WorldWideScience
1

Characterization and expression of hepatic sulfotransferase involved in the metabolism of N-substituted aryl compounds.  

OpenAIRE

An aryl sulfotransferase, whose cDNA was isolated from the rat liver library, was found to catalyze bioactivation of minoxidil through N-O-sulfation and N-sulfation of a carcinogenic heterocyclic amine, IQ, by expression in COS-1 cells. cDNA of a human ortholog also was isolated and characterized as a major minoxidil-activating enzyme in human liver. Another group of aryl sulfotransferases catalyzing O-sulfation of carcinogenic N-hydroxyarylamines was separated from livers of rats and humans....

Yamazoe, Y.; Ozawa, S.; Nagata, K.; Gong, D. W.; Kato, R.

1994-01-01

2

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

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.)

4

Photolytic inhibition and labeling of proteins with aryl diazonium compounds  

International Nuclear Information System (INIS)

In the course of preparing aryl azide derivatives for use as photoprobes, we have observed significant light sensitivity in the precursor aryl diazonium compounds. The photosensitive properties of this class of compounds are of interest since they will seek out cationic binding sites in biological targets, and can be employed to inhibit complementary targets at acid pH. The relationship between photolytic change in the structure of diazonium compounds and the corresponding change in function of a biological target are presented. Experiments are described in which the dark and light sensitive properties of a model diazonium compound, diazobenzene sulfonate (DBS), were determined. The ultraviolet spectra were used to evaluate the dark stability and light sensitivity og DBS. Chymotrypsin and trypsin served as functioning targets for further evaluation of the photochemical properties. Both enzymes are stable to the probe in the dark at acid pH. A rapid loss of enzyme activity was observed following flash photolysis of DBS-enzyme solutions. Photolytic incorporation of radioactive DBS into chymotrypsin was observed. Aryl diazonium salts can be employed to probe the availability of complementary sites in biological targets at different acid pH values. (Author)

5

N-aryl-2-aminobenzimidazoles: novel, efficacious, antimalarial lead compounds.  

Science.gov (United States)

From the phenotypic screening of the AstraZeneca corporate compound collection, N-aryl-2-aminobenzimidazoles have emerged as novel hits against the asexual blood stage of Plasmodium falciparum (Pf). Medicinal chemistry optimization of the potency against Pf and ADME properties resulted in the identification of 12 as a lead molecule. Compound 12 was efficacious in the P. berghei (Pb) model of malaria. This compound displayed an excellent pharmacokinetic profile with a long half-life (19 h) in rat blood. This profile led to an extended survival of animals for over 30 days following a dose of 50 mg/kg in the Pb malaria model. Compound 12 retains its potency against a panel of Pf isolates with known mechanisms of resistance. The fast killing observed in the in vitro parasite reduction ratio (PRR) assay coupled with the extended survival highlights the promise of this novel chemical class for the treatment of malaria. PMID:25007124

Ramachandran, Sreekanth; Hameed P, Shahul; Srivastava, Abhishek; Shanbhag, Gajanan; Morayya, Sapna; Rautela, Nikhil; Awasthy, Disha; Kavanagh, Stefan; Bharath, Sowmya; Reddy, Jitendar; Panduga, Vijender; Prabhakar, K R; Saralaya, Ramanatha; Nanduri, Robert; Raichurkar, Anandkumar; Menasinakai, Sreenivasaiah; Achar, Vijayashree; Jimnez-Daz, Mara Beln; Martnez, Mara Santos; Angulo-Barturen, Iigo; Ferrer, Santiago; Sanz, Laura Mara; Gamo, Francisco Javier; Duffy, Sandra; Avery, Vicky M; Waterson, David; Lee, Marcus C S; Coburn-Flynn, Olivia; Fidock, David A; Iyer, Pravin S; Narayanan, Shridhar; Hosagrahara, Vinayak; Sambandamurthy, Vasan K

2014-08-14

6

A selective palladium-catalyzed carbonylative arylation of aryl ketones to give vinylbenzoate compounds.  

