl oxadiazoles were less active against these parasites. 3-(4-Chlorophenyl)-5-(thiocyanatomethyl)-1,2,4-oxadiazole (compound 4b) displayed modest selectivity for L. donovani axenic amastigote-like parasites over J774 macrophages, PC3 prostate cancer cells, and Vero cells (6.4-fold, 3.8-fold, and 9.1-fold, respectively), while 3-(3,4-dichlorophenyl)-5-(thiocyanatomethyl)-1,2,4-oxadiazole (compound 4 h) showed 30-fold selectivity against Vero cells but was not selective against PC3 cells. In a murine model of visceral leishmaniasis, compound 4b decreased liver parasitemia caused by L. donovani by 48% when given in five daily i.v. doses at 5mg/kg and by 61% when administered orally for 5 days at 50 mg/kg. These results indicate that aromatic thiocyanates hold promise for the treatment of leishmanial infections if the selectivity of these compounds can be improved. PMID:15142541

Cottrell, Denise M; Capers, Jeffrey; Salem, Manar M; DeLuca-Fradley, Kate; Croft, Simon L; Werbovetz, Karl A

2004-06-01

285

Synthesis of 1-(4-phenoxyphenyl-3-[5-(substituted aryl-1,3,4-oxadiazol-2-yl]propan-1-ones as safer anti-inflammatory and analgesic agents  

Directory of Open Access Journals (Sweden)

Full Text Available A novel series of 1-(4-phenoxyphenyl-3-[5-(substituted aryl-1,3,4-oxadiazol-2-yl]propan-1-one was synthesized by reaction of 3-(4-phenoxybenzoylpropionic acid with several aryl acid hydrazides in phosphorus oxychloride. The structures of the compounds were supported by IR, 1H- and 13C-NMR, MS data and elemental analysis results. These compounds were tested for their anti-inflammatory, analgesic, ulcerogenic and lipid peroxidation actions. A few compounds were found to have very good anti-inflammatory activity in the carrageenan-induced rat paw edema test, while a fair number of the compounds showed significant analgesic activity in the acetic acid-induced writhing test. These new compounds showed very low ulcerogenic action with reduced malondialdehyde content (MDA, which is one of the by-products of lipid peroxidation.

ASIF HUSAIN

2008-08-01

286

Highly efficient copper-catalyzed N-arylation of nitrogen-containing heterocycles with aryl and heteroaryl halides.  

Science.gov (United States)

New (S)-pyrrolidinylmethylimidazole ligands (4a-c) have been readily synthesized in a straightforward fashion from least expensive starting materials in short steps in high yields. Relatively mild and highly efficient CuI-catalyzed N-arylation procedures for imidazoles with aryl and heteroaryl bromides or chlorides have been developed in the presence of 4a and Cs2CO3. It is important to note that the protocol could tolerate functional groups such as ester, nitrile, nitro, ketone, free hydroxyl, and free primary amine on the aryl halide. The protocol could also be applicable to other pi-electron-rich nitrogen heterocycles (pyrrole, pyrazole, indole, benzimidazole, and triazole), affording the N-arylazoles in good to excellent yields. PMID:17348708

Zhu, Liangbo; Cheng, Liang; Zhang, Yuxi; Xie, Rugang; You, Jingsong

2007-04-13

287

Reactions of isocyanide-substituted dimanganese carbonyl complexes with alkynes. Alkyne-isocyanide coupling and the synthesis of metalated n-substituted pyridines  

Energy Technology Data Exchange (ETDEWEB)

When activated by Me[sub 3]NO in the presence of MeCN, the compounds Mn[sub 2](CO)[sub 9](CNR) (la,b; R = Me, Ph) react with MeO[sub 2]O[sub 2]CC[triple bond]CCO[sub 2]Me to yield the new compounds Mn[sub 2](CO)[sub 8][[mu]-(MeO[sub 2]C)C=C(CO[sub 2]Me)C=NR] (2a,b; R = Me, Ph) in yields of 40% and 32%, respectively. Minor products, Mn[sub 2](CO)[sub 7](CNR)[[mu]-(MeO[sub 2]C)C=C(CO[sub 2]Me)-C=O] (3a,b; R = Me, Ph) were also formed. Compound 2a was characterized crystallographically. The structure shows that the isocyanide ligand was coupled to the alkyne, and the nitrogen atom is coordinated to one of the manganese atoms to form a five-membered cyclo-mangana enimine ring. One of the carboxylate groups is coordinated to the other manganese atom. The compounds (4a), (4b), and (4c) were prepared in yields of 27%, 32%, and 31%, respectively, by treatment of 2a,b with C[sub 2]H[sub 2], and of 2a with HC[sub 2](CO[sub 2]Me) in the presence of UV irradiation. Compound 4a was characterized crystallographically. This compound contains a metalated N-methylpyridine ring formed by a 1,4-cycloaddition of the alkyne to the enimine grouping in compound 2a. One of the metal atoms was shifted to a n-bonding coordination involving four of the carbon atoms of the pyridine ring. 14 refs., 2 figs., 7 tabs.

Adams, R.D.; Huang, M. (Univ. of South Carolina, Columbia, SC (United States))

1995-01-01

288

Design, synthesis and antiviral potential of 14-aryl/heteroaryl-14H-dibenzo[a,j]xanthenes using an efficient polymer-supported catalyst.  

Science.gov (United States)

Polyethyleneglycol bound sulfonic acid (PEG-OSO?H), a chlorosulphonic acid-modified polyethylene glycol was successfully used as an efficient and eco-friendly polymeric catalyst in the synthesis of 14-aryl/heteroaryl-14H-dibenzo[a,j]xanthenes obtained from the reaction of 2-naphthol and carbonyl compounds under solvent-free conditions with short reaction times and excellent yields. The biological properties of these synthesized title compounds revealed that compounds 3b, 3c, 3f and 3i showed highly significant anti-viral activity against tobacco mosaic virus. PMID:22710828

Reddi Mohan Naidu, Kalla; Satheesh Krishna, Balam; Anil Kumar, Mungara; Arulselvan, Palanisamy; Ibrahim Khalivulla, Shaik; Lasekan, Ola

2012-01-01

289

Design, molecular modeling, synthesis, and anti-HIV-1 activity of new indolyl aryl sulfones. Novel derivatives of the indole-2-carboxamide.  

Science.gov (United States)

Molecular modeling studies and an updated highly predictive 3-D QSAR model led to the discovery of exceptionally potent indolyl aryl sulfones (IASs) characterized by the presence of either a pyrrolidyn-2-one nucleus at the indole-2-carboxamide or some substituents at the indole-2-carbohydrazide. Compounds 7 and 9 were found active in the sub-nanomolar range of concentration in both MT-4 and C8166 cell-based anti-HIV assays. These compounds, and in particular compound 9, also showed excellent inhibitory activity against both HIV-112 and HIV-AB1 primary isolates in lymphocytes and against HIV WT in macrophages. PMID:16722636

Ragno, Rino; Coluccia, Antonio; La Regina, Giuseppe; De Martino, Gabriella; Piscitelli, Francesco; Lavecchia, Antonio; Novellino, Ettore; Bergamini, Alberto; Ciaprini, Chiara; Sinistro, Anna; Maga, Giovanni; Crespan, Emanuele; Artico, Marino; Silvestri, Romano

2006-06-01

290

Induction of Mouse UDP-Glucuronosyltransferase mRNA Expression in Liver and Intestine by Activators of Aryl-Hydrocarbon Receptor, Constitutive Androstane Receptor, Pregnane X Receptor, Peroxisome Proliferator-Activated Receptor ?, and Nuclear Factor Erythroid 2-Related Factor 2  

Digital Repository Infrastructure Vision for European Research (DRIVER)

UDP-glucuronosyltransferases (UGTs) catalyze the addition of UDP-glucuronic acid to endo- and xenobiotics, enhancing their water solubility and elimination. Many exogenous compounds, such as microsomal enzyme inducers (MEIs), alter gene expression through xenobiotic-responsive transcription factors, namely, the aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor ? (PPAR?), and ...

Buckley, David B.; Klaassen, Curtis D.

2009-01-01

291

Efficient Synthesis of 3H-Indoles Enabled by the Lead-Mediated ?-Arylation of ?-Ketoesters or ?-Lactams Using Aryl Azides.  

Science.gov (United States)

The development of a lead-mediated ?-arylation reaction between aryl azides and ?-ketoesters or ?-lactams that facilitates the formation of 3H-indoles is disclosed. Twenty-five examples are included which demonstrate the generality of this reaction to access aryl azides bearing tetrasubstituted o-alkyl substituents. When paired with a Staudinger reduction, this reaction streamlines the synthesis of functionalized 3H-indoles. PMID:24865180

Zhou, Fei; Driver, Tom G

2014-06-01

292

Synthesis of thiophene oligomers via organotin compounds  

International Nuclear Information System (INIS)

2-Trimethylstannylterthiophene coupes with functionalized aryl bromides and substituted bromothiophenes in the presence Bis (triphenylphenylphosphine) palladium (II) chloride to give substituted terthiophenes and substituted quaterthiophenes, respectively. Also, 3-trimethylstannylthiophene and 2-trimethylstannylthiophene couple with substituted 2,5-dibromothiophenes to give substituted branched terthiophenes and substituted ?-terthiophenes, respectively. The structures of the new compounds were confirmed by elemental analysis, mass spectrometry, and H-NMR spectral data. (authors). 18 refs., 2 figs

2000-01-01

293

Different Reaction Patterns in the Baylis-Hillman Reaction of Aryl Aldehydes with Phenyl Vinyl Ketone, Phenyl Acrylate and Phenyl Thioacrylate  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the Baylis-Hillman reaction of aryl aldehydes with phenyl vinyl ketone we have observed exclusive formation of diadducts 4, and that the yields of diadduct can reach 80% with increasing amounts of phenyl vinyl ketone. On the other hand, for phenyl acrylate and phenyl thioacrylate, only the normal Baylis-Hillman adduct was obtained. The effects of substituents were also examined and a plausible reaction mechanism is proposed for the formation of compounds 4.

Min Shi; Chao-Qun Li; Jian-Kang Jiang

2002-01-01

294

The aryl hydrocarbon receptor-mediated disruption of vitellogenin synthesis in the fish liver: Cross-talk between AHR- and ER?-signalling pathways  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background In the fish liver, the synthesis of egg yolk protein precursor vitellogenin (VTG) is under control of the estrogen receptor alpha (ER?). Environmental contaminants such as 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) are suspected to have antiestrogenic effects. The aryl hydrocarbon receptor (AHR) is the initial cellular target for TCDD and related compounds. The AHR is a ligand-activated transcription factor that stimulates the expression of the ...

2004-01-01

295

Different Reaction Patterns in the Baylis-Hillman Reaction of Aryl Aldehydes with Phenyl Vinyl Ketone, Phenyl Acrylate and Phenyl Thioacrylate  

Directory of Open Access Journals (Sweden)

Full Text Available In the Baylis-Hillman reaction of aryl aldehydes with phenyl vinyl ketone we have observed exclusive formation of diadducts 4, and that the yields of diadduct can reach 80% with increasing amounts of phenyl vinyl ketone. On the other hand, for phenyl acrylate and phenyl thioacrylate, only the normal Baylis-Hillman adduct was obtained. The effects of substituents were also examined and a plausible reaction mechanism is proposed for the formation of compounds 4.

Jian-Kang Jiang

2002-10-01

296

Inhibition of cytochrome P4501-dependent clearance of the endogenous agonist FICZ as a mechanism for activation of the aryl hydrocarbon receptor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Altered systemic levels of 6-formylindolo[3,2-b]carbazole (FICZ), an enigmatic endogenous ligand for the aryl hydrocarbon receptor (AHR), may explain adverse physiological responses evoked by small natural and anthropogenic molecules as well as by oxidative stress and light. We demonstrate here that several different chemical compounds can inhibit the metabolism of FICZ, thereby disrupting the autoregulatory feedback control of cytochrome P4501 systems and other proteins whose expression is r...

Wincent, Emma; Bengtsson, Johanna; Bardbori, Afshin Mohammadi; Alsberg, Tomas; Luecke, Sandra; Rannug, Ulf; Rannug, Agneta

2012-01-01

297

Mechanistic and Computational Studies of Oxidatively-Induced ArylCF3 Bond-Formation at Pd: Rational Design of Room Temperature Aryl Trifluoromethylation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article describes the rational design of 1st generation systems for oxidatively-induced ArylCF3 bond-forming reductive elimination from PdII. Treatment of (dtbpy)PdII(Aryl)(CF3) (dtbpy = di-tert-butylbipyridine) with NFTPT (N-fluoro-1,3,5-trimethylpyridium triflate) afforded the isolable PdIV intermediate (dtbpy)PdIV(Aryl)(CF3)(F)(OTf). Thermolysis of this complex at 80 C resulted in ArylCF3 bond-formation. Detailed experimental and computational mechanistic studies have been con...

Ball, Nicholas D.; Brannon Gary, J.; Ye, Yingda; Sanford, Melanie S.

2011-01-01

298

Synthesis and anticonvulsant activity of 4-(2-(2,6-dimethylphenylamino)-2-oxoethylamino)-N-(substituted)butanamides: a pharmacophoric hybrid approach.  

Science.gov (United States)

A series of pharmacophoric hybrids of ameltolide-gamma-aminobutyric acid (GABA)-amides was designed, synthesized, and evaluated for their anticonvulsant and neurotoxic properties. Initial anticonvulsant screening was performed using intraperitoneal (ip) maximal electroshock-induced seizure (MES), subcutaneous pentylenetetrazole (scPTZ), and subcutaneous picrotoxin (scPIC)-induced seizure threshold tests. All the compounds had improved lipophilicity and the pharmacological activity profile confirmed their blood-brain barrier penetration. The titled compounds showed promising activity in scPIC screen indicating the involvement of GABA-mediation. Compound 4-(2-(2,6-dimethylaminophenylamino)-2-oxoethylamino)-N-(2,6-dimethylphenyl) butanamide (7) emerged as the most potent derivative effective in all the three animal models of seizure with no neurotoxicity at the anticonvulsant dose. PMID:17481896

Yogeeswari, Perumal; Sriram, Dharmarajan; Sahitya, Puppala; Ragavendran, Jegadeesan Vaigunda; Ranganadh, Velagaleti

2007-07-01

299

Synthesis, Characterization and Antibacterial Activity of New 1,2- and 1,4-Bis(N' -Substituted Thioureido)benzene Derivatives  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english Synthesis of two series of 1,2- and 1,4-bis(thioureido)benzene derivatives was accomplished by the treatment of corresponding alkanoyl/aroyl chlorides with potassium thiocyanate in dry acetone to afford the respective isothiocyanates as intermediates. The latter were treated in situ with 1,2- and 1, [...] 4-diaminobenzene, respectively, to afford the title compounds in high yields. A total of sixteen new compounds are reported herein. The structures of the products were confirmed by spectroscopic techniques (IR, H and 13C NMR, mass spectrometry), elemental analysis and in case of 1d, by X-ray diffraction technique. All the synthesized compounds were also subjected to antibacterial bioevaluation against ten different Gram-positive and Gram-negative bacterial strains using levofloxacin as the standard drug and were shown to possess promising activities.

Aamer, Saeed; Naeem, Abbas; Zaman, Ashraf; Michael, Bolte.

300

Bis-aryl substituted dioxaborines as electron-transport materials: a comparative density functional theory investigation with oxadiazoles and siloles  

Energy Technology Data Exchange (ETDEWEB)

We report on a detailed quantum-chemical comparison of the electronic structures, vertical electron affinities, and intramolecular reorganization energies for bis-aryl substituted dioxaborine, oxadiazole, and silole derivatives. The results indicate that the HOMO and LUMO energies of the substituted compounds can be tuned on the order of 2-3 eV via minor changes in the substitution patterns, with the HOMO and LUMO levels for the dioxaborine derivatives consistently the most energy stabilized. Additionally, large vertical electron affinities and comparable intramolecular reorganization energies confirm that dioxaborine systems are interesting candidates for electron transport materials.

Risko, C. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); Zojer, E. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); Brocorens, P. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); Marder, S.R. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); Bredas, J.L. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States)], E-mail: jean-luc.bredas@chemistry.gatech.edu

2005-06-27

 
 
 
 
301

Bis-aryl substituted dioxaborines as electron-transport materials: a comparative density functional theory investigation with oxadiazoles and siloles  

International Nuclear Information System (INIS)

We report on a detailed quantum-chemical comparison of the electronic structures, vertical electron affinities, and intramolecular reorganization energies for bis-aryl substituted dioxaborine, oxadiazole, and silole derivatives. The results indicate that the HOMO and LUMO energies of the substituted compounds can be tuned on the order of 2-3 eV via minor changes in the substitution patterns, with the HOMO and LUMO levels for the dioxaborine derivatives consistently the most energy stabilized. Additionally, large vertical electron affinities and comparable intramolecular reorganization energies confirm that dioxaborine systems are interesting candidates for electron transport materials

2005-06-27

302

Bis-aryl substituted dioxaborines as electron-transport materials: a comparative density functional theory investigation with oxadiazoles and siloles  

Science.gov (United States)

We report on a detailed quantum-chemical comparison of the electronic structures, vertical electron affinities, and intramolecular reorganization energies for bis-aryl substituted dioxaborine, oxadiazole, and silole derivatives. The results indicate that the HOMO and LUMO energies of the substituted compounds can be tuned on the order of 2-3 eV via minor changes in the substitution patterns, with the HOMO and LUMO levels for the dioxaborine derivatives consistently the most energy stabilized. Additionally, large vertical electron affinities and comparable intramolecular reorganization energies confirm that dioxaborine systems are interesting candidates for electron transport materials.

Risko, C.; Zojer, E.; Brocorens, P.; Marder, S. R.; Brdas, J. L.

2005-06-01

303

Substituted N-aryl-6-pyrimidinones: A new class of potent, selective, and orally active p38 MAP kinase inhibitors  

Energy Technology Data Exchange (ETDEWEB)

A novel series of highly potent and selective p38 MAP kinase inhibitors was developed originating from a substituted N-aryl-6-pyrimidinone scaffold. SAR studies coupled with in vivo evaluations in rat arthritis model culminated in the identification of 10 with excellent oral efficacy. Compound 10 exhibited a significantly enhanced dissolution rate compared to 1, translating to a high oral bioavailability (>90%) in rat. In animal studies 10 inhibited LPS-stimulated production of tumor necrosis factor-{alpha} in a dose-dependent manner and demonstrated robust efficacy comparable to dexamethasone in a rat streptococcal cell wall-induced arthritis model.

Devadas, Balekudru; Selness, Shaun R.; Xing, Li; Madsen, Heather M.; Marrufo, Laura D.; Shieh, Huey; Messing, Dean M.; Yang, Jerry Z.; Morgan, Heidi M.; Anderson, Gary D.; Webb, Elizabeth G.; Zhang, Jian; Devraj, Rajesh V.; Monahan, Joseph B. (Pfizer)

2012-02-28

304

Methanofullerene-Based Palladium Bis(amino)aryl Complexes and Applications in Lewis Acid Catalysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Synthetic routes have been developed for the attachment of palladium(II) bis(amino)aryl (NCN or C6H2{CH2NMe2}2-2,6)- complexes to C60. Using diazo and Bingel addition reactions, various methanofullerene NCN-SiMe3 compounds (C60-L-NCN-SiMe3, L = C(Me), C(CO2Et)CO2CH2, and C(Me)C6H4CC) have been prepared and characterized. Electrophilic palladation of these ligands was achieved with Pd(OAc)2, leading to the corresponding C60-L-NCNPdCl complexes. These were converted into active Lewis acid cat...

2001-01-01

305

2-Aryl-3H-indol-3-ones: synthesis, electrochemical behaviour and antiplasmodial activities.  