Science.gov (United States)

Preparation of enols: when treated with [{Pd(cinnamyl)Cl}(2)]/cataCXium A (nBuPAd(2), Ad=adamantyl) under an atmosphere of CO, aryl ketones react with aryl halides in a carbonylative C-O coupling reaction to form (Z)-vinyl benzoates. PMID:23143936

Schranck, Johannes; Tlili, Anis; Neumann, Helfried; Alsabeh, Pamela G; Stradiotto, Mark; Beller, Matthias

2012-12-01

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Electrolytic partial fluorination of organic compounds. 83. Anodic fluorination of N-substituted pyrroles and its synthetic applications to gem-difluorinated heterocyclic compounds.  

Science.gov (United States)

Anodic fluorination of N-substituted pyrroles was carried out in MeCN containing supporting fluoride salts such as Et3N-nHF (n = 2-5) and Et4NF-4HF with use of platinum electrodes under constant current conditions. Anodic fluorination of N-methyl- and N-p-tosylpyrroles having an electron-withdrawing cyano group proceeded smoothly to provide the corresponding fluorinated products in moderate to excellent yields, while anodic fluorination of N-methylpyrrole devoid of an electron-withdrawing cyano group did not take place and a polymeric product was formed at the anode surface. In sharp contrast to the cases of N-methylpyrroles, even N-p-tosylpyrrole devoid of an electron-withdrawing cyano group underwent anodic fluorination efficiently. Diels-Alder reaction of 5,5-difluoro-1-methyl-3-pyrrolin-2-one (2e) derived from anodic fluorination of 2-cyano-1-methylpyrrole (2a) with various dienes was carried out to provide the cycloaddition products in excellent yields. Furthermore, Michael reaction of 2e with various nucleophiles was also successfully carried out to provide the Michael addition products in good to excellent yields. PMID:16468791

Tajima, Toshiki; Nakajima, Atsushi; Fuchigami, Toshio

2006-02-17

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Radiobromination of aromatic compounds by cleavage of aryl-tin bonds  

International Nuclear Information System (INIS)

Radiobrominated (sup(77,82)Br) aromatic compounds were synthesized by the cleavage of aryl-tin derivatives with oxidized low specific activity 82Br or no-carrier-added (NCA) [77Br]bromide. Both chloramine-T and N-chlorosuccinimide, when used as oxidants, gave near quantitative yields within 5 min. (author)

9

Antitumor agents. 141. Synthesis and biological evaluation of novel thiocolchicine analogs: N-acyl-, N-aroyl-, and N-(substituted benzyl)deacetylthiocolchicines as potent cytotoxic and antimitotic compounds.  

Science.gov (United States)

Three series of novel thiocolchicine analogs, N-acyl-, N-aroyl-, and N-(substituted benzyl)-deacetylthiocolchicinoids, have been synthesized and evaluated for their cytotoxicity against various tumor cell lines, especially solid tumor cell lines, and for their inhibitory effects on tubulin polymerization in vitro. Most of these compounds showed strong inhibitory effects on tubulin polymerization comparable to that obtained with thiocolchicine and greater than that obtained with colchicine. Only compounds with a long side chain at the C(7) position, such as 22-24, did not inhibit tubulin polymerization. Several of the active N-aroyldeacetylthiocolchicine analogs had positive optical rotations, in contrast to the negative optical rotation observed with most colchicinoids. This property might be attributed to a reversal of biaryl configuration from the normal aS to aR. Therefore, the N-aroyl analogs were further evaluated by circular dichroism, which readily distinguishes between the aS and aR biaryl configurations. This latter technique demonstrated that the active N-aroyl analogs do have an aS configuration despite their positive optical rotations. However, comparison of 1H NMR and UV spectral data of N-(substituted benzyl)-deacetylthiocolchicines with those of corresponding N-aroyldeacetylthiocolchicines suggested a different biaryl dihedral angle [even though these compounds have the same aS biaryl configuration]. The similar tubulin binding properties of these compounds suggest that a biaryl dihedral angle of 53 degrees is not essential for colchicinoid-tubulin interaction. The increased cytotoxicity of N-(substituted benzyl)deacetylthiocolchicines compared to the N-aroyldeacetylthiocolchicines may be attributed to different lipophilicity, drug uptake, or drug metabolism in the tumor cells. The side chain at the C(7) position affects inhibition of tubulin polymerization and the cytotoxic activity of colchicinoids as a function of its size and its contribution to lipophilicity. PMID:8496915