Science.gov (United States)

The synthesis of indolone derivatives and their antiplasmodial activity invitro against Plasmodium falciparum at the blood stage are described. The 2-aryl-3H-indol-3-ones were synthesized via deoxygenation of indolone-N-oxides. Electrochemical behaviour, antiplasmodial activity and cytotoxicity on human tumor cell lines were compared to those of indolone-N-oxides. The antiplasmodial IC50 (concentrations at 50% inhibition) of these compounds ranged between 49 and 1327nM. Among them, the 2-(4-dimethylaminophenyl)-5-methoxy-indol-3-one, 7, had the best antiplasmodial activity invitro (IC50=49nM; FcB1 strain) and selectivity index (SI (CC50 MCF7/IC50 FcB1)=423.4). Thus, the hits identified in this deoxygenated series correspond to their structural homologs in the N-oxide series with comparable electrochemical behaviour at the nitrogen-carbon double bond. PMID:24686013

Najahi, Ennaji; Valentin, Alexis; Fabre, Paul-Louis; Reybier, Karine; Nepveu, Franoise

2014-05-01

306

Novel 4-aryl-pyrido[1,2-c]pyrimidines with dual SSRI and 5-HT1A activity: part 2.  

Science.gov (United States)

Derivatives of 4-aryl-5,6,7,8-tetrahydro-pyrido[1,2-c]pyrimidine were synthesized. These compounds contain the 3-(4-piperidyl)-1H-indole residue or its 5-methoxy or 2-methyl derivative. In vitro binding tests were performed to determine the affinity of the compounds for the 5-HT(1A) receptor and serotonin transporter (SERT) proteins in the rat brain cortex. In vivo studies, particularly the inducible hypothermia test and forced swimming test, were conducted to determine agonistic/antagonistic activity with pre- and postsynaptic 5-HT(1A) receptors. Molecular modeling techniques were used to determine the binding modes of the selected compounds at the 5-HT(1A) receptor and SERT. The SAR analysis showed that the presence of the 3-(4-piperidyl)-1H-indole group or its 5-methoxy derivative, as well as a para substitution with -OCH(3) or -F in the aryl ring of 4-aryl-5,6,7,8-tetrahydro-pyrido[1,2-c]pyrimidine, results in an increased affinity for both the 5-HT(1A) receptors and SERT. In contrast, the presence of the 2-methyl-3-(4-piperidyl)-1H-indole group resulted in a considerable decrease in binding affinity. PMID:19665823

Herold, Franciszek; Izbicki, ?ukasz; Chodkowski, Andrzej; Dawidowski, Maciej; Krl, Marek; Kleps, Jerzy; Tur?o, Jadwiga; Wolska, Irena; Nowak, Gabriel; Stachowicz, Katarzyna; Dyba?a, Ma?gorzata; Siwek, Agata; Nowak, Mateusz; Pieniazek, Elzbieta; Jaro?czyk, Ma?gorzata; Sylte, Ingebrigt; Mazurek, Aleksander P

2009-11-01

307

PHOTOLYSIS OF ARYL KETONES WITH VARYING VAPOR PRESSURE ON SOIL  

Science.gov (United States)

The photolysis of a series of aryl ketones on air-dried soil surfaces was examined to establish whether vapor transport has an effect on the rate and extent of photolysis. f vapor transport were significant on light-exposed soils, then differences in the observed photolysis rate ...

308

One-Pot Arylative Epoxidation of Ketones Employing Amphoteric Bromoperfluoroarenes**  

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A one-pot cascade arylative epoxidation of enolizable ketones with bromopentafluorobenzene (PFPBr) and derivatives into perfluoroaryl oxiranes is reported. PFPBr is utilized as an equivalent of Br+ and PFP? in this highly efficient, easily scaled up and diastereoselective epoxidation reaction, which produces synthetically useful polyfluoroaryl oxiranes.

Li, Zhou; Gevorgyan, Vladimir

2012-01-01

309

The Aryl Hydrocarbon Receptor: A Target for Breast Cancer Therapy  

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The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates a battery of genes in response to exposure to a broad class of environmental poly aromatic hydrocarbons (PAH). AhR is historically characterized for its role in mediat...

Powell, Joann B.; Goode, Gennifer D.; Eltom, Sakina E.

2013-01-01

310

Palladium-catalyzed direct arylation of indoles with cyclohexanones.  

Science.gov (United States)

A novel palladium catalyzed approach to 3-arylindoles was developed from indoles and cyclohexanones. Various cyclohexanones acted as aryl sources via an alkylation and dehydrogenation sequence using molecular oxygen as the hydrogen acceptor. This method showed good regioselectivity and afforded 3-arylindoles as the sole products. PMID:24597845

Chen, Shanping; Liao, Yunfeng; Zhao, Feng; Qi, Hongrui; Liu, Saiwen; Deng, Guo-Jun

2014-03-21

311

Synthesis and Toxicity Evaluation of Some N4-Aryl Substituted 5-Trifluoromethoxyisatin-3-thiosemicarbazones  

Directory of Open Access Journals (Sweden)

Full Text Available A series of twenty one N4-aryl substituted 5-trifluoromethoxyisatin-3-thiosemicarbazones 3a-3u was synthesized by the reaction of trifluoromethoxyisatin 1 with different arylthiosemicarbazides 2 in aqueous ethanol (50%, containing a few drops of acetic acid. Their structures were established on the basis of analytical (CHN and spectral (IR, 1H-NMR, EIMS data. All the synthesized compounds were evaluated for their toxicity potential by a brine shrimp lethality bioassay. Ten compounds i.e., 3a, 3e, 3i-3l and 3n-3q proved to be active in this assay, displaying promising toxicity (LD50 = 1.11 10?5 M ? 1.80 10?4 M. Amongst these, 3k, 3n and 3o were found to be the most active ones (LD50 = 1.11 10?5 M ? 1.43 10?5 M. Compound 3k showed the highest activity with a LD50 value of 1.11 10?5 M and can, therefore, be used as a lead for further studies. Structure-activity relationship (SAR studies revealed that the presence of strong inductively electron-attracting trifluoromethoxy substituent at position-5 of the isatin moiety played an important role in inducing or enhancing toxic potentiality of some of the synthesized compounds.

Muhammad Yaqub

2011-07-01

312

Characterization of natural aryl hydrocarbon receptor agonists from cassia seed and rosemary.  

Science.gov (United States)

Many recent studies have suggested that activation of the aryl hydrocarbon receptor (AhR) reduces immune responses, thus suppressing allergies and autoimmune diseases. In our continuing study on natural AhR agonists in foods, we examined the influence of 37 health food materials on the AhR using a reporter gene assay, and found that aqueous ethanol extracts of cassia seed and rosemary had particularly high AhR activity. To characterize the AhR-activating substances in these samples, the chemical constituents of the respective extracts were identified. From an active ethyl acetate fraction of the cassia seed extract, eight aromatic compounds were isolated. Among these compounds, aurantio-obtusin, an anthraquinone, elicited marked AhR activation. Chromatographic separation of an active ethyl acetate fraction of the rosemary extract gave nine compounds. Among these compounds, cirsimaritin induced AhR activity at 10-10 ?M, and nepitrin and homoplantagenin, which are flavone glucosides, showed marked AhR activation at 10-10 ?M. PMID:24747651

Amakura, Yoshiaki; Yoshimura, Morio; Takaoka, Masashi; Toda, Haruka; Tsutsumi, Tomoaki; Matsuda, Rieko; Teshima, Reiko; Nakamura, Masafumi; Handa, Hiroshi; Yoshida, Takashi

2014-01-01

313

Synthesis and in-vitro antibacterial activity of some alkoxy based N-substituted-5-(furan-2-yl)-phenyl-bis-pyrazolines  

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Bis-pyrazoline darivatives (2a-e) built around the alkyl chains of varying length were synthesized in good yield by refluxing bis-chalcones (1a-e) with phenyl hydrazine in CH3COOH and ethanol. The structures of these compounds were elucidated by IR, 1H NMR, 13C...

Mamta Rani; Mohamad Yusuf

2012-01-01

314

Synthesis and in vitro antibacterial activity of N-methylnitrone and nitrovinyl derivatives of some N-substituted 2-chloroindol-3-carboxaldehydes  

Energy Technology Data Exchange (ETDEWEB)

N-methylnitrones and nitrovinyl derivatives from 1-substituted-2-chloroindol-3-carboxaldehydes were synthesized and evaluated for their in vitro antibacterial activity. Some nitrovinyl derivatives displayed good in vitro activity against Gram-positive bacteria; the compound (II e), 1-(o-chlorobenzyl)-2-chloro-3-(2-nitroethenyl)indole, was more active than nitrofurantoin against Staphylococcus aureus and Streptococcus pyogenes. Some structure-activity relationships are discussed.

Gatti, R.; Cavrini, V.; Roveri, P.; Bianucci, F.; Legnani, P.

1981-02-01

315

N-substituted piperazinopyridylsteroid derivatives as abiraterone analogues inhibit growth and induce pro-apoptosis in human hormone-independent prostate cancer cell lines.  

Science.gov (United States)

Nine new 17-(piperazin-1-yl)pyridin-5-yl)steroids as abiraterone analogues were synthesized. Compounds 5d and 5g showed selective activities against 17?-hydroxylase/C17,20-lyase (CYP17A1) and aromatase (CYP19), respectively. IC50 values of 5d were 5.09 and >50? ?m, whereas these values for 5g were >50 ??m and 7.40 ?m, respectively, for CYP17A1 and CYP19. Molecular modelling highlighted that the inhibitor designed to bind cytochrome P450 haem iron is a necessary condition but not the only rationale to explain inhibitory activity. These abiraterone analogues were then evaluated on hormone-independent prostate cancer cell lines DU-145 and PC-3 and on hormone-dependent breast and prostate cancer cell lines MCF-7 and LNCaP, respectively. Compounds 5e, 5g and 5i have showed potent activities only on hormone-independent prostate cancer cell lines DU-145 and PC-3 with 60-85% inhibition of both cell viability and growth at 10 nm with pro-apoptotic mechanism as illustrated in PC-3 cells by DNA ladder assay and Western blotting of Bax, Casp-3 and its substrate, the poly (ADP-ribose) polymerase. We conclude that hybrid heterocycle steroids could be good lead compounds in the drug design especially against hormone-independent prostate cancer. PMID:23906044

Brossard, Dominique; Zhang, Ying; Haider, Shozeb M; Sgobba, Miriam; Khalid, Mohamed; Legay, Rmi; Duterque-Coquillaud, Martine; Galera, Philippe; Rault, Sylvain; Dallemagne, Patrick; Moslemi, Safa; El Kihel, Lala

2013-11-01

316

Rhodium/diene-catalyzed asymmetric arylation of N-sulfonyl indolylimines: a new access to highly optically active ?-aryl 3-indolyl-methanamines.  

Science.gov (United States)

A new and efficient method for the preparation of highly enantiomerically enriched ?-aryl 2- or 3-indolyl-methanamines by rhodium-catalyzed asymmetric arylation of N-sulfonyl indolylimines with arylboronic acids using chiral bicyclo[3.3.0] diene was developed. PMID:21060928

Yang, Hong-Yu; Xu, Ming-Hua

2010-12-28

317

Rhodium-catalyzed synthesis of unsymmetrical di(aryl/heteroaryl)methanes using aryl/heteroarylmethyl ketones via CO-C bond cleavage.  

Science.gov (United States)

RhH(PPh3)4 and 1,2-bis(diphenylphosphino)benzene catalyze the reaction of aryl/heteroarylmethyl ketones and aryl heteroaryl ethers giving unsymmetrical diarylmethanes containing one or two heteroarenes in high yields. The reaction does not use alkali metal bases, and therefore does not form large amounts of metal waste. PMID:24643329

Li, Guangzhe; Arisawa, Mieko; Yamaguchi, Masahiko

2014-04-28

318

(E)-4-aryl-4-oxo-2-butenoic acid amides, chalcone-aroylacrylic acid chimeras: Design, antiproliferative activity and inhibition of tubulin polymerization  

Science.gov (United States)

Antiproliferative activity of twenty-nine (E)-4-aryl-4-oxo-2-butenoic acid amides against three human tumor cell lines (HeLa, FemX, and K562) is reported. Compounds showed antiproliferative activity in one-digit micromolar to submicromolar concentrations. The most active derivatives toward all the cell lines tested bear alkyl substituents on the aroyl moiety of the molecules. Fourteen compounds showed tubulin assembly inhibition at concentrations <20 ?M. The most potent inhibitor of tubulin assembly was unsubstituted compound 1, with IC50 = 2.9 ?M. Compound 23 had an oral LD50 in vivo of 45 mg/kg in mice. Cell cycle analysis on K562 cells showed that compounds 1, 2 and 23 caused accumulation of cells in the G2/M phase, but inhibition of microtubule polymerization is not the principal mode of action of the compounds. Nevertheless, they may be useful leads for the design of a new class of antitubulin agents.

Vitorovic-Todorovic, Maja D.; Eric-Nikolic, Aleksandra; Kolundzija, Branka; Hamel, Ernest; Ristic, Slavica; Juranic, Ivan O.; Drakulic, Branko J.

2013-01-01

319

Iron-catalyzed C-H bond activation for the ortho-arylation of aryl pyridines and imines with Grignard reagents.  

Science.gov (United States)

Direct arylation of the ortho-C-H bond of an aryl pyridine or an aryl imine with an aryl Grignard reagent has been achieved by using an iron-diamine catalyst and a dichloroalkane as an oxidant in a short reaction time (e.g., 5 min) under mild conditions (0 C). The use of an aromatic co-solvent, such as chlorobenzene and benzene, and slow addition of the Grignard reagent are essential for the high efficiency of the reaction. The present arylation reaction has distinct merits over the previously developed reaction that used an arylzinc reagent, such as its reaction rate and atom economy. Selective C-H bond activation occurs in the presence of a leaving group, such as a tosyloxy, chloro, and bromo group. Studies on a stoichiometric reaction and kinetic isotope effects shed light on the reaction intermediate and the C-H bond-activation step. PMID:21898839

Yoshikai, Naohiko; Asako, Sobi; Yamakawa, Takeshi; Ilies, Laurean; Nakamura, Eiichi

2011-11-01

320

Synthesis, X-ray crystal structure and optical properties of novel 5-(3-aryl-1 H-pyrazol-5-yl)-2-(6-methoxy-3-methylbenzofuran-2-yl)-1,3,4-oxadiazole  

Science.gov (United States)

A series of novel 5-(3-aryl-1 H-pyrazol-5-yl)-2-(6-methoxy-3-methylbenzofuran-2-yl)-1,3,4-oxadiazole derivatives has been synthesized from 6-methoxy-3-methylbenzofuran-2-carboxylic acid and ethyl 3-aryl-1 H-pyrazole-5-carboxylate. The structures of compounds obtained were determined by IR, 1H NMR and HRMS spectra. Typically, the spatial structure of compound 7e was determined by using X-ray diffraction analysis. UV-vis absorption and fluorescence spectral characteristics of the compounds in dichloromethane and acetonitrile were investigated. The results showed that the absorption maxima of the compounds vary from 321 to 339 nm depending on the substituents in N-1 position of pyrazole moiety and para position of benzene moiety. The maximum emission spectra of compounds in two different solvents were mainly dependent on groups in N-1 position of pyrazole moiety. The intensity of absorption and fluorescence was also correlated with substituents on the aryl ring bonded to pyrazole moiety. In addition, the absorption and emission spectra of these compounds change with increasing solvent polarity.

Jiang, Zhen-Ju; Liu, Jin-Ting; Lv, Hong-Shui; Zhao, Bao-Xiang

2012-02-01

 
 
 
 
321

Radioiodination of Aryl-Alkyl Cyclic Sulfates  

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Among the currently available positron emitters suitable for Positron Emission Tomography (PET), 124I has the longest physical half-life (4.2 days). The long half-life and well-investigated behavior of iodine in vivo makes 124I very attractive for pharmacological studies. In this communication, we describe a simple yet effective method for the synthesis of novel 124I labeled compounds intended for PET imaging of arylsulfatase activity in vivo. Arylsulfatases have important biological function...

Chandra Mushti; Papisov, Mikhail I.

2012-01-01

322

Synthesis, crystal Structures and aggregation-induced emission enhancement of aryl-substituted cyclopentadiene derivatives  

International Nuclear Information System (INIS)

A series of cyclopentadiene derivates, namely, 1,2,4-triphenylcyclopenta-1,3-diene (1), 1,2-diphenyl-4-(p-methoxyphenyl)cyclopenta-1,3-diene (2) and 1,2-di(p-methoxyphenyl)-4-phenylcyclopenta-1,3-diene (3), were synthesized and their photoluminescence properties in solutions and aggregation state were investigated. Different photoluminescence properties of 13 were tuned by changing types and replace position of substituent groups. These cyclopentadiene derivates display solvent-dependent fluorescence emissions and typical aggregation-induced emission enhancement (AIEE) characteristics. The crystal structure analysis reveals that intermolecular CH? interactions and X-aggregation molecule stacking have a dramatic effect on the photoluminescent properties of 13. Additionally, the DFT calculations of these compounds were investigated. -- Graphical abstract: A series of aryl-substituted cyclopentadiene derivatives with AIEE properties were synthesized and their crystal structures and photoluminescence properties in solution and aggregation state were studied. Highlights: ? A series of cyclopentadiene derivates were synthesized via aldol condensation followed cyclizing and dehydrating reaction. ? The effect of solvents on fluorescence properties of these compounds were investigated in seven organic solvents. ? These compounds show typical aggregation-induced emission enhancement properties

2013-07-01

323

Antibacterials. Synthesis and structure-activity studies of 3-aryl-2-oxooxazolidines. 1. The "B" group.  

Science.gov (United States)

The synthesis and structure/activity studies of the effect of varying the "B" group in a series of oxazolidinone antibacterials (I) are described. Two synthetic routes were used: (1) alkylation of aniline with glycidol followed by dialkyl carbonate heterocyclization to afford I (A = H, B = OH), whose arene ring was further elaborated by using electrophilic aromatic substitution methodology; (2) cycloaddition of substituted aryl isocyanates with epoxides to give A and B with a variety of values. I with B = OH or Br were converted to other "B" functionalities by using SN2 methodology. Antibacterial evaluation of compounds I with A = acetyl, isopropyl, methylthio, methylsulfinyl, methylsulfonyl, and sulfonamido and a variety of different "B" groups against Staphylococcus aureus and Enterococcus faecalis concluded that the compounds with B = aminoacyl, and particularly acetamido, were the most active of those examined in each A series, possessing MICs in the range of 0.5-4 micrograms/mL for the most active compounds described. PMID:2502627

Gregory, W A; Brittelli, D R; Wang, C L; Wuonola, M A; McRipley, R J; Eustice, D C; Eberly, V S; Bartholomew, P T; Slee, A M; Forbes, M

1989-08-01

324

Two anionic [Cu I6X7] nn- ( X=Br and I) chain-based organic-inorganic hybrid solids with N-substituted benzotriazole ligands  

Science.gov (United States)

Solvothermal reactions of the flexible ligand 1,6-Bi(benzotriazole)hexane with CuI and KI or CuBr and KBr in ethanol generate two hybrid compounds, namely, {(HETA)[(Cu 6I 7)(ETA) 2]} n( 1) and {K(Cu 6Br 7)(BBTH)} n( 2) (ETA= N-ethylbenzotriazole, HETA=protonated N-ethylbenzotriazole, BBTH=1,6-bi(benzotriazole)hexane). In 1, two [Cu 3I 4] vertex missing cubane-like subunits link each other by sharing one I atom to give a [Cu 6I 7] cluster, which further form novel 1D [Cu 6I 7] nn- anionic chain. Two in-situ generated ETA ligands finished the 4-coordinated environments of copper centers and another one discrete protonated ETA ligand keeps the charge neutrality for 1. In complex 2, bowl-shaped [Cu 5Br 4] clusters and rhomboid [Cu 2Br 2] dimers link each other to generate a [Cu 6Br 7] nn- 1D chain. BBTH ligands complete the tetrahedral spheres of Cu(I), and 7-coordinated K atoms further extend the 1D chain motifs to a 2D hybrid layer of 2. The UV-vis diffuse reflectance spectrum and luminescence measurements show that compound 1 and 2 both are potential semiconductor and photoluminescence materials.

Gao, Xia; Zhai, Quan-Guo; Li, Shu-Ni; Xia, Rui; Xiang, Hai-Juan; Jiang, Yu-Cheng; Hu, Man-Cheng

2010-05-01

325

Carbonic anhydrase inhibitors. Synthesis, and molecular structure of novel series N-substituted N'-(2-arylmethylthio-4-chloro-5-methylbenzenesulfonyl)guanidines and their inhibition of human cytosolic isozymes I and II and the transmembrane tumor-associated isozymes IX and XII.  

Science.gov (United States)

A series of novel N-substituted N'-(2-arylmethylthio-4-chloro-5-methylbenzenesulfonyl)guanidines 9-41 have been synthesized and investigated as inhibitors of four isoforms of zinc enzyme carbonic anhydrase (CA.EC 4.2.1.1), that is the cytosolic CA I and II, and cancer-associated isozymes CA IX and XII. Against the human CA I investigated compounds showed KI in the range of 87-6506 nM, toward hCA II ranging from 7.8 to 4500 nM, against hCA IX in the range of 4.7-416 nM and against hCA XII at range of 0.96-540 nM. Compounds 10, 12-14, 16, 18-20, 24-26, 31 and 32 exhibited a powerful inhibitory potency toward hCA IX (K(I) = 4.7-21 nM) in comparison to the reference sulfonamides AAZ, MZA, EZA, DCP and IND (K(I) = 24-50 nM). Compound 14 was the most potent inhibitor of hCA I (K(I) = 87 nM), hCA IX (K(I) = 4.7 nM) and hCA XII (K(I) = 0.96 nM), while 26 was the most effective inhibitor of hCA II (K(I) = 7.8 nM). The most promising compound 32 exerted the highest selectivity ratios toward hCA IX versus hCA I (hCA I/hCA IX = 261) and hCA II (hCA II/hCA IX = 26). The in vitro antitumor activity of compounds 10, 13, 14, 21, 22, 25, 32, 38 and 41 was evaluated at the US National Cancer Institute (NCI) against a panel of 60 human tumor cell lines. The most active antitumor agents 21 and 25, inhibiting 32-35 human tumor cell lines with GI?? in the range of 2.1-5.0 ?M also showed relatively high inhibitory activity toward hCA IX and XII with KI from 18 to 40 nM. PMID:24291567

?o?nowska, Beata; S?awi?ski, Jaros?aw; Pogorzelska, Aneta; Chojnacki, Jaros?aw; Vullo, Daniela; Supuran, Claudiu T

2014-01-01

326

Alkyne and alkene complexes of a d(0) zirconocene aryl cation.  

Science.gov (United States)

The generation and properties of nonchelated Zr-aryl-alkyne and Zr-aryl-alkene complexes that are stabilized by the presence of beta-Si-substituents in the alkyne and alkene ligands and fluorination of the aryl ligand are described. Reaction of [Cp'2Zr(OtBu)(ClCD2Cl)][B(C6F5)4] (1, Cp' = C5H4Me) with alkyne and alkene substrates (L) generates Cp'2Zr(OtBu)(L)+ adducts (L = HCCCH2SiMe3 (2); H2C=CHCH2SiMe3 (3); HCCMe (4); H2C=CHCH2CMe3 (5)). Equilibrium constants for substrate binding (Keq = [Zr-L][1]-1[L]-1; CD2Cl2, -89 degrees C) are much larger for the beta-Si-substituted compounds 2 (1.0(2) x 105 M-1) and 3 (1.7(4) x 103 M-1) than for hydrocarbon analogues 4 (3.6(7) x 102 M-1) and 5 (1.9(1) M-1), which is ascribed to beta-Si stabilization of the partial positive charge on Cint of the bound substrate. [Cp2Zr(C6F5)][B(C6F5)4] (7, Cp = C5H5) was generated by the reaction of Cp2Zr(C6F5)Me with [Ph3C][B(C6F5)4] in C6D5Cl. Reaction of 7 with alkyne and alkene substrates (L) generates Cp2Zr(C6F5)(L)+ adducts (L = HCCCH2SiMe3 (8); H2C=CHCH2SiMe3 (10)). No insertion of the substrate into the Zr-C6F5 bond is observed in 8 (at -38 degrees C) or 10 (up to 22 degrees C). The allyltrimethylsilane ligand in 10 undergoes nondissociative alkene face exchange ("alkene flipping", i.e., exchange of the Cp2Zr(C6F5)+ unit between the two alkene enantiofaces without alkene dissociation), with a first-order rate constant kflip = 23(1) s-1 (C6D5Cl, -38 degrees C). 10 also undergoes slower reversible decomplexation of the alkene (kdissoc = 5.0(8) s-1; C6D5Cl, -38 degrees C). PMID:15355096

Stoebenau, Edward J; Jordan, Richard F

2004-09-15

327

Synthesis, Structure and Antifungal Activity of New 3-[(5-Aryl-1,3,4-oxadiazol-2-ylmethyl]benzo[d]thiazol-2(3H-ones  

Directory of Open Access Journals (Sweden)

Full Text Available A series of new 3-[(5-aryl-1,3,4-oxadiazol-2-ylmethy]benzo[d]thiazol-2(3H-ones were synthesized by reaction of (5-substituted-2-oxobenzothiazolin-3-yl-acetohydrazide with various aromatic acids in POCl3 under reflux conditions. The structures of the title compounds were confirmed by 1H-NMR, 13C-NMR, IR, MS and elemental analysis. Furthermore, the structure of compound 4i was determined by single-crystal X-ray diffraction. The preliminary bioassy results indicated that some of them showed moderate inhibition activity against Colletotrichum orbiculare, Botrytis cinerea and Rhizoctonia solani.

Cheng-Xia Tan

2012-01-01

328

Synthesis and Antimicrobial Activity of Some New 2-(3-(4-Aryl)-1-phenyl-1H-pyrazol-4-yl) Chroman-4-ones  

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Seven new 2-(3-(4-aryl)-1-phenyl-1H-pyrazol-4-yl) chroman-4-ones (4a-4g) have been synthesized by cyclization of 2-hydroxychalcone analogues of pyrazole 3a-3g using conc. HCl in acetic acid. The structures of the compounds 4a-4g were established by the combined use of 1HNMR, IR and mass spectra. All the seven compounds were tested in vitro for their antibacterial activity against two Gram positive bacteria namely Staphylococcus aureus and Bacillus subtilis and two Gram negative bacteria Esche...

2011-01-01

329

Syntheses and biological evaluation of 1-heteroaryl-2-aryl-1H-benzimidazole derivatives as c-Jun N-terminal kinase inhibitors with neuroprotective effects.  

Science.gov (United States)

1-Heteroaryl-2-aryl-1H-benzimidazole derivatives were synthesized as inhibitors of c-Jun N-terminal kinases, JNK3. Their activities were evaluated through measurement of Kd using SPR, JNK3 kinase assay, and cell-viability of human neuroblastoma cells. Most tested compounds showed high affinity (10 ?M-46 nM) to JNK3. Among them, compound 16f exhibited potent activities (Kd=46 nM). Especially, 16f was also found to present a potent cell protective effect (IC50=1.09 ?M) against toxicity induced by anisomycin, showing a possibility as protective therapeutics in neuronal cell apoptosis. PMID:23498914

Kim, Mi-hyun; Lee, Junghun; Jung, Kyungjin; Kim, Minjung; Park, Yun-Jin; Ahn, Heechul; Kwon, Young Hye; Hah, Jung-Mi

2013-04-15

330

Preliminary evaluation of antimicrobial activity of diastereomeric cis/trans-3-aryl(heteroaryl)-3,4-dihydroisocoumarin-4-carboxylic acids.  

Science.gov (United States)

Preliminary differentiating screening of the antibacterial and antifungal activity of a series of diastereomeric cis/trans-3-aryl(heteroaryl)-3,4-dihydroisocoumarin-4-carboxylic acids (3a-i) was performed by the agar diffusion method against twelve microorganism strains of different taxonomic groups. S. aureus and A. niger were the most sensitive strains to the antibiotic effect of the tested compounds, both inhibited by 10 of 12 compounds. The most potent antibacterial agent was cis-3-phenyl-3,4-dihydroisocoumarin-4-carboxylic acid (cis-3a), exhibiting activity against all seven bacterial test strains. PMID:17913060

Bogdanov, Milen G; Kandinska, Meglena I; Dimitrova, Darina B; Gocheva, Blagovesta T; Palamareva, Mariana D

2007-01-01

331

Synthesis and antiproliferative evaluation of 13-aryl-13H-benzo[g]benzothiazolo [2,3-b]quinazoline-5,14-diones.  

Science.gov (United States)

A simple synthesis of novel 13-aryl-13H-benzo[g]benzothiazolo [2,3-b]quinazoline-5,14-dione derivatives was accomplished in excellent yields via the reaction of 2-aminobenzothiazole, aromatic aldehydes and 2-hydroxy-1,4-naphthoquinone in the presence of amberlyst-15. The antiproliferative activities of all the synthesized compounds were assessed on two different human cancer cell lines (HepG2 and Hela), and the results showed that most of the new compounds showed good to potent cytotoxic activities. PMID:24582982

Wu, Liqiang; Zhang, Chong; Li, Weilin

2014-03-15

332

Synthesis and pharmacological evaluation of novel N-aryl-3,4-dihydro-1'H-spiro[chromene-2,4'-piperidine]-1'-carboxamides as TRPM8 antagonists.  

Science.gov (United States)

A novel series of N-aryl-3,4-dihydro-1'H-spiro[chromene-2,4'-piperidine]-1'-carboxamides was identified as transient receptor potential melastatin 8 (TRPM8) channel blockers through analogue-based rational design, synthesis and screening. Details of the synthesis, effect of aryl groups and their substituents on in-vitro potency were studied. The effects of selected functional groups on the 4-position of the chromene ring were also studied, which showed interesting results. The 4-hydroxy derivatives showed excellent potency and selectivity. Optical resolution and screening of alcohols revealed that (R)-(-)-isomers were in general more potent than the corresponding (S)-(+)-isomers. The isomer (R)-(-)-10e (IC50: 8.9nM) showed a good pharmacokinetic profile upon oral dosing at 10mg/kg in Sprague-Dawley (SD) rats. The compound (R)-(-)-10e also showed excellent efficacy in relevant rodent models of neuropathic pain. PMID:24055075

Chaudhari, Sachin S; Kadam, Ashok B; Khairatkar-Joshi, Neelima; Mukhopadhyay, Indranil; Karnik, Pallavi V; Raghuram, Anupindi; Rao, Shobha S; Vaiyapuri, Thamil Selvan; Wale, Dinesh P; Bhosale, Vikram M; Gudi, Girish S; Sangana, Ramchandra R; Thomas, Abraham

2013-11-01

333

A quantitative structure-activity relationship study of novel inhibitors of cyclooxygenase-2: The 5-aryl-2,2-dialkyl-4-phenyl-3(2 Hfuranone derivatives  

Directory of Open Access Journals (Sweden)

Full Text Available The cyclooxygenase-2 enzyme inhibition activity of 5-aryl-2,2-dialkyl-4-phenyl-3(2 H furanone derivatives is quantitatively analyzed through Fujita-Ban and Hansch type of approaches. The analyses have helped to ascertain the role of different substituents in explaining the observed inhibitory activity of these congeners. From both approaches it is revealed that more hydrophobic susbtituents at 4- R1, a non-hydrogen bond acceptor substitutent, preferably a -F substituent, at 3- R1 in 4-phenyl ring of 3(2 H furanone scaffold improve inhibitory action of a compound. The substituents exhibiting collective molecular bulk smaller than spirocyclopentyl at X and Y positions are preferred as these geminal positions seems to be involved in steric interation. Similarly, 4-aminosulfonyl in 5-aryl ring of 3(2 H furanone moiety emerged as a better choice than 4-methylsulfonyl substitution.

Singh P

2007-01-01

334

ONE-POT SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF 2-AMINO-5-ARYL-5H-THIAZOLO [4,3-b]-1,3,4-THIADIAZOLES  

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Full Text Available A series of 2-amino-5-aryl-5H-thiazolo[4,3-b]-l,3,4-thiadiazoles were synthesized by using aromatic aldehydes, thioglycolic acid and thiosemicarbazide. Equimolar mixtures of aromatic aldehydes with thioglycolic acid and thiosemicarbazide in H2SO4 transform into 2-amino-5-aryl-5H-thiazolo[4,3-b]-l,3,4-thiadiazoles. Structures of all synthesized compounds were confirmed by FTIR, 1H NMR and mass spectral data. Fungicidal activity against two fungi Aspergillus niger and Candida albicans and bactericidal activity against two gram +ve bacteria Staphylococcus aureus, Escherichia fecalis and two gram ve bacteria Escheridhia coli, Klebsiella pneumonia and found to be active against these microorganisms.

Karigar Asif A.

2011-02-01

335

Nickel-Mediated Hydrogenolysis of C-O Bonds of Aryl Ethers: What Is the Source of the Hydrogen?  

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Mechanistic studies of the hydrogenolysis of aryl ethers by nickel were undertaken with (diphosphine)aryl methyl ethers. A Ni(0) complex containing Ni-arene interactions adjacent to the aryl-O bond was isolated. Heating led to aryl-O bond activation and generation of a nickel-aryl-methoxide complex. Formal ?-H elimination from this species produced a nickel-aryl-hydride which can undergo reductive elimination in the presence of formaldehyde to generate a carbon monoxide adduct of Ni(0). The ...

Kelley, Paul; Lin, Sibo; Edouard, Guy; Day, Michael W.; Agapie, Theodor

2012-01-01

336

Preparation and characterization of aryl-substituted polysilsesquioxanes  

Energy Technology Data Exchange (ETDEWEB)

Polymerizations of aryltrialkoxysilanes generally afford soluble oligomeric or polymeric aryl-substituted silsesquioxanes. This is in spite of being based on trifunctional precursors capable of forming highly crosslinked and insoluble network polymers. In this study, soluble phenyl, benzyl, and phenethyl-substituted silsesquioxane oligomers and polymers were prepared by hydrolyzing their respective triethoxysilyl precursor with water or aqueous acid. Additional samples of the polymers were prepared by heating the materials at 100 C or 200 C under vacuum in order to drive the condensation chemistry. One sample of polybenzylsilsesquioxane was heated at 200 C with catalytic NaOH. The resulting materials were characterized using solution {sup 1}H, {sup 13}C, and {sup 29}Si NMR spectroscopy, gel permeation chromatography, and differential scanning calorimetry. Of particular interest was the effect of the aryl substituent, and processing conditions on the molecular weight and glass transition temperatures of the polysilsesquioxanes.

Schneider, D.A.; Loy, D.A.; Baugher, B.M.; Wheeler, D.R.; Assink, R.A.; Alam, T.M.; Saunders, R.

1998-09-01

337

Suzuki-Miyaura Cross-Coupling Reactions of Primary Alkyltrifluoroborates with Aryl Chlorides  

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Parallel microscale experimentation was used to develop general conditions for the Suzuki-Miyaura cross-coupling of diversely functionalized primary alkyltrifluoroborates with a variety of aryl chlorides. These conditions were found to be amenable to coupling with aryl bromides, iodides, and triflates as well. The conditions that were previously identified through similar techniques to promote the cross-coupling of secondary alkyltrifluoroborates with aryl chlorides were not optimal for the p...

Dreher, Spencer D.; Lim, Siang-ee; Sandrock, Deidre L.; Molander, Gary A.

2009-01-01

338

Synthesis of tricyclic heterocycles via a tandem aryl alkylation/heck coupling sequence.  

Science.gov (United States)

A norbornene-mediated palladium-catalyzed sequence is described in which two alkyl-aryl bonds and one alkenyl-aryl bond are formed in one pot with use of microwave irradiation. A variety of symmetrical and unsymmetrical oxygen-, nitrogen-, silicon-, and sulfur-containing tricyclic heterocycles were synthesized from a Heck acceptor and an aryl iodide containing two tethered alkyl halides. This approach was further applied to the synthesis of a tricyclic mescaline analogue. PMID:17253794

Alberico, Dino; Rudolph, Alena; Lautens, Mark

2007-02-01

339

Palladium- (and nickel-) catalyzed vinylation of aryl halides  

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Functionalized styrenes are extremely useful building blocks for organic synthesis and for functional polymers. One of the most general syntheses of styrenes involves the combination of an aryl halide with a vinyl organometallic reagent under catalysis by palladium or nickel complexes. This Feature Article provides the first comprehensive summary of the vinylation methods currently available along with a critical comparison of the efficiency, cost and scope of the methods.

Denmark, Scott E.; Butler, Christopher R.

2009-01-01

340

NRF2 Modulates Aryl Hydrocarbon Receptor Signaling: Influence on Adipogenesis?  

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The NF-E2 p45-related factor 2 (NRF2) and the aryl hydrocarbon receptor (AHR) are transcription factors controlling pathways modulating xenobiotic metabolism. AHR has recently been shown to affect Nrf2 expression. Conversely, this study demonstrates that NRF2 regulates expression of Ahr and subsequently modulates several downstream events of the AHR signaling cascade, including (i) transcriptional control of the xenobiotic metabolism genes Cyp1a1 and Cyp1b1 and (ii) inhibition of adipogenesis...

Shin, Soona; Wakabayashi, Nobunao; Misra, Vikas; Biswal, Shyam; Lee, Gum Hwa; Agoston, Elin S.; Yamamoto, Masayuki; Kensler, Thomas W.

2007-01-01

 
 
 
 
341

Two anionic [CuI6X7]nn- (X=Br and I) chain-based organic-inorganic hybrid solids with N-substituted benzotriazole ligands  

International Nuclear Information System (INIS)

Solvothermal reactions of the flexible ligand 1,6-Bi(benzotriazole)hexane with CuI and KI or CuBr and KBr in ethanol generate two hybrid compounds, namely, {(HETA)[(Cu6I7)(ETA)2]}n(1) and {K(Cu6Br7)(BBTH)}n(2) (ETA=N-ethylbenzotriazole, HETA=protonated N-ethylbenzotriazole, BBTH=1,6-bi(benzotriazole)hexane). In 1, two [Cu3I4] vertex missing cubane-like subunits link each other by sharing one I atom to give a [Cu6I7] cluster, which further form novel 1D [Cu6I7]nn- anionic chain. Two in-situ generated ETA ligands finished the 4-coordinated environments of copper centers and another one discrete protonated ETA ligand keeps the charge neutrality for 1. In complex 2, bowl-shaped [Cu5Br4] clusters and rhomboid [Cu2Br2] dimers link each other to generate a [Cu6Br7]nn- 1D chain. BBTH ligands complete the tetrahedral spheres of Cu(I), and 7-coordinated K atoms further extend the 1D chain motifs to a 2D hybrid layer of 2. The UV-vis diffuse reflectance spectrum and luminescence measurements show that compound 1 and 2 both are potential semiconductor and photoluminescence materials. - Graphical abstract: Two unprecedented anionic [CuI6X7]nn- (X=Br and I) chain-based organic-inorganic hybrid solids, namely, {(HETA)[(Cu6I7)(ETA)2]}n (1) and {K(Cu6Br7)(BBTH)}n(2) (ETA=N-ethylbenzotriazole, HETA=protonated N-ethylbenzotriazole, BBTH=1,6-bi(benzotriazole)- hexane) have been synthesized under solvothermal reactions and characterized.

2010-05-01

342

Synthesis and cross-coupling reactions of imidomethyltrifluoroborates with aryl chlorides  

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Potassium imidomethyltrifluoroborate salts were efficiently synthesized. Potassium phthalimidomethyl-trifluoroborate was successfully used in SuzukiMiyaura-like cross-coupling reactions with a variety of aryl chlorides.

Devulapally, Rammohan; Fleury-bre?geot, Nicolas; Molander, Gary A.; Seapy, Dave G.

2012-01-01

343

Quantum mechanistic insights on aryl propargyl ether Claisen rearrangement.  