Sun, L; Hamel, E; Lin, C M; Hastie, S B; Pyluck, A; Lee, K H

1993-05-14

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Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds  

Directory of Open Access Journals (Sweden)

Full Text Available N-Arylated aliphatic and aromatic amines are important substituents in many biologically active compounds. In the last few years, transition-metal-mediated N-aryl bond formation has become a standard procedure for the introduction of amines into aromatic systems. While N-arylation of simple aromatic halides by simple amines works with many of the described methods in high yield, the reactions may require detailed optimization if applied to the synthesis of complex molecules with additional functional groups, such as natural products or drugs. We discuss and compare in this review the three main N-arylation methods in their application to the synthesis of biologically active compounds: Palladium-catalysed BuchwaldHartwig-type reactions, copper-mediated Ullmann-type and ChanLam-type N-arylation reactions. The discussed examples show that palladium-catalysed reactions are favoured for large-scale applications and tolerate sterically demanding substituents on the coupling partners better than ChanLam reactions. ChanLam N-arylations are particularly mild and do not require additional ligands, which facilitates the work-up. However, reaction times can be very long. Ullmann- and BuchwaldHartwig-type methods have been used in intramolecular reactions, giving access to complex ring structures. All three N-arylation methods have specific advantages and disadvantages that should be considered when selecting the reaction conditions for a desired CN bond formation in the course of a total synthesis or drug synthesis.

Burkhard Koenig

2011-01-01

11

Preparing poly(aryl ethers) using alkaline earth metal carbonates, organic acid salts, and optionally copper compounds, as catalysts  

International Nuclear Information System (INIS)

This patent describes an improved process for preparing poly(aryl ethers) and poly(aryl ether ketones) by the reaction of a mixture of at least one bisphenol and at least one dihalobenzenoid compound, and/or a halophenol. The improvement comprises providing to the reaction, a base which is a combination of an alkaline earth metal carbonate and/or bicarbonate and a potassium, rubidium, or cesium salt of an organic acid or combination of organic salts thereof

12

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

13

Palladium-catalyzed coupling of tetraorganotin compounds with aryl and benzyl halides. Synthetic utility and mechanism  

International Nuclear Information System (INIS)

Palladium complexes catalyze the coupling of tetraorganotin compounds with benzyl and aryl halides, benzylchlorobis(triphenylphosphine)palladium(II) (1) being the catalyst of choice. Various functional groups are tolerated by this reaction and generally high yields of the cross-coupled products are obtained. Oxygen has a considerable accelerating effect on the reaction, whereas triphenylphosphine has little effect. The reaction of substituted bromobenzenes with tetramethyltin catalyzed by 1 is accelerated by electron-withdrawing groups; however, a simple Hammett correlation is not observed. Optically active ?-deuteriobenzyl bromide reacts with tetramethyltin to afford optically active ?-deuterioethylbenzene with inversion of configuration. Homocoupling is the main reaction observed when lithium or Grignard reagents react with benzyl chloride under the influence of various palladium catalysts

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

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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

15

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

OpenAIRE

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.

Urbina, J.; Palma, A.; La?a?pez, S.; Devia, C.; Enriz, R.; Zacchino, S.; Kouznetsov, V.

2000-01-01

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Arylation of diorganochalcogen compounds with diaryliodonium triflates: metal catalysts are unnecessary.  

Science.gov (United States)

Diaryliodonium triflates transfer an aryl group to the chalcogen atom of organic sulfides, selenides, and tellurides (but not ethers), in the absence of transition-metal catalyst, simply upon heating in chloroform or dichloroethane solution. PMID:25493925

Racicot, Lanne; Kasahara, Takahito; Ciufolini, Marco A

2014-12-19

17

Alkyl- or arylthiolation of aryl iodide via cleavage of the S-S bond of disulfide compound by nickel catalyst and zinc.  