Science.gov (United States)

The mechanism of aryl propargyl ether Claisen rearrangement in gas and solvent phase was investigated using DFT methods. Solvent phase calculations are carried out using N,N-diethylaniline as a solvent in the PCM model. The most favorable pathways involve a [3,3]-sigmatropic reaction followed by proton transfer in the first two steps and then deprotonation or [1,5]-sigmatropic reaction. Finally, cyclization yields benzopyran or benzofuran derivatives. The [3,3]-sigmatropic reaction is the rate-determining step for benzopyran and benzofuran with ?G() value of 38.4 and 37.9 kcal mol(-1) at M06/6-31+G**//B3LYP/6-31+G* level in gas and solvent phase, respectively. The computed results are in good agreement with the experimental results. Moreover, it is found that the derivatives of aryl propargyl ether proceeded Claisen rearrangement and the rate-determining step may be shifted from the [3,3]-sigmatropic reaction to the tautomerization step. The NBO analysis revealed that substitution of the methyl groups on the aliphatic segment has decreased the stabilization energy E(2) and favors the aryl propargyl ether Claisen rearrangement. PMID:24827936

Srinivasadesikan, Venkatesan; Dai, Jiun-Kuang; Lee, Shyi-Long

2014-06-28

344

Group IB Organometallic Chemistry XXXIII: ArAuPPh3, ArAu(CNR), (ArAu)n and Ar4Cu2Au2 compounds in which the aryl group contains 2-MeO, 2,6-(MeO)2, 2-Me2N, 2-Me2NCH2 and (S)- or (R)-2-Me2NCHMe substituents as potential ligands  

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The synthesis and structural characterization by }1{H NMR and }1{}9{}7{Au Mossbauer spectroscopy as well as by chiral labelling of the built-in ligands of three different types of arylgold(I) compounds is described.}1{}9{}7{Au Mossbauer data revealed that the benzyl- and arylgold(I) triphenylphosphine complexes which bear potential coordinating substituents at an ortho position still contain linearly coordinated Au}I{ with 2c-2e gold(I)@?carbon bonds. The observation of isochronous NME resona...

Koten, G.; Schaap, C. A.; Jastrzebski, J. T. B. H.; Noltes, J. G.

1980-01-01

345

In vitro evaluation of anti-pathogenic surface coating nanofluid, obtained by combining Fe3O4/C12 nanostructures and 2-((4-ethylphenoxy)methyl)- N-(substituted-phenylcarbamothioyl)-benzamides  

Science.gov (United States)

In this paper, we report the design of a new nanofluid for anti-pathogenic surface coating. For this purpose, new 2-((4-ethylphenoxy)methyl)- N-(substituted-phenylcarbamothioyl)-benzamides were synthesized and used as an adsorption shell for Fe3O4/C12 core/shell nanosized material. The functionalized specimens were tested by in vitro assays for their anti-biofilm properties and biocompatibility. The optimized catheter sections showed an improved resistance to Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 in vitro biofilm development, as demonstrated by the viable cell counts of biofilm-embedded bacterial cells and by scanning electron microscopy examination of the colonized surfaces. The nanofluid proved to be not cytotoxic and did not influence the eukaryotic cell cycle. These results could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with improved anti-biofilm properties.

Anghel, Ion; Limban, Carmen; Grumezescu, Alexandru Mihai; Anghel, Alina Georgiana; Bleotu, Coralia; Chifiriuc, Mariana Carmen

2012-09-01

346

Synthesis and antibacterial activity of 2-(2,4-dinitrophenyl-3,5-diphenyl (substituted-6-aryl-3,3a,5,6-tetrahydro-2H-pyrazolo[3,4-d] thiazoles  

Directory of Open Access Journals (Sweden)

Full Text Available Condensation of substituted benzaldehydes with primary aryl amines gave a series of Schiff bases(1a 1 -e 1 ,a 2 ,b 2 ,d 2 ,b 3 -e 3 which, on reaction with thioglycolic acid, resulted in the formation of the corresponding 4-thiazolidinones(2a 1 -e 1 ,a 2 ,b 2 ,d 2 ,b 3 -e 3 . These compounds, on condensation with substituted benzaldehydes in anhydrous sodium acetate, furnished 2-phenyl(substituted-3-aryl-5-benzilidine(substituted-thiazolidine-4-ones(3a 1 -e 1 ,a 2 ,b 2 ,d 2 , b 3 -e 3 . The latter, on heating with 2,4-dinitrophenyl hydrazine in anhydrous sodium acetate, gave the title compounds(4a 1 -e 1 ,a 2 ,b 2 ,d 2 ,b 3 -e 3 . The structures have been established on the basis of elemental analysis and spectral data. The title compounds have been screened in vitro for their possible antibacterial activity

Sahu S

2006-01-01

347

Computational Study on the Acid Catalyzed Reactions of Fluorine-Containing 2,4-Dialkoxy-3,4-dihydro-2H-pyrans with Aromatic Compounds  

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The reaction of 2,4-diethoxy-6-trifluoromethyl-3,4-dihydro-2H-pyran (1) with aromatic compounds in refluxing acetonitrile in the presence of p-toluenesulfonic acid gave the mixture of 4-aryl-2-trifluoromethyl-4H-pyrans (3) and 6-aryl-1,1,1-trifluorohexa-3,5-dien-2-ones (4). In contrast, the same reaction carried out in trifluoroacetic acid at ambient temperature afforded 4-aryl-2-ethoxy-6-trifluoromethyl-3,4-dihydro-2H-pyrans (2) selectively. These two types of reactions giving quite differen...

Norio Ota; Yasuhiro Kamitori; Ryusuke Shirai; Mizuki Hatakenaka; Etsuji Okada

2012-01-01

348

4-Aryl-4H-Naphthopyrans Derivatives: One-pot Synthesis, Evaluation of Src Kinase Inhibitory and Anti-proliferative Activities  

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Full Text Available The one-pot, three-component reaction of ? or ?-naphthol, malonitrile and an aromatic aldehyde in the presence of Diammonium hydrogen phosphate was afforded the corresponding 2-amino-4-aryl-4H-benzo[h or f]chromene-3-carbonitrile derivatives, All target compounds were evaluated for inhibition of Src kinase and cell proliferation in breast carcinoma (BT-20 cell lines.Results Among all tested compounds, unsubstituted 4-phenyl analog 4a showed Src kinas inhibitory effect with IC50 value of 28.1 ?M and was the most potent compound in this series. Ingeneral, the compounds were moderately active against BT-20. 3-Nitro-phenyl 4e and 3- pyridinyl 4h derivatives inhibited the cell proliferation of BT-20 cells by 33% and 31.5%,respectively, and found to be more potent compared to doxorubicin (25% inhibition of cell growth. ConclusionThe data indicate that 4-aryl-4H-naphthopyrans scaffold has the potential to be optimized further for designing more potent Src kinase inhibitors and/or anticancer lead compounds.

Ali Rafinejad

2012-01-01

349

TBAHS CATALYZED COUPLING REACTIONS OF ARYL IODIDES AND ARYL BROMIDES WITH THIOLS UNDER SOLVENT FREE CONDITIONS TBAHS katalysierten Kupplungen von Aryliodiden und-Arylbromiden mit Thiolen unter lsungsmittelfreien freien Bedingungen  

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Full Text Available A recyclable and efficient Tetrabutylammonium hydrogensulfate (TBAHS catalysed coupling reaction of aryl halides (iodide and bromide with aryl and alkyl thiols under solvent-free conditions were developed.

Gajendera Singha, Ajay kumarb , Sakshi Malikc, Preeti Chaudharyd

2013-04-01

350

An Ef?cient Synthesis of 1-Aryl-3-(indole-3-yl-3-(2-aryl-1,2,3-triazol-4-ylpropan-1-one Catalyzed by a Brnsted Acid Ionic Liquid  

Directory of Open Access Journals (Sweden)

Full Text Available An efficient synthesis of novel 1-aryl-3-(indole-3-yl-3-(2-aryl-1,2,3-triazol-4-ylpropan-1-ones from indoles and 1-aryl-3-(2-aryl-1,2,3-triazol-4-ylpropan-1-one using a Brnsted acid ionic liquid [Sbmim][HSO4] as catalyst is described. Satisfactory results with excellent yields and short reaction time were obtained in the experiments. The catalyst could be recovered conveniently and reused efficiently.

Chuan-Ji Yu

2010-12-01

351

Preparation and assessment of [99mTc]technetium aquacarbonyl complexes with 1,2-diaminoethane-N-substituted ligands for tumor detection  

International Nuclear Information System (INIS)

Over least 15 years the complex [[99mTc](H20)3(CO)3]+ has been used as an intermediary to obtain technetium radiopharmaceuticals for applications in cardiology, neurology and oncology. Two important characteristics of this molecule are: the facility for obtaining that compound from aqueous solutions and the easiness of substituting H2O molecules by atoms of other ligand molecules. In this project we prepared new complexes [[99mTc](CMNS001-3)(H2O)(CO)3]+, where (CMNS001) = N-[(4-methoxy) benzyl]-1,2-diaminoethane, (CMNS003) = N,N'-bis-[(4-methoxy)benzyl]-1,2-diaminoethane, and assessed the uptake of these complexes in murine melanoma cancer cell B16F10 and breast cells MCF-7 and MDA-MD-231, and compared with [[99m](MIBI)6]+ uptake. In vitro uptake for both new technetium complex reached values close to 5%, for all cell lines, whereas the [[99mTc](MIBI)6]+ uptake was close to 1 %. The assessment of subcellular distribution showed high accumulation of the new complex in the membrane fraction, for MDAMB-231, while for B16F10 accumulation occurred both in membrane and cytoplasm; the concentration of [[99mTc](MIBI)6]+ was mainly in the cytoplasm portion. Biodistribution study in mice allowed to observe the capture of up to 1.6% of the administered dose per gram of tumor tissue for the complex [[99mTc](CMNS001)(H2O)(CO)3]+, whereas other organs such as heart, lung and muscle, showed uptake of about 5.6%, 6.4% and 2%, respectively. The complexes in this work showed a high rate of uptake in vitro, but was not reproduced in vivo model, which can be related to low concentration of the complexes inside the cells and reduced vascularity of tumor tissue, with lower intake of complex through the blood system. (author)

2010-01-01

352

Aryl phosphate derivatives of bromo-methoxy-azidothymidine are dual-function spermicides with potent anti-human immunodeficiency virus.  

Science.gov (United States)

Detergent-based vaginal microbicides, in addition to their high contraceptive failure rates, cause mucosal erosion and local inflammation that might increase the risk of heterosexual human immunodeficiency virus (HIV) transmission. In a systematic effort to identify a microbicide contraceptive potentially capable of preventing the sexual transmission of HIV as well as providing fertility control, a series of novel aryl phosphate derivatives of 5-bromo-6-methoxy-3'-azido-3'-deoxythymidine (AZT; zidovudine) were synthesized and examined for dual anti-HIV and sperm-immobilizing activity (SIA). Whereas AZT displayed potent anti-HIV activity (IC50 = 0.006 microM) but lacked SIA (EC50 > 300 microM), two 5-bromo-6-methoxy-aryl phosphate derivatives of AZT, compounds WHI-05 and WHI-07, exhibited potent anti-HIV activity as well as SIA. The IC50 (HIV) and EC50 (SIA) values for WHI-07 were 439-fold and 13.5-fold lower, respectively, than those for the detergent-based virucidal spermicide, nonoxynol-9 (N-9). Sperm motion kinematics using computer-assisted sperm motion analysis combined with confocal laser scanning microscopy, high-resolution low-voltage scanning, and transmission electron microscopy demonstrated that both WHI-05 and WHI-07 cause a complete and irreversible loss of sperm motility in a concentration- and time-dependent fashion without concomitantly affecting the sperm acrosomal membrane integrity. In experiments designed to assess the fertilizing capacity of treated sperm, preincubation of sperm with either compound resulted in a concentration-dependent loss of the ability to adhere to and penetrate zona-free hamster eggs as well as inhibition of binding to human zona. WHI-07 applied intravaginally prior to artificial insemination of epididymal sperm drastically reduced fertility in hormonally primed CD-1 mice. Unlike the intravaginal application of N-9, repetitive intravaginal application of WHI-07 did not damage the vaginal epithelium or cause local inflammation. Structure-function relationship analyses showed that the addition of bromo-methoxy functional groups to AZT was essential for, and the aryl phosphate derivatization contributory to, the SIA of both compounds. Compounds WHI-05 and WHI-07 may be useful as dual-function vaginal contraceptives for women who are at high risk for acquiring HIV/acquired immunodeficiency virus syndrome by heterosexual vaginal transmission. PMID:9716547

D'Cruz, O J; Venkatachalam, T K; Zhu, Z; Shih, M J; Uckun, F M

1998-09-01

353

Development of the polyurethane sponge as a delivery system for aryl 4-guanidinobenzoates.  

Science.gov (United States)

The Today Contraceptive Sponge was evaluated as a vehicle for the delivery of aryl 4-guanidinobenzoates (AGs) which are highly active sperm acrosin inhibitors. Studies in animals have shown that several AGs are more potent vaginal contraceptives and less irritating to the vagina than nonoxynol-9 (N-9), the most frequently used active ingredient in commercial vaginal contraceptive formulations. Neither nonoxynol-9 nor the material that could be solubilized from the sponge matrix altered the enzyme-inhibitory activity of 4'-acetamidophenyl 4-guanidinobenzoate HCl (AGB), 4'-carboxyphenyl 4-guanidinobenzoate HCl (EGB) or 4'-carbomethoxyphenyl 4-guanidinobenzoate HCl (MSGB). Besides being acrosin inhibitors, all three AGs exhibited antimotility activity towards human spermatozoa, EGB being as potent as N-9. The antimotility effects of the AGs and N-9 were additive. For subsequent studies, AGB was used as the model compound. Manufacture of the AGB-containing sponges did not affect the chemical structure of AGB. Good release rates of AGB were obtained from the sponges over a 7-day period. The release rates were 20-50% higher when the sponges also contained N-9. These results indicate that certain AGs exert a dual contraceptive action on spermatozoa by inhibiting both the sperm enzyme acrosin and sperm motility. Furthermore, the polyurethane sponge appears to be a convenient and satisfactory long-term delivery system for the AGs. A mixture of N-9 and AG can be used clinically because these compounds have no adverse effects on each other. PMID:2850136

Quigg, J M; Miller, I F; Mack, S R; Saxena, S J; Kaminski, J M; Zaneveld, L J

1988-10-01

354

Anthocyans fail to suppress transformation of aryl hydrocarbon receptor induced by dioxin.  

Science.gov (United States)

Dioxins induce adverse effects through transformation of the cytosolic aryl hydrocarbon receptor (AhR). Our previous study found that flavones and flavonols at dietary levels suppress AhR transformation. In the present study, we investigated whether 20 anthocyans dissolved in trifluoroacetic acid (TFA)-MeOH suppressed AhR transformation in a cell-free system and in Hepa-1c1c7 cells. Although four compounds at 50 muM suppressed 0.1 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced AhR transformation and their effects were dose-dependent in the cell-free system, they were ineffective at 0.5 muM, which is close to physiological concentration. Moreover, no anthocyan at 50 muM tested here suppressed 0.1 nM TCDD-induced AhR transformation in Hepa-1c1c7 cells. We also confirmed that protocatechuic acid and related compounds, which are possible metabolites of anthocyans, did not affect the transformation in the cell-free system. It is concluded that anthocyans are not suitable candidates for protection from dioxin toxicity. PMID:15914907

Mukai, Rie; Fukuda, Itsuko; Hosokawa, Keizo; Nishiumi, Shin; Kaneko, Atsushi; Ashida, Hitoshi

2005-05-01

355

MICROWAVE ASSISTED SYNTHESIS OF 6-BENZOYL-5-METHYL-2-[(Z-1-ARYL METHYLIDENE]-2,3-DIHYDROFURO [3,2 :4,5] BENZO[b] FURAN-3-ONES AND THEIR ANTIBACTERIAL ACTIVITY Mikrowellen untersttzte Synthese von 6-Benzoyl-5-METHYL-2-[(Z-1-ARYL Methyliden] -2,3-DIHYDROFURO [3", 2": 4,5] benzo [b] furan-3-one und Ihre antibakterielle Aktivitt  

Directory of Open Access Journals (Sweden)

Full Text Available A series of 6-Benzoyl-5-methyl-2-[(Z-1-arylmethylidene]-2,3-dihydrofuro[3,2:4,5] benzo[b]furan-3-ones have been prepared by an efficient oxidation of (E-1-(2-Benzoyl- 6-hydroxy-3-methyl benzo[b] furan-5-yl-3-aryl-2-propen-1-ones with cupric bromide or mercuric acetate under microwave irradiation. The structures of newly synthesized compounds have been established on the basis of elemental analysis, IR, 1H-NMR,13 C-NMR and mass spectral data. All the compounds were screened for their antibacterial activity.

Ashok D, Sudershan K and Khalilullah M

2011-10-01

356

Base-promoted aryl-bromine bond cleavage with cobalt(ii) porphyrins via a halogen atom transfer mechanism.  

Science.gov (United States)

Aryl-bromine bonds are successfully cleaved by cobalt(ii) porphyrins in basic media to give Co(por)Ar (por = porphyrin) in good yields. Mechanistic studies suggested that the aryl-bromine bond is cleaved through a halogen atom transfer mechanism, which is different from the aryl-halogen bond cleavage mechanism with other group 9 metalloporphyrins. PMID:24699823

Liu, Chun Ran; Qian, Ying Ying; Chan, Kin Shing

2014-06-01

357

Stereoselective copper-catalyzed Chan-Lam-Evans N-arylation of glucosamines with arylboronic acids at room temperature.  

Science.gov (United States)

An efficient and practical N-arylation of glycosylamines with substituted aryl boronic acids has been established. Using Cu(OAc)2 and pyridine at room temperature under air atmosphere, the protocol proved to be general, and a variety of aryl N-glycosides have been prepared in good to excellent yields with exclusive ? selectivity. PMID:23928939

Bruneau, Alexandre; Brion, Jean-Daniel; Alami, Mouad; Messaoudi, Samir

2013-09-28

358

Cinchona alkaloids/TMAF combination-catalyzed nucleophilic enantioselective trifluoromethylation of aryl ketones.  

Science.gov (United States)

The catalytic, nucleophilic enantioselective trifluoromethylation reaction of both acyclic and cyclic aryl ketones using the Ruppert-Prakash reagent is now at hand, with an operationally simple procedure, based on the combination of ammonium bromide of cinchona alkaloids with TMAF. The procedure is reliable and general. Trifluoromethyl-substituted tetrasubstituted aryl alcohols have been synthesized in up to 94% ee. PMID:17691734

Mizuta, Satoshi; Shibata, Norio; Akiti, Surendar; Fujimoto, Hiroyuki; Nakamura, Shuichi; Toru, Takeshi

2007-08-30

359

Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester  

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An aryl substrate with dual functionality consisting of a nitrile oxide and a pinacolyl boronate ester was prepared by mild hypervalent iodine oxidation (diacetoxyiodobenzene) of the corresponding aldoxime, without decomposition of the boronate functionality. The nitrile oxide was trapped in situ with a variety of dipolarophiles to yield aryl isoxazolines with the boronate ester function intact and available for subsequent reaction.

2012-01-01

360

Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester  

Directory of Open Access Journals (Sweden)

Full Text Available An aryl substrate with dual functionality consisting of a nitrile oxide and a pinacolyl boronate ester was prepared by mild hypervalent iodine oxidation (diacetoxyiodobenzene of the corresponding aldoxime, without decomposition of the boronate functionality. The nitrile oxide was trapped in situ with a variety of dipolarophiles to yield aryl isoxazolines with the boronate ester function intact and available for subsequent reaction.

Sarah L. Harding

2012-04-01

 
 
 
 
361

Cu-Catalyzed Arylation of Phenols: Synthesis of Sterically Hindered and Heteroaryl Diaryl Ethers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cu-catalyzed O-arylation of phenols with aryl iodides and bromides can be performed under mild condition in DMSO/K3PO4 with use of picolinic acid as the ligand for copper. This method tolerates a variety of functional groups and is effective in the synthesis of hindered diaryl ethers and heteroaryl ethers.

Maiti, Debabrata; Buchwald, Stephen Leffler

2009-01-01

362

Rh(III)-catalyzed oxidative coupling of N-aryl-2-aminopyridine with alkynes and alkenes.  

Science.gov (United States)

[RhCp*Cl(2)](2) (1-2 mol %) can catalyze the oxidative coupling of N-aryl-2-aminopyridines with alkynes and arylates to give N-(2-pyridyl)indoles and N-(2-pyridyl)quinolones, respectively, using Cu(OAc)(2) as an oxidant. Coupling with styrenes gave mono- and/or disubstituted olefination products. PMID:21038875

Chen, Jinlei; Song, Guoyong; Pan, Cheng-Ling; Li, Xingwei

2010-12-01

363

Base-Mediated Intermolecular sp2 C-H Bond Arylation via Benzyne Intermediates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A transition-metal-free method for arylation of heterocycle and arene carbon-hydrogen bonds by aryl chlorides and fluorides has been developed. The reactions proceed via aryne intermediates and are highly regioselective with respect to the C-H bond coupling component.

Truong, Thanh; Daugulis, Olafs

2011-01-01

364

Copper-catalyzed free-radical C-H arylation of pyrroles.  

Science.gov (United States)

A room temperature copper-catalyzed radical arylation of pyrroles with anilines, through in situ generated aryl diazonium salts, has been developed under neutral conditions. Experimental and theoretical studies explain the crucial role of CaCO3 and the high regioselectivity observed. PMID:23970307

Honraedt, Aurlien; Raux, Marie-Audrey; Grognec, Erwan Le; Jacquemin, Denis; Felpin, Franois-Xavier

2014-05-25

365

Gorlos-Phos for palladium-catalyzed borylation of aryl chlorides.  

Science.gov (United States)

Using a readily available form of the mono-phosphine ligand, Gorlos-PhosHBF4, Pd-catalyzed borylation of aryl chlorides afforded aryl boronates in high yields. A variety of functional groups are well compatible with this palladium catalyzed borylation reaction. PMID:24781499

Li, Pengbin; Fu, Chunling; Ma, Shengming

2014-06-14

366

Inactivation of myoglobin by ortho-substituted arylhydrazines. Formation of prosthetic heme aryl-iron but not N-aryl adducts  

Energy Technology Data Exchange (ETDEWEB)

Stable phenyl-iron complexes are known to form in the reactions of myoglobin, hemoglobin, and catalase with phenylhydrazine. The phenyl moiety in these complexes migrates from the iron to a nitrogen of the porphyrin upon denaturation of the hemoproteins. Complexes obtained from myoglobin and ortho-substituted phenylhydrazines, however, are much less stable, have distinct chromophores, and do not yield N-arylporphyrins. These abnormal properties imply that the complexes differ in structure (e.g., they are aryldiazenyl-rather than aryl-iron complexes) or that ortho substitution strongly alters the chemistry of aryl-iron complexes. The present NMR studies unambiguously demonstrate that ortho-substituted phenylhydrazines give normal aryl-iron complexes but that the aryl group in these complexes is conformationally locked and is unable to shift from iron to nitrogen.

Ortiz de Montellano, P.R.; Kerr, D.E.

1985-02-26

367

Diaryl sulfoxides from aryl benzyl sulfoxides: a single palladium-catalyzed triple relay process.  

Science.gov (United States)

A novel approach to produce diaryl sulfoxides from aryl benzyl sulfoxides is reported. Optimization of the reaction conditions was performed using high-throughput experimentation techniques. The [Pd(dba)2 ]/NiXantPhos catalyst system successfully promotes a triple relay process involving sulfoxide ?-arylation, C?S bond cleavage, and C?S bond formation. The byproduct benzophenone is formed by an additional palladium-catalyzed process. It is noteworthy that palladium-catalyzed benzylative C?S bond cleavage of sulfoxides is unprecedented. A wide range of aryl benzyl sulfoxides, as well as alkyl benzyl sulfoxides with various (hetero)aryl bromides were employed in the triple relay process in good to excellent yields (85-99?%). Moreover, aryl methyl sulfoxides, dibenzyl sulfoxides, and dimethylsulfoxide could be utilized to generate diaryl sulfoxides involving multiple catalytic cycles by a single catalyst. PMID:24273189

Jia, Tiezheng; Bellomo, Ana; Montel, Sonia; Zhang, Mengnan; El Baina, Kawtar; Zheng, Bing; Walsh, Patrick J

2014-01-01

368

Oxidative addition of aryl chlorides to monoligated palladium(0): A DFT-SCRF study  

DEFF Research Database (Denmark)

Oxidative addition of aryl chlorides to palladium has been investigated by hybrid density functional theory methods (B3LYP), including a continuum model describing the solvent implicitly. A series of para-substituted aryl chlorides were studied to see the influence of electronic effects on the reaction. It was found that the experimentally observed higher reactivity of the more electron deficient aryl chlorides is due to their ability to accept back-donation from Pd-0 and form reasonably strong pre-reactive complexes. This effect is less pronounced in the transition state; when it is measured from the pre-reactive complex, the barrier to oxidative addition is actually higher for the electron-deficient aryl chlorides, but the overall reaction barrier is still lower than for the electron-rich aryl chlorides.

Ahlquist, Mårten Sten Gösta; Norrby, Per-Ola

2007-01-01

369

Oxazolidinones as novel human CCR8 antagonists.  

Science.gov (United States)

High-throughput screening of the corporate compound collection led to the discovery of a novel series of N-substituted-5-aryl-oxazolidinones as potent human CCR8 antagonists. The synthesis, structure-activity relationships, and optimization of the series that led to the identification of SB-649701 (1a), are described. PMID:17267215

Jin, Jian; Wang, Yonghui; Wang, Feng; Kerns, Jeffery K; Vinader, Victoria M; Hancock, Ashley P; Lindon, Matthew J; Stevenson, Graeme I; Morrow, Dwight M; Rao, Parvathi; Nguyen, Cuc; Barrett, Victoria J; Browning, Chris; Hartmann, Guido; Andrew, David P; Sarau, Henry M; Foley, James J; Jurewicz, Anthony J; Fornwald, James A; Harker, Andy J; Moore, Michael L; Rivero, Ralph A; Belmonte, Kristen E; Connor, Helen E

2007-03-15

370

Synthesis, antiproliferative and anti-inflammatory activities of some novel 6-aryl-2-(p-(methanesulfonyl)phenyl)-4,5-dihydropyridazi-3(2H)-ones.  

Science.gov (United States)

Sixteen new 6-aryl-2-(p-(methanesulfonyl)phenyl)-4,5-dihydropyridazi-3(2H)-ones (2a-p) were synthesized and tested for in vitro anticancer and in vivo anti-inflammatory activities. Eleven (2b, 2d, 2e-j and 2m-p) of the obtained compounds were screened for their antiproliferative activity towards 60 human cancer cell lines by the National Cancer Institute (USA). Compound 2f showed remarkable activity with GI50 less than 1?M on 36 human tumor cell lines and has been referred to Biological Evaluation Committee (NCI) for advance study. Compound 2g also displayed promising antiproliferative activity against 20 different cell lines with GI50 less than 1?M. Compounds 2k and 2n were found to have a comparable anti-inflammatory activity to that of standard drug etoricoxib in carrageenan-induced rat hind paw edema model at 5h. PMID:23887055

Ovais, Syed; Javed, Kalim; Yaseen, Shafiya; Bashir, Rafia; Rathore, Pooja; Yaseen, Raed; Hameed, Alhamzah D; Samim, Mohammad

2013-09-01

371

Copper-catalyzed asymmetric hydrogenation of aryl and heteroaryl ketones.  

Science.gov (United States)

High throughput screening enabled the development of a Cu-based catalyst system for the asymmetric hydrogenation of prochiral aryl and heteroaryl ketones that operates at H2 pressures as low as 5 bar. A ligand combination of (R,S)-N-Me-3,5-xylyl-BoPhoz and tris(3,5-xylyl)phosphine provided benzylic alcohols in good yields and enantioselectivities. The electronic and steric characteristics of the ancillary triarylphosphine were important in determining both reactivity and selectivity. PMID:23980941

Krabbe, Scott W; Hatcher, Mark A; Bowman, Roy K; Mitchell, Mark B; McClure, Michael S; Johnson, Jeffrey S

2013-09-01

372

Unsymmetrical diaryl sulfones and aryl vinyl sulfones through palladium-catalyzed coupling of aryl and vinyl halides or triflates with sulfinic acid salts.  

Science.gov (United States)

The palladium-catalyzed reaction of sulfinic acid salts with a wide variety of aryl and vinyl halides or triflates provides unsymmetrical diaryl sulfones and aryl vinyl sulfones in good to excellent yields. The reaction is strongly influenced by the presence of nBu4NCl, and the use of Xantphos, a rigid bidentate ligand with a wide natural bite angle, was found to be crucial for the success of the reaction. With neutral, electron-rich, and electron-poor aryl iodides best results were obtained by using Pd2(dba)3, Xantphos, Cs2CO3, and nBu4NCl, in toluene at 80 degrees C. Two general procedures were employed with aryl bromides and triflates: sodium p-toluenesulfinate, Pd2(dba)3, Xantphos, Cs2CO3, 120 degrees C, in toluene with nBu4NCl (procedure A: neutral, electron-rich, and slightly electron-poor aryl bromides or triflates) and without nBu4NCl (procedure B: electron-poor aryl bromides or triflates). With vinyl triflates best results were obtained at 60 degrees C omitting nBu4NCl. PMID:15307729

Cacchi, Sandro; Fabrizi, Giancarlo; Goggiamani, Antonella; Parisi, Luca M; Bernini, Roberta

2004-08-20

373

Practical synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides via conventional and decarboxylative copper-free Sonogashira coupling reactions.  

Science.gov (United States)

Two efficient protocols for the palladium-catalyzed synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides in the absence of copper were developed. A simple catalytic system consisting of Pd(OAc)2 and P(p-tol)3 using DBU as the base and THF as the solvent was found to be highly effective for the coupling reaction of 2-methyl-3-butyn-2-ol (4) with a wide range of aryl bromides in good to excellent yields. Analogously, the synthesis of aryl-2-methyl-3-butyn-2-ols was performed also through the decarboxylative coupling reaction of 4-hydroxy-4-methyl-2-pentynoic acid with aryl bromides, using a catalyst containing Pd(OAc)2 in combination with SPhos or XPhos in the presence of tetra-n-butylammonium fluoride (TBAF) as the base and THF as the solvent. Therefore, new efficient approaches to the synthesis of terminal acetylenes from widely available aryl bromides rather than expensive iodides and using 4 or propiolic acid rather than TMS-acetylene as inexpensive alkyne sources are described. PMID:24605159

Caporale, Andrea; Tartaggia, Stefano; Castellin, Andrea; De Lucchi, Ottorino

2014-01-01

374

The synthesis, characterization and optical properties of novel 5-(3-aryl-1H-pyrazol-5-yl)-2-(3-butyl-1-chloroimidazo[1,5-a]pyridin-7-yl)-1,3,4-oxadiazole.  

Science.gov (United States)

A series of novel 5-(3-aryl-1H-pyrazol-5-yl)-2-(3-butyl-1-chloroimidazo[1,5-a]- pyridin-7-yl)-1,3,4-oxadiazole derivatives has been synthesized from 3-butyl-1-chloroimidazo[1,5-a]pyridine-7-carboxylic acid and ethyl 3-aryl-1H-pyrazole-5-carboxylate. The compounds were characterized using IR, (1)H NMR, HRMS and UV-vis absorption. The fluorescence spectral characteristics of the compounds in dichloromethane were investigated. The results showed that absorption ?max and emission ?max was less correlated with substituent groups on N-1 position of pyrazole moiety and para position of benzene moiety. The calculated molecular orbital correlates well with their absorption. PMID:24412786

Ge, Yan Qing; Jia, Jiong; Wang, Teng; Sun, Hong Wei; Duan, Gui Yun; Wang, Jian Wu

2014-04-01

375

Mechanistic Study of the Acid Degradation of Lignin Model Compounds  

Energy Technology Data Exchange (ETDEWEB)

Lignin is a major constituent of biomass, which remains underutilized in selective biomass conversion strategies to renewable fuels and chemicals. Here we are interested in understanding the mechanisms related to the acid deconstruction of lignin with a combined theoretical and experimental approach. Two model dimers with a b-O-4 aryl ether linkage (2-phenoxy-1-phenethanol and 2-phenoxy-1-phenyl-1,3 propanediol) and model dimmers with an a-O-4 aryl ether linkage were synthesized and deconstructed in H2SO4. The major products of the acidolysis of the b-O-4 compounds consisted of phenol and two aldehydes, phenylacetaldehyde and benzaldehyde. Quantum mechanical calculations were employed to elucidate possible deconstruction mechanisms with transition state theory. To confirm proposed mechanisms several possible intermediates were studied under similar acidolysis conditions. Although the resonance time for cleavage was on the order several hours, we have shown that the cleavage of the aryl ether linkage affords phenol and aldehydes. We would next like to utilize our mechanism of aryl ether cleavage in actual lignin.

Sturgeon, M.; Kim, S.; Chmely, S. C.; Foust, T. D.; Beckham, G. T.

2012-01-01

376

Synthesis and Biological Activity of 3-(2-Furanyl)-6-Aryl-1,2,4-Triazolo[3,4-b]-1,3,4 –Thiadiazoles  

Digital Repository Infrastructure Vision for European Research (DRIVER)

3-(2-Furanyl)-4-amino-5-mercapto-1,2,4-triazole (1) was prepared from 2-furoic acid through a multi-step reaction sequence. Compound 1 reacted with aromatic acids in the presence of phosphorus oxychloride to give 3-(2-furanyl)-6-aryl-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazoles (2). The structures of all the newly synthesized compounds have been confirmed by elemental analysis, IR, 1H-NMR, 13C-NMR and mass spectra. The bioassay indicated most of the title compounds possess significant growth prom...

Li-Xue Zhang; An-Jiang Zhang; Xian-Xing Chen; Xin-Xiang Lei; Xiang-Yun Nan; Dong-Yong Chen; Zi-Yi Zhang

2002-01-01

377

Rhodium-catalyzed direct ortho C-N bond formation of aromatic azo compounds with azides.  

Science.gov (United States)

An efficient rhodium-catalyzed regioselective C-N bond formation of azo compounds in good to excellent yields through C-H bond functionalization using azides as the nitrogen source was developed. Alkyl, aryl, and sulfonyl azides could be efficiently assembled in this reaction with excellent functional group tolerance. PMID:24635190

Wang, Hao; Yu, Yang; Hong, Xiaohu; Tan, Qitao; Xu, Bin

2014-04-01

378

sp3 C-H bond arylation directed by amidine protecting group: alpha-arylation of pyrrolidines and piperidines.  

Science.gov (United States)

A new ruthenium-catalyzed direct sp3 C-H to C-C bond transformation is disclosed. Specifically, a method for the alpha-arylation of cyclic amines, containing either permanent (pyridine, pyrimidine) or removable (amidine) directing groups, is described. This cross-coupling reaction involves heating amine substrates with arylboronate ester at 150 degrees C in a ketone solvent with a catalytic amount of ruthenium carbonyl [Ru3(CO)12]. Arylboronate esters containing either electron-withdrawing or electron-donating substituents could be efficiently coupled. Heteroarene boronates were also effective donors. PMID:17076471

Pastine, Stefan J; Gribkov, Denis V; Sames, Dalibor

2006-11-01

379

Quercetin, resveratrol, and curcumin are indirect activators of the aryl hydrocarbon receptor (AHR).  

Science.gov (United States)

Several polyphenols have been shown to activate the aryl hydrocarbon receptor (AHR) in spite of the fact that they bind to the receptor with low affinity. The aim of this study was to investigate whether quercetin (QUE), resveratrol (RES), and curcumin (CUR) interfere with the metabolic degradation of the suggested endogenous AHR ligand 6-formylindolo[3,2-b]carbazole (FICZ) and thereby indirectly activate the AHR. Using recombinant human enzyme, we confirmed earlier reported inhibitory effects of the polyphenols on cytochrome P4501A1 (CYP1A1) activity, and inhibition of metabolic clearance of FICZ was documented in FICZ-treated immortalized human keratinocytes (HaCaT). CYP1A1 activity was induced in HaCaT cells by all three compounds, and when they were added together with FICZ, a prolonged activation was observed after a dose-dependent inhibition period. The same pattern of responses was seen at the transcriptional level as determined with a CYP1A1 reporter assay in human liver hepatoma (HepG2) cells. To test the ability of the polyphenols to activate the AHR in the absence of FICZ, the cells were treated in medium, which in contrast to commercial batches of medium did not contain background levels of FICZ. Importantly, AHR activation was only observed in the commercial medium. Taken together, these findings suggest that QUE, RES, and CUR induce CYP1A1 in an indirect manner by inhibiting the metabolic turnover of FICZ. Humans are exposed to these compounds through the diet and nutritional supplements, and we propose that altered systemic levels of FICZ caused by such compounds may have physiological consequences. PMID:22867086

Mohammadi-Bardbori, Afshin; Bengtsson, Johanna; Rannug, Ulf; Rannug, Agneta; Wincent, Emma

2012-09-17

380

Synthesis, Spectroscopy and Electrochemistry of New 3-(5-Aryl-4,5-Dihydro-1H-Pyrazol-3-yl)-4-Hydroxy-2H-Chromene-2-One 4, 5 as a Novel Class of Potential Antibacterial and Antioxidant Derivatives  

Digital Repository Infrastructure Vision for European Research (DRIVER)

3-((2E)-3(aryl)prop-2-enoyl)-2H-chromen-2-one 3 was synthesized from 4-hydroxy coumarin by refluxing 3-acetyl-4-hydroxy coumarin with aromatic aldehydes in chloroform in the presence of a catalytic amount of piperidine. 3 was converted to pyrazoles 4, 5 by treatment with hydrazine and phenylhydrazine in toluene, respectively. The structures of the new compounds were confirmed by elemental analysis, IR, and multinuclear/multidimensional ...

Abdullah Sulaiman Al-Ayed

2011-01-01

 
 
 
 
381

Responsiveness of a Xenopus laevis cell line to the aryl hydrocarbon receptor ligands 6-formylindolo[3,2-b]carbazole (FICZ) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aryl hydrocarbon receptor (AHR) mediates the toxic effects of environmental contaminants, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Frogs are very insensitive to TCDD toxicity, and AHRs from Xenopus laevis (African clawed frog) bind TCDD with >20-fold lower affinity than mouse AHRb-1. Frog AHRs may nonetheless be highly responsive to structurally distinct compounds, especially putative endogenous ligands. We sought to determine the responsiveness of an X. laevis cell line, XLK-W...

Laub, Leo B.; Jones, Brian D.; Powell, Wade H.

2010-01-01

382

In vitro microbiological evaluation of 1,1'-(5,5'-(1,4-phenylene)bis(3-aryl-1H-pyrazole-5,1-(4H,5H)-diyl))diethanones, novel bisacetylated pyrazoles  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Novel 1,1'-(5,5'-(1,4-phenylene)bis(3-aryl-1H-pyrazole-5,1-(4H,5H)-diyl))diethanones 7-12 were tested for their antimicrobial activity by disc diffusion and twofold serial dilution method against the tested bacterial and fungal strains. Compounds 7 against Micrococcus luteus, 8 against ?-Heamolytic streptococcus, M. luteus, Klebsiella pneumonia, Microsporum gypseum, 9 against Staphylococcus aureus, Shigella flexneri, Vibreo cholerae, Pseudomonas aeruginosa, Aspergillus flavus, Mucor indicus,...

Kanagarajan, Vijayakumar; Ezhilarasi, Muthuvel Ramanathan; Gopalakrishnan, Mannathusamy

2011-01-01

383

Pd-carbene catalyzed carbonylation reactions of aryl iodides.  

Science.gov (United States)

A series of carbene complexes [PdBr(2)((i)Pr(2)-bimy)L] (C2-C13) with different types of co-ligands (L) have been tested for their catalytic activities in the carbonylative annulation of 2-iodophenol with phenylacetylene in DMF to afford the respective flavone 2a. Complex C12 with an N-phenylimidazole co-ligand showed the best activity and also afforded high yields when the substrate scope was extended to other aryl or pyridyl acetylenes. In addition, catalyst C12 was also efficient in the carbonylative annulation of 2-iodoaniline with acid chlorides giving the desirable 2-substituted 4H-3,1-benzoxazin-4-ones (4) in good yields. Additionally, this Pd-NHC complex also proved to be a very efficient catalyst for the hydroxycarbonylation of iodobenzene derivatives at low catalyst loading and under low CO pressure. These results demonstrate the versatility and efficiency of this phosphine-free Pd(II)-NHC complex in different types of carbonylations of aryl iodides under mild conditions. PMID:21677940

Xue, Liqin; Shi, Lijun; Han, Yuan; Xia, Chungu; Huynh, Han Vinh; Li, Fuwei

2011-08-01

384

Generation of detectable singlet aryl cations by photodehalogenation of fluoroquinolones.  