Science.gov (United States)

Various aryl sulfides can be synthesized by nickel-catalyzed alkyl- or arylthiolation of aryl iodide with a disulfide compound. This reaction produces Ni(0) from NiBr2-bpy by the reduction with zinc, and this generated complex works as an activating species to convert ArI into ArSR under neutral conditions. Furthermore, this system enables the use of two RS groups in (RS)2. PMID:15387621

Taniguchi, Nobukazu

2004-10-01

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Microwave-assisted synthesis and evaluation of antibacterial activity of 2,2'-(naph- thalene-2,7-diylbis(oxybis(N'-substituted acetohydrazide derivatives  

Directory of Open Access Journals (Sweden)

Full Text Available A series of Schiff base of 2,2'-(naphthalene-2,7-diylbis(oxybis(N'-substituted acetohydrazide (4a-m derivatives has been synthesized by the acid catalyzed condensation of aryl/hetero aromatic aldehydes with 2,2'-(naphthalene-2,7-diylbis(oxydiacetohydrazide (3 under microwave irradiation and conventional method for comparison. The structures of all the newly synthesized compounds have been characterized by IR, 1H NMR, 13C NMR and Mass spectra. All the synthesized compounds have been screened for their in vitro antibacterial activity.DOI: http://dx.doi.org/10.4314/bcse.v26i2.9

A. Sivakumar

2012-08-01

19

Determination of drug-polymer binding constants by affinity capillary electrophoresis for aryl propionic acid derivatives and related compounds.  

Science.gov (United States)

The binding constants (K(b)s) of 17 aryl propionic acid derivatives (APADs) and related compounds with polyvinylpyrrolidone (PVP K30) and vinylpyrrolidone-vinyl acetate copolymer (Kollidon VA64) in aqueous media were determined by affinity capillary electrophoreses (ACE). The K(b)s of APAD to polymers increase with octanol-water partition coefficients of the compounds. Kollidon VA64 is a stronger binder than PVP K30 to APAD compounds. The K(b)s are greater at pH 4 than at pH 9. Both hydrophobic interaction and hydrogen bonding may be involved. However, hydrophobic interaction appears to be dominant. The ACE method is simple and fast, which could be used to study drug-polymer interaction in aqueous media. PMID:23280598

Jia, Zhongjiang; Choi, Duk Soon; Chokshi, Hitesh

2013-03-01

20

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

21

Evaluation of the Toxicity of 5-Aryl-2-Aminoimidazole-Based Biofilm Inhibitors against Eukaryotic Cell Lines, Bone Cells and the Nematode Caenorhabditis elegans  

Directory of Open Access Journals (Sweden)

Full Text Available Previously, we have synthesized several series of compounds based on the 5-aryl-2-aminoimidazole scaffold, which showed a preventive activity against microbial biofilms. We here studied the cytotoxicity of the most active compounds of each series. First, the cytostatic activity was investigated against a number of tumor cell lines (L1210, CEM and HeLa. A subset of monosubstituted 5-aryl-2-aminoimidazoles showed a moderate safety window, with therapeutic indices (TIs ranging between 3 and 20. Whereas introduction of a (cyclo-alkyl chain at the N1-position strongly reduced the TI, introduction of a (cyclo-alkyl chain or a triazole moiety at the 2N-position increased the TI up to 370. Since a promising application of preventive anti-biofilm agents is their use in anti-biofilm coatings for orthopedic implants, their effects on cell viability and functional behavior of human osteoblasts and bone marrow derived mesenchymal stem cells were tested. The 2N-substituted 5-aryl-2-aminoimidazoles consistently showed the lowest toxicity and allowed survival of the bone cells for up to 4 weeks. Moreover they did not negatively affect the osteogenic differentiation potential of the bone cells. Finally, we examined the effect of the compounds on the survival of Caenorhabditis elegans, which confirmed the higher safety window of 2N-substituted 5-aryl-2-aminoimidazoles.

Hans Steenackers

2014-10-01

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Novel N-substituted sophoridinol derivatives as anticancer agents.  