Science.gov (United States)

Nanosecond laser flash photolysis (lambdaexc = 355 nm) of neutral aqueous solutions of lomefloxacin (LFX, a 8-fluorinated 7-amino-4-quinolone-3-carboxylic acid derivative) produces a detectable transient species, which shows an absorption maximum at 490 nm and can be assigned to an aryl cation. This intermediate has a lifetime of ca. 200 ns in net water, reacts with Br- and Cl- with rate constants of 3.6 x 10(9) M(-1) s(-1) and 4.1 x 10(8) M(-1) s(-1), respectively, and shows a lack of reactivity toward molecular oxygen. From the photolysis of BAY y3118 (BAY, a 8-chlorinated analogue), an aryl cation is also generated, showing absorption maximum at 480 nm (lifetime of ca. 1 micros in net water) and a reaction rate constant of 9 x 10(9) M(-1) s(-1) with Br(-). The existence of these highly reactive species arising from direct photolysis of LFX and BAY can justify the photogenotoxic properties associated with these antibacterial drugs likely due to direct reaction of their cations with DNA. PMID:16570937

Cuquerella, M Consuelo; Miranda, Miguel A; Bosca, Francisco

2006-04-01

385

Metal-free arylation of oxygen nucleophiles with diaryliodonium salts.  

Science.gov (United States)

Phenols and carboxylic acids are efficiently arylated with diaryliodonium salts. The reaction conditions are mild, metal free, and avoid the use of halogenated solvents, additives, and excess reagents. The products are obtained in good-to-excellent yields after short reaction times. Steric hindrance is very well tolerated, both in the nucleophile and diaryliodonium salt. The scope includes ortho- and halo-substituted products, which are difficult to obtain by metal-catalyzed protocols. Many functional groups are tolerated, including carbonyl groups, heteroatoms, and alkenes. Unsymmetric salts can be chemoselectively utilized to obtain products with hitherto unreported levels of steric congestion. The arylation has been extended to sulfonic acids, which can be converted to sulfonate esters by two different approaches. With recent advances in efficient synthetic procedures for diaryliodonium salts the reagents are now inexpensive and readily available. The iodoarene byproduct formed from the iodonium reagent can be recovered quantitatively and used to regenerate the diaryliodonium salt, which improves the atom economy. PMID:23015511

Jalalian, Nazli; Petersen, Tue B; Olofsson, Berit

2012-10-29

386

Nickel-Mediated Hydrogenolysis of C-O Bonds of Aryl Ethers: What Is the Source of the Hydrogen?  

Science.gov (United States)

Mechanistic studies of the hydrogenolysis of aryl ethers by nickel were undertaken with (diphosphine)aryl methyl ethers. A Ni(0) complex containing Ni-arene interactions adjacent to the aryl-O bond was isolated. Heating led to aryl-O bond activation and generation of a nickel-aryl-methoxide complex. Formal ?-H elimination from this species produced a nickel-aryl-hydride which can undergo reductive elimination in the presence of formaldehyde to generate a carbon monoxide adduct of Ni(0). The reported complexes map out a plausible mechanism of aryl ether hydrogenolysis catalyzed by nickel. Investigations of a previously reported catalytic system using isotopically labeled substrates are consistent with the mechanism proposed in the stoichiometric system, involving ?-H elimination from a nickel alkoxide rather than cleavage of the Ni-O bond by H2.

Kelley, Paul; Lin, Sibo; Edouard, Guy; Day, Michael W.; Agapie, Theodor

2012-01-01

387

Synthesis of Novel 3-Aryl-N-Methyl-1,2,5,6-Tetrahydropyridine Derivatives by Suzuki coupling: As Acetyl Cholinesterase Inhibitors  

Science.gov (United States)

Alzheimers disease (AD) is a neurodegenerative disorder affecting the central nervous system, which is also associated with progressive loss of memory and cognition. The development of numerous structural classes of compounds with different pharmacological profile could be an evolving, promising therapeutic approach for the treatment of AD. Thus, providing a symptomatic treatment for this disease are cholinomimetics with the pharmacological profile of Acetylcholinesterase (AChE) inhibitors. In view of this, we have synthesized novel 3-aryl-N-methyl-1,2,5,6-tetrahydropyridine derivatives 5a-k by Suzuki coupling and screened the efficacy of these derivatives for their AChE inhibitor activity.

Prasad, S.B. Benaka; Kumar, Y.C. Sunil; Kumar, C.S. Ananda; Sadashiva, C.T; Vinaya, K; Rangappa, K.S

2007-01-01

388

Principal component analysis for verifying 1H NMR spectral assignments. The case of 3-aryl (1,2,4)-oxadiazole-5-carbohydrazide benzylidene  

International Nuclear Information System (INIS)

The 1H NMR data set of a series of 3-aryl (1,2,4)-oxadiazole-5-carbohydrazide benzylidene derivatives synthesized in our group was analyzed using the chemometric technique of principal component analysis (PCA). Using the original 1H NMR data PCA allowed identifying some misassignments of the proton aromatic chemical shifts. As a consequence of this multivariate analysis, nuclear Overhauser difference experiments were performed to investigate the ambiguity of other assignments of the ortho and meta aromatic hydrogens for the compound with the bromine substituent. The effect of the 1,2,4-oxadiazole group as an electron acceptor, mainly for the hydrogens 12,13, has been highlighted. (author)

2005-01-01

389

Microwave-assisted efficient synthesis of 2-hydroxydeoxybenzoins from the alkali degradation of readily prepared 3-aryl-4-hydroxycoumarins in water.  

Science.gov (United States)

This paper describes an operationally simple, green and efficient approach for the synthesis of 2-hydroxydeoxybenzoins bearing diverse substituents from the microwave-assisted alkali degradation of 3-aryl-4-hydroxycoumarins in water. The latter compounds were readily prepared from the intramolecular Claisen condensation reaction of methyl 2-(2-arylacetoxy)benzoates in the presence of Cs2CO3-acetone, in excellent yields and without laborious workup procedures. This method is highly atom-economic and thus applicable for the large-scale synthesis of 2-hydroxydeoxybenzoins. PMID:24189303

Zhou, Zhong-Zhen; Yan, Guang-Hua; Chen, Wen-Hua; Yang, Xue-Mei

2013-01-01

390

Synthesis and SAR studies of novel 2-(4-oxo-2-aryl-quinazolin-3(4H)-yl)acetamide vasopressin V1b receptor antagonists.  

Science.gov (United States)

Synthesis and structure-activity relationships (SAR) of a novel series of vasopressin V(1b) (V(3)) antagonists are described. 2-(4-Oxo-2-aryl-quinazolin-3(4H)-yl)acetamides have been identified with low nanomolar affinity for the V(1b) receptor and good selectivity with respect to related receptors V(1a), V(2) and oxytocin (OT). Optimised compound 12j demonstrates a good pharmacokinetic profile and activity in a mechanistic model of HPA dysfunction. PMID:21353540

Napier, Susan E; Letourneau, Jeffrey J; Ansari, Nasrin; Auld, Douglas S; Baker, James; Best, Stuart; Campbell-Wan, Leigh; Chan, Jui-Hsiang; Craighead, Mark; Desai, Hema; Goan, Katharine A; Ho, Koc-Kan; Hulskotte, Ellen G J; MacSweeney, Cliona P; Milne, Rachel; Morphy, J Richard; Neagu, Irina; Ohlmeyer, Michael H J; Peeters, Ard W M M; Presland, Jeremy; Riviello, Chris; Ruigt, Ge S F; Thomson, Fiona J; Zanetakos, Heather A; Zhao, Jiuqiao; Webb, Maria L

2011-03-15

391

Cytotoxicity and topoisomerase I/II inhibition activity of novel 4-aryl/alkyl-1-(piperidin-4-yl)-carbonylthiosemicarbazides and 4-benzoylthiosemicarbazides.  

Science.gov (United States)

A series of eight thiosemicarbazide derivatives was examined for cytotoxicity in breast cancer cell cultures. Among them, 4-benzoylthiosemicarbazides proved to be only slightly less potent than chlorambucil in both MDA-MB-231 and MCF-7 lines. In contrast, 4-aryl/alkylthiosemicarbazides revealed significantly lower cytotoxicity effect. Subsequently, all titled compounds were tested as potential human topoisomerase I and II (topo I and topo II) inhibitors. Mechanistic studies revealed that tested thiosemicarbazides act as both topoisomerase I and topoisomerase II inhibitors. Among them, the best inhibitory activity was found for 4-benzoylthiosemicarbazides (1 and 2) with IC50 at 50 M against topo II. PMID:23432612

Siwek, Agata; Bielawska, Anna; Maciorkowska, Elzbieta; Lepiarczyk, Monika; Bielawski, Krzysztof; Trotsko, Nazar; Wujec, Monika

2014-04-01

392

Syntheses and Biological Activities of 6-Aryl-3-(3-hydroxy- propyl-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines  

Directory of Open Access Journals (Sweden)

Full Text Available A series of 6-aryl-3-(3-hydroxypropyl-7H-1,2,4-triazolo[3,4-b][1,3,4]-thia-diazines were synthesized by the reaction of 4-amino-3-(3-hydroxypropyl-5-mercapto-1,2,4-triazole (1 with substituted ?-haloacetophenones. Their structures were confirmed by elemental analysis, IR, 1H-NMR, and 13C-NMR. Tests of plant growth regulating effects showed that the title compounds display remarkable inhibitory activities on the growth of radish and wheat.

Hai-le Zhang

2007-03-01

393

Synthesis and serotonin transporter activity of 1,3-bis(aryl)-2-nitro-1-propenes as a new class of anticancer agents  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Structural derivatives of 4-MTA, an illegal amphetamine analogue have been previously shown to have anticancer effects in vitro. In this study we report the synthesis of a series of novel 1,3-bis(aryl)-2-nitro-1-propene derivatives related in structure to 4-MTA. A number of these compounds containing a classic nitrostyrene structure are shown to have antiproliferative activities in vitro in a range of malignant cell lines, particularly against Burkitts lymphoma derived cell lines, whilst h...

Knox, Andrew; Williams, David Clive; Meegan, Mary Jane; Cloonan, Suzanne; Mcnamara, Yvonne

2011-01-01

394

Ruthenium catalyzed decarbonylative arylation at sp3 carbon centers in pyrrolidine and piperidine heterocycles.  

Science.gov (United States)

This paper describes the development of a new catalytic transformation, the ruthenium-catalyzed decarbonylative arylation of cyclic 2-amino esters, which replaces the ester group with an aryl ring at the sp3 carbon center. For example, proline ester amidine 1 is converted to 2-arylpyrrolidine 3 in the presence of arylboronic acids or esters as arene donors and Ru(3)(CO)(12) as the catalyst. This process provides a rapid access to a variety of 2-arylpyrrolidines and piperidines from commercially available proline, hydroxyproline, and pipecolinate esters. The examination of the substrate scope also showed that many arene boronic acids and boronate esters serve as coupling partners. The high chemoselectivity of this process was demonstrated and ascribed to the significant rate difference between the decarbonylative arylation and the C-H arylation. The decarbonylative arylation complements the C-H arylation, since the latter process lacks control over the extent of functionalization, affording a mixture of mono- and bis-arylpyrrolidines. When applied in tandem, these two processes provide 2,5-diarylpyrrolidines in two steps from the corresponding proline esters. It was also demonstrated that the required amidine or iminocarbamate directing group fulfills two major functions: first, it is essential for the ester activation step, which occurs via the coordination-assisted metal insertion into the acyl C-O bond; second, it facilitates the decarbonylation, via the stabilization of a metallacycle intermediate, assuring the formation of the 2-arylated products instead of the corresponding ketones observed before by others. PMID:17803274

Gribkov, Denis V; Pastine, Stefan J; Schnrch, Michael; Sames, Dalibor

2007-09-26

395

The stable aryl hydrocarbon receptor agonist potency of United Kingdom Continental Shelf (UKCS) offshore produced water effluents.  

Science.gov (United States)

The in vitro aryl hydrocarbon receptor (AhR) agonist potency of offshore produced water effluents, collected from the United Kingdom Continental Shelf, was determined using the dioxin responsive (DR)-chemically activated luciferase expression (CALUX) assay. Octadecylsilane (C18) solid phase extraction (SPE) extracts of produced water were exposed to DR-CALUX cells for 24h in order to investigate the contribution in potency from compounds that are stable to metabolism by the CALUX cells during exposure. The stable AhR agonist potency determined over 24h was highly variable and ranged from 1 to 430 ng TCDD TEQ(CALUX)l(-1). These data reflect the highly variable composition of produced water discharges from different production fields. It is recommended that further work be performed to characterise the full range of stable dioxin like AhR agonists present in offshore produced water discharges using techniques such as bioassay-directed analysis. PMID:16126234

Hurst, Mark R; Chan-Man, Yin L; Balaam, Jan; Thain, John E; Thomas, Kevin V

2005-12-01

396

Synthesis and antitubercular evaluation of novel substituted aryl and thiophenyl tethered dihydro-6H-quinolin-5-ones.  

Science.gov (United States)

A series of novel aryl and thiophenyl tethered dihydro-6H-quinolin-5-ones have been synthesized in very good yields through CeCl(3)7H(2)O-NaI catalyzed one-pot condensation of ?-enaminones derived from the respective methyl ketones; 1,3-cyclohexanedione & 5,5-dimethyl-1,3-cyclohexanedione and ammonium acetate refluxing in 2-propanol. Dihydro-6H-quinolin-5-ones 3a-f was further derivatized to the respective hydroxymethyl analogs using proline as an organocatalyst in aqueous media. Among the all 18 compounds screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H(37)Rv (MTB), dihydro-6H-quinolin-5-ones 4e and 4f were found to be most active with MIC 3.13 ?g/mL. PMID:21237641

Kantevari, Srinivas; Patpi, Santhosh Reddy; Sridhar, Balasubramanian; Yogeeswari, Perumal; Sriram, Dharmarajan

2011-02-15

397

SYNTHESIS AND BIOLOGICAL ACTIVITIES OF CERTAIN MESOIONIC SYDNONE COMPOUNDS CONTAINING CHALCONE MOIETY  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to have antibacterial, analgesic and anti-inflammatory activity in the same molecule, 4-[1-oxo-3- (substituted aryl)-2-propenyl]-3-(4-chlorophenyl)sydnones were synthesized by condensing 4-acetyl-3-(4-chlorophenyl)sydnone with various substituted aryl aldehydes and characterized by spectral studies; 4-acetyl-3-(4-chlorophenyl)sydnone itself, was prepared by acetylation of 3-(4-chlorophenyl)sydnone. The newly synthesized compounds were evaluated for antibacterial and anti-inflammatory...

2010-01-01

398

Synthesis and pharmacological investigation of novel 1-alkyl-4-(4-substituted aryl/heteroaryl)-1,2,4-triazolo [4,3- a] quinazolin-5 (4H)-ones as a new class of H1-antihistaminic agents.  

Science.gov (United States)

A series of novel 1-alkyl-4-(4-substituted aryl/heteroaryl)- 1,2,4-triazolo [4,3-a] quinazolin-5(4H)-ones were synthesized by the cyclization of 2-hydrazino-3-(4-subst. aryl/heteroaryl) quinazolin-4(3H)-one with various carbon donors. The starting material, 2-hydrazino-3-(4-subst. aryl/heteroaryl) quinazolin-4(3H)-one, was synthesized from 4-subst. arylamine/ heteroarylamine by a novel innovative route. When tested for their in vivo Hi-antihistaminic activity on conscious guinea pigs, all the test compounds protected the animals from histamine induced bronchospasm significantly, whereby the compound 1-methyl-4-(2-py-ridyl)-1,2,4-triazolo[4,3-a] quinazolin-5(4H)-one (II) was found to be more potent (percent protection 71.43 %) when compared to the reference standard, chlorpheniramine maleate (percent protection 71 %). Compound II showed negligible sedation (8 %) when compared to chlorpheniramine maleate (25 %). Hence it could serve as prototype molecule for further development as a new class of H1-antihistamines. PMID:17260671

Alagarsamy, Veerachamy; Yadav, Mangae Ram; Giridhar, Rajani

2006-01-01

399

Enzymatic aryl-O-methyl-"1"4C labeling of model lignin monomers  

International Nuclear Information System (INIS)

Aryl-O-methyl ethers are abundant in aerobic and anaerobic environments. In particular, lignin is composed of units of this type. Lignin monomers specifically radiolabeled in methoxy, side chain, and ring carbons have been synthesized by chemical procedures and are important in studies of lignin synthesis and degradation, humus formation, and microbial O-demethylation. In this paper attention is drawn to an enzymatic procedure for preparing O-methyl-"1"4C-labeled aromatic lignin monomers which has not previously been exploited in microbial ecology and physiology studies and which has several advantages compared with chemical synthesis procedures. O-[methyl-"1"4C]vanillic and O-[methyl-"1"4C]ferulic acids were prepared with S-[methyl-"1"4C]adenosyl-L-methionine as the methyl donor, using commercially obtained porcine liver catechol-O-methyltransferase (EC 2.1.1.6). The specific activity of the methylated products was the same as that of the methyl donor, a maximum of about 58 ?Ci/?mol, and the yields were 42% (vanillate) and 35% (ferulate). Thus lignin monomers are readily prepared as O-methylated products of the catechol-O-methyltransferase reaction and, with this enzyme method of preparation, would be more widely available than labeled compounds which require chemical synthesis

1986-01-01

400

Aryl hydrocarbon receptor-dependent cell cycle arrest in isolated mouse oval cells.  

Science.gov (United States)

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor, which mediates toxic responses to environmental pollutants, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. Besides its well known role in induction of xenobiotic metabolizing enzymes, for instance CYP1A1, the AhR is also involved in tumor promotion in rodents although the underlying mechanisms are still poorly understood. Additionally, the AhR is known to regulate cellular proliferation, which might result in either inhibition or stimulation of proliferation depending on the cell-type studied. Potential targets in hepatocarcinogenesis are liver oval (stem/progenitor) cells. In the present work we analyzed the effect of TCDD on proliferation in oval cells derived from mouse liver. We show that TCDD inhibits proliferation in these cells. In line, the amount of G0/G1 cells increases in response to TCDD. We further show that the expression of cyclin D1 and cyclin A is decreased, while p27 is increased. As a result, the retinoblastoma protein is not phosphorylated thereby inducing G0/G1 arrest. Pharmacological inhibition of the AhR and knock-down of AhR expression by RNA interference decreased the inhibitory effect on cell cycle and protein expression, indicating that the AhR at least partially mediates cell cycle arrest. PMID:24013123

Faust, Dagmar; Kletting, Stephanie; Ueberham, Elke; Dietrich, Cornelia

2013-10-23

 
 
 
 
401

The aryl hydrocarbon receptor modulates acute and late mast cell responses.  

Science.gov (United States)

The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor whose activity is modulated by xenobiotics as well as physiological ligands. These compounds may modulate inflammatory responses and contribute to the rising prevalence of allergic diseases observed in industrialized countries. Mast cells (MCs), located within tissues at the boundary of the external environment, represent a potential target of AhR ligands. In this study, we report that murine and human MCs constitutively express AhR, and its activation by the high-affinity ligand 6-formylindolo[3,2-b]carbazole (FICZ) determines a boost in degranulation. On the contrary, repeated exposure to FICZ inhibits MC degranulation. Accordingly, histamine release, in an in vivo passive systemic anaphylactic model, is exacerbated by a single dose and is attenuated by repetitive stimulation of AhR. FICZ-exposed MCs produce reactive oxygen species and IL-6 in response to cAMP-dependent signals. Moreover, AhR-activated MCs produce IL-17, a critical player in chronic inflammation and autoimmunity, suggesting a novel pathway for MC activation in the pathogenesis of these diseases. Indeed, histological analysis of patients with chronic obstructive pulmonary disease revealed an enrichment in AhR/IL-6 and AhR/IL-17 double-positive MCs within bronchial lamina propria. Thus, tissue-resident MCs could translate external chemical challenges through AhR by modulating allergic responses and contributing to the generation of inflammation-related diseases. PMID:22649193

Sibilano, Riccardo; Frossi, Barbara; Calvaruso, Marco; Danelli, Luca; Betto, Elena; Dall'Agnese, Alessandra; Tripodo, Claudio; Colombo, Mario P; Pucillo, Carlo E; Gri, Giorgia

2012-07-01

402

Effects of perfluoroalkyl acids on the function of the thyroid hormone and the aryl hydrocarbon receptor  

DEFF Research Database (Denmark)

Perfluoroalkyl acids (PFAAs) are perfluorinated compounds that widely exist in the environment and can elicit adverse effects including endocrine disruption in humans and animals. This study investigated the effect of seven PFAAs on the thyroid hormone (TH) system assessing the proliferation of the 3,3',5-triiodo-L-thryonine (T3)-dependent rat pituitary GH3 cells using the T-screen assay and the effect on the aryl hydrocarbon receptor (AhR) transactivation in the AhR-luciferase reporter gene bioassay. A dose-dependent impact on GH3 cells was observed in the range 1?????10(-9)-1?????10(-4) M: seven PFAAs (perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA)) inhibited the GH3 cell growth, and four PFAAs (PFOS, PFHxS, PFNA, and PFUnA) antagonized the T3-induced GH3 cell proliferation. At the highest test concentration, PFHxS showed a further increase of the T3-induced GH3 growth. Among the seven tested PFAAs, only PFDoA and PFDA elicited an activating effect on the AhR. In conclusion, PFAAs possess in vitro endocrine-disrupting potential by interfering with TH and AhR functions, which need to be taken into consideration when assessing the impact on human health.

Long, Manhai; Ghisari, Mandana

2013-01-01

403

Cyclopentyl methyl ether: an alternative solvent for palladium-catalyzed direct arylation of heteroaromatics.  

Science.gov (United States)

Some ethers, such as cyclopentyl methyl ether and di-n-butyl ether, which can be considered as "greener" solvents than N,N-dimethylacetamide (DMAc) or DMF, can be advantageously employed for the palladium-catalyzed direct arylation of heteroaromatics. In the presence of such ethers and only 0.5-1?mol?% of palladium catalysts at 125-150?C, the direct 5-arylation of thiazoles, thiophenes, or furans by using aryl bromides as coupling partners proceeds in moderate to high yields. PMID:21337529

Beydoun, Kassem; Doucet, Henri

2011-04-18

404

Nickel-catalyzed cross-coupling of aryl fluorides and organozinc reagents.  

Science.gov (United States)

Ni(PCy3)2Cl2 was demonstrated to effectively catalyze cross-coupling of aryl fluorides and organozinc reagents. Both electron-poor and -rich aryl fluorides can react effectively with nucleophiles including aryl-, methyl-, and benzylzinc chlorides. A wide range of substituents and functional groups are tolerated. In the presence of a directing group, PhC(O), the reaction is selective for cleavage of the C-F bond ortho to the carbonyl substituent in a difluoroarene. PMID:24758137

Zhu, Feng; Wang, Zhong-Xia

2014-05-16

405

Base-promoted formal arylation of benzo[d]oxazoles with acyl chloride.  

Science.gov (United States)

A base-promoted formal arylation of benzo[d]oxazoles with acyl chloride was achieved in moderate to good yields. This reaction was triggered by the N-acylation of oxazole to form an iminium intermediate. Then, the addition of H2O to the iminium formed the hemiacetal intermediate. After the sequential ring-opening, extrusion of CO, the ring closure, the dehydration delivered the formal arylation product. In comparison with the transition-metal-catalyzed methodology, it represents an alternative arylation method leading to 2-arylbenzooxazole. PMID:24195716

Wang, Lei; Ren, Xinyi; Yu, Jintao; Jiang, Yan; Cheng, Jiang

2013-12-01

406

Manganese(IV)-Mediated Hydroperoxyarylation of Alkenes with Aryl Hydrazines and Dioxygen from Air.  

Science.gov (United States)

We report a new carbooxygenation-type version of the Meerwein arylation in which the introduction of oxygen is achieved by using dioxygen from the air. In this way, hydroperoxides were obtained from activated as well as non-activated alkenes by oxidizing aryl hydrazines with manganese dioxide. The best results were obtained with ?-substituted acrylates. Importantly, the aryl hydrazine has to be added slowly to the reaction mixture to allow sufficient uptake of dioxygen from the air. Competition and labeling experiments revealed hydroperoxyl radicals as novel oxygen-centered radical scavengers. PMID:24737215

Kindt, Stephanie; Jasch, Hannelore; Heinrich, Markus R

2014-05-19

407

An efficient one pot syntheses of aryl-3,3'-bis(indolyl)methanes and studies on their spectral characteristics, DPPH radical scavenging-, antimicrobial-, cytotoxicity-, and antituberculosis activity.  

Science.gov (United States)

An efficient one-pot syntheses of aryl-3,3'-bis(indolyl)methanes (BIMs) from indole/2-methylindole and formylphenoxyaliphatic acid(s) is described. Esterification of carboxylic acid and aromatic electrophilic substitution reactions are achieved simultaneous in the presence of potash alum as a catalyst. This catalyst could be recovered and reused without substantial loss in its catalytic activity and the methodology could be applied on a range of closely related substrates. The solvation characteristics in ground and excited states of the compounds by monitoring the absorbance and fluorescence band maxima have been studied. The fluorescence studies in protic and aprotic solvents were rationalized on the basis of solute-solvent interaction and substituents effect on these photophysical processes analyzed. The compounds prepared showed efficient antimicrobial effect against human pathogens, cytotoxicity against A431 cell line, and DPPH radical scavenging effect. Single crystal XRD studies have been carried out for a few compounds synthesized in this work. PMID:23103467

Kumar, G S Suresh; Kumaresan, S; Muthu Prabhu, A Antony; Bhuvanesh, N; Seethalakshmi, P G

2013-01-15

408

An efficient one pot syntheses of aryl-3,3'-bis(indolyl)methanes and studies on their spectral characteristics, DPPH radical scavenging-, antimicrobial-, cytotoxicity-, and antituberculosis activity  

Science.gov (United States)

An efficient one-pot syntheses of aryl-3,3'-bis(indolyl)methanes (BIMs) from indole/2-methylindole and formylphenoxyaliphatic acid(s) is described. Esterification of carboxylic acid and aromatic electrophilic substitution reactions are achieved simultaneous in the presence of potash alum as a catalyst. This catalyst could be recovered and reused without substantial loss in its catalytic activity and the methodology could be applied on a range of closely related substrates. The solvation characteristics in ground and excited states of the compounds by monitoring the absorbance and fluorescence band maxima have been studied. The fluorescence studies in protic and aprotic solvents were rationalized on the basis of solute-solvent interaction and substituents effect on these photophysical processes analyzed. The compounds prepared showed efficient antimicrobial effect against human pathogens, cytotoxicity against A431 cell line, and DPPH radical scavenging effect. Single crystal XRD studies have been carried out for a few compounds synthesized in this work.

Suresh Kumar, G. S.; Kumaresan, S.; Antony Muthu Prabhu, A.; Bhuvanesh, N.; Seethalakshmi, P. G.

2013-01-01

409

Selective transformations of substituted aryl compounds to fluorenes and phosphoramidates : synthetic and spectroscopic studies  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Because of their diverse biological properties and their high potential for the development of new drugs the synthesis of fluorenes and related systems such as benzo[b]fluorenes is of great interest in the fields of organic and medicinal chemistry. The most relevant benzo[b]fluorenes include the naturally occurring kinamycins. Recently, two fluorene derivatives have been isolated from the sweat of hippopotamus (Hippopotamus amphibius). The biological function of the two dyes named hipposudori...

Haggam, Reda

2010-01-01

410

Screening of indigenous plants from Japan for modulating effects on transformation of the aryl hydrocarbon receptor.  

Science.gov (United States)

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor with which halogenated and polycyclic aromatic hydrocarbons such as dioxins and benzo[a]pyrene interact as ligands. Since such compounds cause various toxicological effects, including cancer, through the transformation of AhR, it is important to determine influence of modulating factors. It has been reported that certain plant components such as flavonoids and indoles can affect AhR transformation. In this study, to obtain clues to novel ligands of AhR, 191 species of indigenous plants were collected in Japan, and their 50% methanolic extracts (total 368 plant parts) were tested for modulating effects on AhR transformation in a cell-free system using a rat hepatic cytosolic fraction. Among tested extracts at a concentration of 1 mg dry weight of plant/mL, 174 of 368 extracts suppressed 1 nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced AhR transformation to 50% or less, while 9 extracts per se induced AhR transformation equivalent to more than 20% of that induced by 1 nM TCDD. Mallotus japonicus (Thunb.) Muell. (leaf) and Trichosanthes rostrata Kitamura (fruit and fruit skin) strongly suppressed 1 nM TCDD-induced AhR transformation, while Phellodendron amurense Ruprecht (seed) per se strongly induced AhR transformation. These results suggest that a large variety of plants in Japan contain various compounds modulating, mainly suppressing, AhR transformation. PMID:16839212

Nishiumi, Shin; Hosokawa, Keizo; Mukai, Rie; Fukuda, Itsuko; Hishida, Atsuyuki; Iida, Osamu; Yoshida, Ken-ichi; Ashida, Hitoshi

2006-01-01

411

Aryl hydrocarbon mono-oxygenase activity in human lymphocytes  

Energy Technology Data Exchange (ETDEWEB)

Aryl hydrocarbon mono-oxygenase (AHM), an enzyme of key importance in metabolism of xenobiotic chemicals such as polynuclear aromatic hydrocarbons (PNA), is present in human lymphocytes. Studies investing the relation of activity of AHM in human lymphocytes to parameters such as disease state, PNA exposure, in vitro mitogen stimulation, etc. have been summarized in this report. Some studies have demonstrated increased AHM activity in lymphocytes from cigarette smokers (compared to nonsmokers), and in lung cancer patients when compared to appropriate control groups. These observations are confused by extreme variability in human lymphocyte AHM activities, such variability arising from factors such as genetic variation in AHM activity, variation in in vitro culture conditions which affect AHM activity, and the problematical relationship of common AHM assays to actual PNA metabolism taking place in lymphocytes. If some of the foregoing problems can be adequately addressed, lymphocyte AHM activity could hold the promise of being a useful biomarker system for human PNA exposure.

Griffin, G.D.; Schuresko, D.D.

1981-06-01

412

Isolable aryl-substituted silyl radicals: synthesis, characterization, and reactivity.  

Science.gov (United States)

Isolable aryl-substituted silyl radicals (tBu2 MeSi)2 (Ar)Si(.) (Ar=C6 H5 , 4-tBuC6 H4 , 4-PhC6 H4 , 3,5-tBu2 C6 H3 ) were synthesized by the reaction of the corresponding iodosilane with an equimolar amount of potassium graphite (KC8 ) in tetrahydrofuran (THF). The crystal structure of 3,5-tBu2 C6 H3 derivative, which was determined by X-ray crystallography, showed a planar geometry around the Si atom for the radical center. EPR studies of all four radicals revealed the lack of the delocalization of the unpaired electron over the aromatic ring. Reactivity and spectroscopic studies of the less-hindered phenyl-substituted silyl radical showed that it exists as an equilibrium mixture of the radical and its silene-type dimer in solution. PMID:24909557

Taira, Kanako; Ichinohe, Masaaki; Sekiguchi, Akira

2014-07-21

413

The Aryl Hydrocarbon Receptor: A Target for Breast Cancer Therapy  

Directory of Open Access Journals (Sweden)

Full Text Available The aryl hydrocarbon receptor (AhR is a ligand-activated transcription factor that regulates a battery of genes in response to exposure to a broad class of environmental poly aromatic hydrocarbons (PAH. AhR is historically characterized for its role in mediating the toxicity and adaptive responses to these chemicals, however mounting evidence has established a role for it in ligand-independent physiological processes and pathological conditions, including cancer. The AhR is overexpressed and constitutively activated in advanced breast cancer cases and was shown to drive the progression of breast cancer. In this article we will review the current state of knowledge on the possible role of AhR in breast cancer and how it will be exploited in targeting AhR for breast cancer therapy.

Joann B. Powell

2013-08-01

414

Reduction of alkyl and aryl azides with sodium thiophosphate in aqueous solutions.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A simple aqueous method for the conversion of alkyl and aryl azides into the corresponding amines using trisodium thiophosphate is presented. Thiophosphate is converted into phosphate during these formal reduction processes.

2011-01-01

415

Biaryl synthesis via Pd-catalyzed decarboxylative coupling of aromatic carboxylates with aryl halides.  

Science.gov (United States)

A new strategy for the regiospecific construction of unsymmetrical biaryls is presented, in which easily available salts of carboxylic acids are decarboxylated in situ to give arylmetal species that serve as the nucleophilic component in a catalytic cross-coupling reaction with aryl halides. The catalyst system consists of a copper phenanthroline complex that mediates the extrusion of CO2 from aromatic carboxylates to generate arylcopper species, and a palladium complex that catalyzes the cross-coupling of these intermediates with aryl halides. This bimetallic system allows the direct coupling of various aryl, heteroaryl, or vinyl carboxylic acids with aryl or heteroaryl iodides, bromides, or chlorides at 160 degrees C in the presence of a mild base such as potassium carbonate. The present scope and potential economic impact of the reaction are demonstrated by the synthesis of 42 biaryls, some of which are of substantial industrial relevance. Remaining challenges and future perspectives of the new transformation are discussed. PMID:17375927

Goossen, Lukas J; Rodrguez, Nuria; Melzer, Bettina; Linder, Christophe; Deng, Guojun; Levy, Laura M

2007-04-18

416

Site-selective modification of peptides using rhodium and palladium catalysis: complementary electrophilic and nucleophilic arylation.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The site-selective modification of peptides containing dehydroalanine, tyrosine and tryptophan residues has been achieved using rhodium catalysed conjugate additions or palladium catalysed aryl-amination and -etherification reactions.

Chapman, Cj; Matsuno, A.; Frost, Cg; Willis, Mc

2007-01-01

417

Portuguese compounds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article presents an overview of compounding in Portuguese. Conceived as a plurilexematic unit used as a holistic denomination, a compound is characterized by lexical atomicity. The compound classes continuum we propose is based on the morpho-lexical nature of the internal units (root, word) and on the (non) conformity of compound constructions with Portuguese syntactic templates. Since Portuguese compounds constitute a heterogeneous and bordering class, this analysis al...

Rio-torto, Grac?a; Ribeiro, Si?lvia

2012-01-01

418

Transition-metal-free arylations via photogenerated triplet 4-alkyl- and 4-trimethylsilylphenyl cations.  

Science.gov (United States)

The irradiation in protic solvents of 4-chloroalkylbenzenes and 4-chlorophenyltrimethylsilane caused the heterolytic cleavage of aryl-chlorine bonds to give the corresponding triplet phenyl cations. These were exploited for transition-metal-free arylation reactions under mild conditions to give allylbenzenes, ?-benzyl lactones, 3-arylacetals (ketals), and biaryls in moderate to good yields. The path followed was supported by DFT calculations at the UB3LYP/6-311+G(2d,p) level. PMID:23688128

Qrareya, Hisham; Raviola, Carlotta; Protti, Stefano; Fagnoni, Maurizio; Albini, Angelo

2013-06-21

419

A mild procedure for ?,?-dichlorination of cyclic aryl ketones using commercial bleach  

International Nuclear Information System (INIS)

?,?-Dichloro-cyclic aryl ketones were obtained treating a methanolic solution of the corresponding ketone with commercial bleach at ambient conditions in yields varying from 61 to 92%. Electron-donating and -withdrawing groups in the starting ketone are tolerated but the reaction appears to be sensitive to steric effects. Moreover, five-, six-, and seven-membered aryl-cycloalkanones can be used as substrate. (author)

2007-01-01

420

A mild procedure for {alpha},{alpha}-dichlorination of cyclic aryl ketones using commercial bleach  

Energy Technology Data Exchange (ETDEWEB)

{alpha},{alpha}-Dichloro-cyclic aryl ketones were obtained treating a methanolic solution of the corresponding ketone with commercial bleach at ambient conditions in yields varying from 61 to 92%. Electron-donating and -withdrawing groups in the starting ketone are tolerated but the reaction appears to be sensitive to steric effects. Moreover, five-, six-, and seven-membered aryl-cycloalkanones can be used as substrate. (author)

Quintiliano, Samir A.P.; Silva Junior, Luiz F. [Universidade de Sao Paulo, SP (Brazil). Inst. de Quimica]. E-mail: luizfsjr@iq.usp.br

2007-07-01

 
 
 
 
421

An enantioselective synthesis of 2-aryl cycloalkanones by Sc-catalyzed carbon insertion.  

Science.gov (United States)

Current methods for asymmetric ?-arylation require blocking groups to prevent reaction at the ?'-carbon, basic conditions that promote racemization, or multistep synthesis. This work records the first catalytic enantioselective examples of the diazoalkane-carbonyl homologation reaction. Medium ring 2-aryl ketones are prepared in one step in up to 98:2 er and 99% yield from the unsubstituted lower homologue by Sc-catalyzed aryldiazomethyl insertion with simple bis- and tris(oxazoline) ligands. PMID:21401070

Rendina, Victor L; Moebius, David C; Kingsbury, Jason S

2011-04-15

422

An Improved System for the Palladium-Catalyzed Borylation of Aryl Halides with Pinacol Borane  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A highly efficient method for the palladium-catalyzed borylation of aryl halides with an inexpensive and atom-economical boron source, pinacol borane, has been developed. This system allows for the conversion of aryl and heteroaryl iodides, bromides and several chlorides, containing a variety of functional groups, to the corresponding pinacol boronate esters. In addition to the increase in substrate scope, this is the first general method where relatively low quantities of catalyst and short ...

2008-01-01

423

Synthesis of 5,5-Disubstituted Butenolides Based on a Pd-Catalyzed ?-Arylation Strategy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Methods for the construction of quaternary carbon centers are of great interest to synthetic chemists due to their presence in natural products. Development of the Pd-catalyzed arylation of butenolides with high selectivity for the ?-position allows for a facile construction of quaternary centers. The preparation of a wide variety of ?-aryl butenolides containing a number of functional groups is outlined. An application of this chemistry for a one-pot synthesis of a tricyclic tetrahydroisoq...

Hyde, Alan M.; Buchwald, Stephen Leffler

2009-01-01

424

PEGylated Polyamidoamine Dendrimers with Bis-Aryl Hydrazone Linkages for Enhanced Gene Delivery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Surface modification of polyamidoamine (PAMAM) dendrimers with polyethylene glycol (PEG) often results in the decrease in their buffering capacity, which is essential for gene transfer. In this work, bis-aryl hydrazone bond, which possesses protonatable pyridine and amines, was explored as a new linkage for PEGylation of PAMAM dendrimers. PEGylated polyamidoamine (PAMAM) dendrimer G4.0 conjugates with bis-aryl hydrazone (BAH) linkages were synthesized following a two-step procedure: activatio...

2010-01-01

425

Synthesis and preliminary evaluation of antinociceptive activity of novel isoxazolyl-aryl-hydrazones  

International Nuclear Information System (INIS)

New 2-isoxazoline aldehydes were synthesized, in good yields, from cycloadduct of the 1,3-dipolar cycloaddition reaction between endocyclic enecarbamate and carboethoxyformonitrile oxide (CEFNO). Condensation of these 2-isoxazoline aldehydes with several phenyl-hydrazines produced new isoxazolyl-aryl-hydrazones, which showed low toxicity and excellent antinociceptive activity, when compared to dipyrone. The antinociceptive activity of isoxazolyl-aryl-hydrazones was performed using the acetic acid-induced mice abdominal constrictions test. (author)

2011-01-01

426

Deproto-metallation using a mixed lithium-zinc base and computed CH acidity of 1-aryl 1H-benzotriazoles and 1-aryl 1H-indazoles.  