Science.gov (United States)

Using sophoridine (1) as the lead compound, a series of new N-substituted sophoridinic acid derivatives were designed, synthesized and evaluated for their cytotoxicity. SAR analysis indicated that introduction of a chlorobenzyl on the 12-nitrogen atom of sophoridinol might significantly enhance the antiproliferative activity. Of the newly synthesized compounds, sophoridinol analogue 9k exhibited a potent effect against six human tumor cell lines (liver, colon, breast, lung, glioma and nasopharyngeal). The mode of action of 9k was to inhibit the DNA topoisomerase I activity, followed by the G0/G1 phase arrest. It also showed a moderate oral bioavailability and good safety invivo. Therefore, compound 9k has been selected as a novel-scaffold lead for further structural optimizations or as a chemical probe for exploring anticancer pathways of this kinds of compounds. PMID:24826818

Bi, Chong-Wen; Zhang, Cai-Xia; Li, Ying-Hong; Tang, Sheng; Deng, Hong-Bin; Zhao, Wu-Li; Wang, Zhen; Shao, Rong-Guang; Song, Dan-Qing

2014-06-23

23

Magnesium-induced copper-catalyzed synthesis of unsymmetrical diaryl chalcogenide compounds from aryl iodide via cleavage of the Se-Se or S-S bond.  

Science.gov (United States)

The methodology for a copper-catalyzed preparation of diaryl chalcogenide compounds from aryl iodides and diphenyl dichalcogenide molecules is reported. Unsymmetrical diaryl sulfide or diaryl selenide can be synthesized from aryl iodide and PhYYPh (Y = S, Se) with a copper catalyst (CuI or Cu(2)O) and magnesium metal in one pot. This reaction can be carried out under neutral conditions according to an addition of magnesium metal as the reductive reagent. Furthermore, it is efficiently available for two monophenylchalcogenide groups generated from diphenyl dichalcogenide. PMID:14750822

Taniguchi, Nobukazu; Onami, Tetsuo

2004-02-01

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A Regioselective Synthesis of Benzopinacolones through Aerobic Dehydrogenative ?-Arylation of the Tertiary sp(3) C?H Bond of 1,1-Diphenylketones with Aromatic and Heteroaromatic Compounds.  

Science.gov (United States)

A regioselective synthesis of symmetrical and unsymmetrical benzopinacolones through aerobic dehydrogenative ?-arylation at the tertiary sp(3) C?H bond of substituted 1,1-diphenylketones with aromatic and heteroaromatic compounds, in the presence of K2 S2 O8 in CF3 COOH at room temperature, is described. The reaction is proposed to go via a carbocation intermediate, which could be generated directly from cleavage of the sp(3) C?H bond of 1,1-diphenylketone. Subsequent ?-arylation was achieved at the methene sp(3) carbon atom of the substituted ketone. A variety of substituted aromatic and heteroaromatic compounds were compatible with this reaction. In addition, benzopinacolones were converted into sterically hindered, tetrasubstituted alkenes and polycyclic aromatic compounds. PMID:25394565

More, Nagnath Yadav; Jeganmohan, Masilamani

2015-01-12

25

Structural studies on bioactive compounds. Part 29: palladium catalysed arylations and alkynylations of sterically hindered immunomodulatory 2-amino-5-halo-4,6-(disubstituted)pyrimidines.  

Science.gov (United States)

The immunological agent bropirimine 5 is a tetra-substituted pyrimidine with anticancer and interferon-inducing properties. Synthetic routes to novel 5-aryl analogues of bropirimine have been developed and their potential molecular recognition properties analysed by molecular modelling methods. Sterically challenged 2-amino-5-halo-6-phenylpyrimidin-4-ones (halo = Br or I) are poor substrates for palladium catalysed Suzuki cross-coupling reactions with benzeneboronic acid because the basic conditions of the reaction converts the amphoteric pyrimidinones to their unreactive enolic forms. Palladium-mediated reductive dehalogenation of the pyrimidinone substrates effectively competes with cross-coupling. 2-Amino-5-halo-4-methoxy-6-phenylpyrimidines can be converted to a range of 5-aryl derivatives with the 5-iodopyrimidines being the most efficient substrates. Hydrolysis of the 2-amino-5-aryl-4-methoxy-6-phenylpyrimidines affords the required pyrimidin-4-ones in high yields. Semi-empirical quantum mechanical calculations show how the nature of the 5-substituent influences the equilibrium between the 1H- and 3H-tautomeric forms, and the rotational freedom about the bond connecting the 6-phenyl group and the pyrimidine ring. Both of these factors may influence the biological properties of these compounds. PMID:10819163