Science.gov (United States)

1-Aryl-1H-benzotriazoles and -1H-indazoles were synthesized, and their deproto-metallation using the base prepared by mixing LiTMP with ZnCl2TMEDA (1/3 equiv.) was studied. In the indazole series, reactions occurring at the 3 position were followed by ring opening, and functionalization of the substrate was only found possible (on the sulfur ring) using 2-thienyl as aryl group. In the benzotriazole series, either mono- or bis-deprotonation (depending on the amount of base employed) was achieved with phenyl, 4-methoxyphenyl and 2-thienyl as aryl group, and bis-deprotonation in the case of 4-chlorophenyl and 4-trifluoromethylphenyl. The experimental results were analyzed with the help of the CH acidities of the substrates, determined in THF solution using the DFT B3LYP method. PMID:24445663

Nagaradja, Elisabeth; Chevallier, Floris; Roisnel, Thierry; Dorcet, Vincent; Halauko, Yury S; Ivashkevich, Oleg A; Matulis, Vadim E; Mongin, Florence

2014-03-01

427

Design, synthesis and pharmacological screening of a series of N1-(substituted) aryl-5,7-dimethyl-2-(substituted)pyrido(2,3-d)-pyrimidin-4(3H)-ones as potential histamine H1-receptor antagonists.  

Science.gov (United States)

A series of N1-(substituted)aryl-5,7-dimethyl-2-(substituted)pyrido(2,3-d)pyrimidin-4(3H)-one was designed on the basis of the triangular pharmacophoric requirement of histamine H1-receptor antagonists. The designed series was synthesized by cyclo-condensation of monoaryl thiourea with ethyl cyanoacetate in the presence of dry HCl gas to give N1-(substituted aryl)-2-mercaptopyrimidine-4(3H)-one, which on cyclo-condensation with acetylacetone gave the pyridopyrimidinone. Further methylation of the mercapto group at C-2 with methyl iodide followed by nucleophilic displacement of the methylmercapto group by various amines gave the targeted compounds. All the synthesized compounds were screened for histamine H1-receptor antagonistic activity by the in vitro method of inhibition of the isotonic contraction induced by histamine on isolated guinea pig ileum using cetirizine as a standard drug. All the compounds exhibited potent histamine H1-receptor antagonistic activity with pA2 values from 7.30- 9.75 (cetirizine, pA2 value 9.40). The potent compounds were screened for their in vivo antihistaminic activity by protection of animal from asphyxic shock. The sedative potential of potent compounds was checked on albino mice by photoactometer and they had comparative sedative potential to the standard drug cetirizine. None of the compound exhibited anticholinergic activity in the in vitro rat ileum model. PMID:17252940

Suhagia, Bhanubhai N; Chhabria, Mahesh T; Makwana, Ashlesha G

2006-12-01

428

SYNTHESIS AND BIOLOGICAL ACTIVITIES OF 2-(FUROYL AMINO)-5- (SUBSTITUTED ARYL)-1,3,4-THIADIAZOLE AND 2-(SUBSTITUTED BENZOYL AMINO)-5-(FURYL)-1,3,4-THIADIAZOLE Synthese und biologische AKTIVITTEN VON 2 - (Furoyl AMINO) -5 - (Substituiertem Aryl)-1,3,4-thiadiazol und 2 -(substituiertes Benzoyl AMINO)-5 -(FURYL)-1,3,4-THIADIAZOLE  

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1-(substituted aroyl)-4-furoyl- thiosemicarbazides 3(a-e) / 1-furoyl-4-(substituted benzoyl)-thiosemicarbazides 7(a-f) are synthesized under phase transfer catalysis, which on cyclisation with perchloric acid in acetic anhydride furnish perchloric acid salt of 2- (furoylamino)-5-(substituted aryl)-1,3,4-thiadiazoles 4(a-e)/ 2-(substituted benzoylamino)-5- (furyl)-1,3,4-thiadiazoles 8(a-f) respectively. The sulphur and nitrogen containing compounds were screened for anti-microbial activity sho...

Parmar, Vijay V. Dabholkar And Bharat M.

2011-01-01

429

ULTRASOUND ASSISTED EFFICIENT AND GREENER ONE POT SYNTHESIS OF ARYL-14-H-DIBENZO [a,j]XANTHENE DERIVATIVES Ultraschall untersttzt effizientere und umweltfreundlichere ONE Eintopfsynthese ARYL-14-H-dibenzo [a, j] Xanthenderivate  

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Aryl-14-H-dibenzo[a,j]xanthenes have been synthesized in high yields from the condensation of aryl aldehydes and 2-napthol in presence of copper perchlorate hexahydrate as catalyst at room temperature gives aryl-14-H-dibenzo[a,j]xanthenes with excellent yields under ultrasound irradiation (35 kHz). This method has the advantages of high yield, simple methodology, greener and one pot procedure.

Saurabh Puri, Balbir Kaur

2011-01-01

430

ULTRASOUND ASSISTED EFFICIENT AND GREENER ONE POT SYNTHESIS OF ARYL-14-H-DIBENZO [a,j]XANTHENE DERIVATIVES Ultraschall untersttzt effizientere und umweltfreundlichere ONE Eintopfsynthese ARYL-14-H-dibenzo [a, j] Xanthenderivate  

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Full Text Available Aryl-14-H-dibenzo[a,j]xanthenes have been synthesized in high yields from the condensation of aryl aldehydes and 2-napthol in presence of copper perchlorate hexahydrate as catalyst at room temperature gives aryl-14-H-dibenzo[a,j]xanthenes with excellent yields under ultrasound irradiation (35 kHz. This method has the advantages of high yield, simple methodology, greener and one pot procedure.

Saurabh Puri, Balbir Kaur, Anupama Parmar and Harish Kumar

2011-07-01

431

Oxidative Aromatization, Cytotoxic Activity Evaluation and Conformational Study of Novel 7-aryl-10, 11-dihydro-7H-chromeno [4, 3-b]quinoline-6, 8(9H, 12H)-dione Derivatives.  

Science.gov (United States)

In the present work, novel 7-aryl-10, 11-dihydro-7H-chromeno [4, 3-b]quinoline-6, 8(9H, 12H)-dione derivatives were synthesized by oxidation of 7-aryl-8, 9, 10, 12-tetrahydro-7H-chromeno[4, 3-b]quinoline-6, 8-diones in the presence of silica sulfuric acid/NaNO2 with yields of 64-74%. Cytotoxic activity of synthesized compounds was assessed on three different human cancer cell lines (K562, LS180, and MCF-7). Synthesized compounds showed moderate cytotoxic activities. The most active one apeared to be 2e, containing a methoxy group on the meta position of phenyl ring (IC50 range in different cell lines: 11.1-55.7 M). Furthermore; comparison of the cytotoxic activity of these novel oxidized derivatives with non-oxidized counterparts revealed that oxidation of dihydropyridine ring to pyridine, improves the activity especially in LS180 cell line. Conformational analysis revealed that some conformational aspects of oxidized derivatives such as orientation of C7-aryl substitute were clearly different from non-oxidized ones. PMID:24734061

Motamedi, Radineh; Shafiee, Abbas; Rezai, Mohammad Reza; Firuzi, Omidreza; Edraki, Najmeh; Miri, Ramin

2014-01-01

432

An LFER study of the protolytic equilibria of 4-aryl-2,4-dioxobutanoic acids in aqueous solutions  

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Full Text Available The protolytic equilibria of 13 4-aryl-2,4-dioxobutanoic acids (ADKs were spectrophotometrically studied in aqueous solutions in the pH range 19 at 251 C and an ionic strength of 0.1 mol l-1 (NaCl, with the exception of the 4-OH- derivative which was also potentiometrically studied in the pH range 710 at 251 C and an ionic strength of 0.1 mol l-1 (NaCl. In solution, the compounds simultaneously exist in one diketo and two enolic forms; therefore, the determined acidity constants (pKa1 1.872.29, pKa2 6.638.13 and pKa3(4-OH- 9.52 represent system macro constants. The 1H-NMR spectrum of the basic compound (4-phenyl-2,4-dioxobutanoic acid (25 C, pD 5.0 proved the existence of all tautomeric forms. Using the extended Hammett relation, the determined pKa values were correlated with literature ? values. The predicted pKa values were in fair accordance with the experimentally observed ones. Molecular, monoanionic and dianionic forms of the basic compound were optimized by the semi-empirical molecular orbital PM6 method using the implicit water solvation model (COSMO. The obtained geometries were used to explain the quality of the LFER models.

TATJANA Z. VERBIC

2007-12-01

433

3-Aryl-2-[1H-benzotriazol-1-yl]acrylonitriles: a novel class of potent tubulin inhibitors.  

Science.gov (United States)

During a screening for compounds that could act against Mycobacterium tuberculosis, a series of new cellular antiproliferative agents was identified. The most cytotoxic molecules were evaluated against a panel of human cell lines derived from hematological and solid human tumors. In particular, (E)-2-(1H-benzo[d] [1,2,3]triazol-1-yl)-3-(4-methoxyphenyl)acrylonitrile (1) was found to be of a potency comparable to etoposide and greater than 6-mercaptopurine in all cell lines tested. Accordingly, a synthesis of a new series of (E)-2-(5,6-dichloro-1H-benzo[d] [1,2,3]triazol-1-yl)-3-(4-R-phenyl)acrylonitriles was conducted in order to extend the studies of structure-activity relationship (SAR) for this class of molecules. With the aim to evaluate if 3-aryl-2-[1H-benzotriazol-1-yl]acrylonitriles were able to act like tubulin binding agents, the effects on cell cycle distribution of the most active compounds (1, 2a, 3 and 4) were analyzed in K562 cells. A detailed molecular modeling study of the putative binding mode of this series of compounds on tubulin is also reported. PMID:21741130

Carta, Antonio; Briguglio, Irene; Piras, Sandra; Boatto, Giampiero; La Colla, Paolo; Loddo, Roberta; Tolomeo, Manlio; Grimaudo, Stefania; Di Cristina, Antonietta; Pipitone, Rosaria Maria; Laurini, Erik; Paneni, Maria Silvia; Posocco, Paola; Fermeglia, Maurizio; Pricl, Sabrina

2011-09-01

434

[Studies on reaction and antibacterial activity of 1-aryl-4-ethoxycarbonyl-5-amino-1,2,3-triazole with several electrophilic reagents].  

Science.gov (United States)

Upon treatment of 1-aryl-4-ethoxycarbonyl-5-amino-1,2,3-triazoles (1) with excess acetic acid, acetic anhydride, acetyl chloride, benzoyl chloride, formamide, etc., fourteen new derivatives of 1 were obtained in good yields, such as, 1-H-4-ethoxycarbonyl-5-arylamino-1,2,3-triazoles (2b-d), 1-RCO-4-ethoxycarbonyl-5-arylamino-1,2,3-triazoles (3a-d), 1-aryl-4-ethoxycarbonyl-5-acetylamino-1,2,3-triazoles (4a-d) and 1-formoyl-4-ethoxycarbonyl-5-p-nitrophenylamino-1,2,3-triazole (5a), 1-benzoyl-4-ethoxycarbonyl-5-p-nitrophenylamino-1,2,3-triazoles (5b), 1-p-chlorobenzoyl-4-ethoxycarbonyl-5-p-nitrophenylamino-1,2,3-triazoles (5c). Some of them were rearrangement products. Structures of all heterocyclic compounds were identified by elemental analyses, IR, 1HNMR and MS. Inhibiting effects of some compounds on B. substilis, E. coli, E. aerogenes and S. aureus were also screened. PMID:1823974

Zhang, Z Y; Liu, Y; Zheng, G Y; Chen, M Q; Yang, S Y

1991-01-01

435

(Z)-1-Aryl-3-arylamino-2-propen-1-ones, Highly Active Stimulators of Tubulin Polymerization: Synthesis, Structure Activity Relationship (SAR), Tubulin Polymerization and Cell Growth Inhibition Studies  

Science.gov (United States)

Tubulin, the major structural component of microtubules, is a target for the development of anticancer agents. A series of (Z)-1-Aryl-3-arylamino-2-propen-1-one (10) were synthesized and evaluated for anti-proliferative activity in cell based assay. The most active compound (Z)-1-(2- bromo-3,4,5-trimethoxyphenyl)-3-(3-hydroxy-4-methoxyphenylamino)-prop-2-en-1-one (10ae) was tested in 20 tumor cell lines including multidrug resistant phenotype and was found to induce apoptosis in all these cell lines with similar GI50 values. Flow cytometry studies showed that 10ae arrested the cells in G2/M phase of cell cycle. In addition to G2/M block, these compounds caused microtubule stabilization like paclitaxel and induced apoptosis via activation of the caspase family. The observations made in this investigation demonstrate that (Z)-1-Aryl-3- arylamino-2-propen-1-one (10) represents a new class of microtubule stabilizing agents.

Reddy, M.V. Ramana; Akula, Balaiah; Cosenza, Stephen C; Lee, Clement M; Mallireddigari, Muralidhar R; Pallela, Venkat R; Subbaiah, DRC Venkata; Udofa, Andrew; Reddy, E. Premkumar

2012-01-01

436

Synthesis and biological evaluation of 3-aryl-quinoxaline-2-carbonitrile 1,4-di-N-oxide derivatives as hypoxic selective anti-tumor agents.  

Science.gov (United States)

A series of 3-aryl-2-quinoxaline-carbonitrile 1,4-di-N-oxide derivatives were designed, synthesized and evaluated for hypoxic and normoxic cytotoxic activity against human SMMC-7721, K562, KB, A549 and PC-3 cell lines. Many of these new compounds displayed more potent hypoxic cytotoxic activity compared with TX-402 and TPZ in the tumor cells based evaluation, which confirmed our hypothesis that the replacement of the 3-amine with the substituted aryl ring of TX-402 increases the hypoxic anti-tumor activity. The preliminary SAR revealed that 3-chloro was a favorable substituent in the phenyl ring for hypoxic cytotoxicity and 7-methyl or 7-methoxy substituted derivatives exhibited better hypoxic selectivity against most of the tested cell lines. The most potent compound, 7-methyl-3-(3-chlorophenyl)-quinoxaline-2-carbonitrile 1,4-dioxide (9h) was selected for further anti-tumor evaluation and mechanistic study. It also exhibited significant cytotoxic activity against BEL-7402, HepG2, HL-60, NCI-H460, HCT-116 and CHP126 cell lines in hypoxia with IC?? values ranging from 0.31 to 3.16 ?M, and preliminary mechanism study revealed that 9h induced apoptosis in a caspase-dependent pathway. PMID:22890172

Hu, Yunzhen; Xia, Qing; Shangguan, Shihao; Liu, Xiaowen; Hu, Yongzhou; Sheng, Rong

2012-01-01

437

Synthesis and Biological Evaluation of 3-Aryl-quinoxaline-2-carbonitrile 1,4-Di-N-oxide Derivatives as Hypoxic Selective Anti-tumor Agents  

Directory of Open Access Journals (Sweden)

Full Text Available A series of 3-aryl-2-quinoxaline-carbonitrile 1,4-di-N-oxide derivatives were designed, synthesized and evaluated for hypoxic and normoxic cytotoxic activity against human SMMC-7721, K562, KB, A549 and PC-3 cell lines. Many of these new compounds displayed more potent hypoxic cytotoxic activity compared with TX-402 and TPZ in the tumor cells based evaluation, which confirmed our hypothesis that the replacement of the 3-amine with the substituted aryl ring of TX-402 increases the hypoxic anti-tumor activity. The preliminary SAR revealed that 3-chloro was a favorable substituent in the phenyl ring for hypoxic cytotoxicity and 7-methyl or 7-methoxy substituted derivatives exhibited better hypoxic selectivity against most of the tested cell lines. The most potent compound, 7-methyl-3-(3-chlorophenyl-quinoxaline-2-carbonitrile 1,4-dioxide (9h was selected for further anti-tumor evaluation and mechanistic study. It also exhibited significant cytotoxic activity against BEL-7402, HepG2, HL-60, NCI-H460, HCT-116 and CHP126 cell lines in hypoxia with IC50 values ranging from 0.31 to 3.16 ?M, and preliminary mechanism study revealed that 9h induced apoptosis in a caspase-dependent pathway.

Yongzhou Hu

2012-08-01

438

Biological evaluation and structure-activity relationships of bis-(3-aryl-3-oxo-propyl)-methylamine hydrochlorides and 4-aryl-3-arylcarbonyl-1-methyl-4-piperidinol hydrochlorides as potential cytotoxic agents and their alkylating ability towards cellular glutathione in human leukemic T cells.  

Science.gov (United States)

Various bis (3-aryl-3-oxo-propyl)methylamine hydrochlorides 1 and their corresponding structural and non-classical isomers 4-aryl-3-arylcarbonyl-1-methyl-4-piperidinols 3 were evaluated against human leukemic T (Jurkat) cells and found to possess significant cytotoxicity. Among the series 1 (bis-Mannich bases) and 3 (corresponding piperidinols), compounds la, 1c and 1e showed cytotoxic potency which was approximately 1.6, 3.7 and 3.4 times that of the reference drug 5-fluorouracil, respectively. Except for compound 1d, conversion of bis-Mannich bases to their corresponding piperidinols 3a, 3b and 3e lowered the potency. Besides chloro derivative 1d, bis-Mannich bases displayed greater cytotoxicity compared with their mono-Mannich bases, series 5. Representative bis-Mannich bases (1a, 1e) and piperidinols (3a, 3e) decreased the glutathione level of Jurkat cells. Molecular modeling was utilized in order to evaluate whether the shape, size, critical volume, solvent accessible area and partition coefficient of the different compounds had contributed to the varying potencies observed. Bis-Mannich bases 1a, 1c and 1e may serve as candidate anticancer agents for future development. PMID:16032973

Gul, Mustafa; Gul, Halise Inci; Das, Umashankar; Hanninen, Osmo

2005-01-01

439

Synthesis, Structure and Antifungal Activity of New 3-[(5-Aryl-1,3,4-oxadiazol-2-yl)methyl]benzo[d]thiazol-2(3H)-ones  

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A series of new 3-[(5-aryl-1,3,4-oxadiazol-2-yl)methy])benzo[d]thiazol-2(3H)-ones were synthesized by reaction of (5-substituted-2-oxobenzothiazolin-3-yl)-acetohydrazide with various aromatic acids in POCl3 under reflux conditions. The structures of the title compounds were confirmed by 1H-NMR, 13C-NMR, IR, MS and elemental analysis. Furthermore, the structure of compound 4i was determined by single-crystal X-ray diffraction. The preliminary bioassy results indicated that some of them showed ...

Jian-Quan Weng; Xing-Hai Liu; Hua Huang; Cheng-Xia Tan; Jie Chen

2012-01-01

440

Synthesis of aryl b-N-acetylglucosamine desmodified at C-6 as potential antimicrobial agents; Sintese de b-N-acetilglicosaminideos de arila modificados em C-6 como potenciais agentes antimicrobianos  

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We report herein the synthesis of aryl beta-N-acetylglucosaminides containing azido, amino and acetamido groups at C-6 as potential antimicrobial agents. It was expected that these compounds could interfere with the biosynthesis and/or biotransformation of Nacetylglucosamine in fungi and bacteria. None of the compounds showed antimicrobial activity against bacteria (Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa), filamentous fungus (Aspergillus niger) and yeasts (Saccharomyces cerevisae, Candida albicans and Candida tropicallis), at the concentration of 1 mg/mL in agar diffusion assay. (author)

Manfrini, Rozangela Magalhaes; Souza Filho, Jose Dias de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Inst. de Ciencias Exatas; Figueireido, Rute Cunha; D' Angelis, Allison Fabiano; Prado, Maria Auxiliadora Fontes; Nunan, Elziria de Aguiar; Martins, Gabriela Aires; Alves, Ricardo Jose [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Faculdade de Farmacia. Dept. de Produtos Farmaceuticos]. E-mail: ricardodylan@farmacia.ufmg.br

2008-07-01

 
 
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