Hannah, D R; Sherer, E C; Davies, R V; Titman, R B; Laughton, C A; Stevens, M F

2000-04-01

26

Synthesis and Preliminary In-Vitro Cytotoxic Activity of Various Novel 4-(N-Substituted Benzothiazolyl) Amino-7-Methoxy-6-(3-Morpholinopropoxy) Quinazoline Derivatives.  

Science.gov (United States)

A variety of 4-(N-substituted benzothiazolyl) amino-7-methoxy-6-(3-morpholinopropoxy) quinazoline were synthesized by using various N-substituted 2-amino benzothiazole, and substituted quinazoline. The structures of these compounds were confirmed by IR, Mass and 1HNMR spectral analysis. Newly synthesized compounds were tested for their In-Vitro Cytotoxic Activity using MTT assay. Results of the study indicated novel series of N-substituted (1, 3-benzothiazole)-7-methoxy-6-(3-morpholinopropoxy) quinazoline-4-yl-amine derivatives are potential class of anticancer agents. PMID:22974289

Dave, Nisharth; Gopkumar, P; Arvind, Badiger M; Sridevi, G

2012-09-10

27

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...

2010-07-01

28

SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL SCREENING OF VARIOUS N-SUBSTITUTED DERIVATIVES OF SULFONAMIDES  

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Full Text Available In the present study, a series of N-substituted sulfonamides have been synthesized. The reaction ofbenzene sulfonyl chloride (1 with O-anisidine (2 yielded N-(2-methoxyphenyl benzenesulfonamide (3, which onbromination with bromine in the presence of acetic acid gave N-(4,5-dibromo-2-methoxyphenylbenzenesulfonamide(6. The two products (3 and (6 further on treatment with alkyl halides/acyl halide in the presence of sodium hydrideyielded thirteen different N-substituted sulfonamides. The compounds were characterized by IR, EIMS and 1H-NMRand screened against acetyl cholinesterase, butyryl cholinesterase and lipoxygenase enzymes. The results revealedthat N-butyl-N-(4, 5-dibromo-2-methoxyphenylbenzene sulfonamide (6d and N-pentyl-N-(4,5-dibromo-2-methoxyphenylbenzenesulfonamide (6e exhibited good inhibitory potential against lipoxygenase.

AZIZ-UR-REHMAN, WAJEEHA TANVEER, MUHAMMAD ATHAR ABBASI, SUMBAL AFROZ, KHALID MOHAMMED KHAN, MUHAMMAD ASHRAF, AND IFTIKHAR AFZAL

2011-12-01

29

SYNTHESIS OF BIOLOGICALLY ACTIVE 2-CHLORO-N-ALKYL/ARYL ACETAMIDE DERIVATIVES  

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Full Text Available Medicinal chemistry plays an important role in development of drug for cure; maintain and improved health of human being. It is also equally important to design chemical entities for prevent the growth of micro-organism, which come in contact with human being in day-to-day life. We have synthesized 2-chloro-N-alkyl/aryl Acetamide derivatives with an aim as new bioactive agent, which can be used as anti microbial agents such as herbicides, antifungal, disinfectant. The present study involves the synthesis, purification and characterization of various N-substituted chloroacetamide derivatives. The chloroacetyl chloride treated with various aliphatic and aromatic amines at room temperature with stirring for few hours with monitoring reaction by thin layer chromatography gave 2-chloro-N-alkyl/aryl Acetamide as solid compounds. We checked the melting point of synthesized compounds with an open ended capillary tube method. The spectral techniques like Infra red and GC-MS have been used for characterization and establishment of structure of synthesized compounds. The antimicrobial screening of the synthesized chloroacetamides have shown excellent antibacterial and antifungalactivity.

S.A.Katke

2011-07-01

30

Ultrasound-assisted synthesis of 2,5-dimethyl-N-substituted pyrroles catalyzed by uranyl nitrate hexahydrate.  

Science.gov (United States)

An efficient synthesis of different novel 2,5-dimethyl-N-substituted pyrrole derivatives by the Paal-Knorr condensation has been accomplished using uranyl nitrate hexahydrate as catalyst under soft conditions and ultrasonic irradiation. The synthesized compounds were confirmed through spectral characterization using IR, (1)H NMR, (13)C NMR and mass spectra. PMID:21419686

Satyanarayana, V S V; Sivakumar, A

2011-09-01

31

Pd-catalyzed ?-arylation of trimethylsilyl enolates of ?,?-difluoroacetamides.  

Science.gov (United States)

We report the arylation and heteroarylation of ?,?-difluoro-?-(trimethylsilyl)acetamides with aryl and heteroaryl bromides catalyzed by an air- and moisture-stable palladacyclic complex containing P(t-Bu)2Cy as ligand. A broad range of electronically varied aryl and heteroaryl bromides underwent this transformation to afford ?-aryl-?,?-difluoroacetamides in high yields. Due to the electrophilicity of the fluorinated amide, this palladium-catalyzed cross-coupling reaction provides a versatile platform to generate a range of ?,?-difluoro carbonyl compounds, such as ?-aryl-?,?-difluoroketones, -acetaldehydes, -acetates, and acetic acids, and difluoroalkyl derivatives, such as 2-aryl-2,2-difluoroethanols and -ethylamines, under mild conditions. PMID:25254966

Ge, Shaozhong; Arlow, Sophie I; Mormino, Michael G; Hartwig, John F

2014-10-15

32

Fluorination of aromatic compounds by cleavage of aryl-tin bonds with F-18 F/sub 2/ and CH/sub 3/COOF  

International Nuclear Information System (INIS)

Direct fluorination of aromatic nuclei is difficult since the reaction is usually accompanied by unselective, partial, or total replacement of hydrogen. By attaching the tri-n-butyltin moiety to one position of the ring one can achieve an enhanced reactivity and site selectivity toward electrophilic fluorination. The intent of this study was to demonstrate the utility of the fluorodestannylation reaction for fluorine labelling of aromatic compounds and to compare F/sub 2/ and acetyl hypofluorite as the fluorinating agents. Thus, eight stannylated aromatic compounds (1-8) were synthesized via lithium halogen exchange of the bromo precursor and subsequent transmetallation using tri-n-butyltin chloride. The stannylated substrates were treated with F-18 F/sub 2/ and -780C and CH/sub 3/COOF at room temperature. Both reagents gave good yields of labelled aryl fluorides. Overall, acetyl hypofluorite gave more consistent yields (?70%), while F/sub 2/ gave more variable yields (54-95%). This method is currently being extended to label more complex systems such as L-Dopa with F-18 for brain studies with positron emission tomography. The authors have successfully stannylated Dopa on the ring and fluorination studies of this substrate are underway

33

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

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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

34

Activity of Antifungal Organobismuth(III Compounds Derived from Alkyl Aryl Ketones against S. cerevisiae: Comparison with a Heterocyclic Bismuth Scaffold Consisting of a Diphenyl Sulfone  

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Full Text Available A series of hypervalent organobismuth(III compounds derived from alkyl aryl ketones [XBi(5-R'C6H3-2-COR(Ar] was synthesized to investigate the effect of the compounds structural features on their antifungal activity against the yeast Saccharomyces cerevisiae. In contrast to bismuth heterocycles [XBi(5-RC6H3-2-SO2C6H4-1'-] derived from diphenyl sulfones, a systematic quantitative structure-activity relationship study was possible. The activity depended on the Ar group and increased for heavier X atoms, whereas lengthening the alkyl chain (R or introducing a substituent (R' reduced the activity. IBi(C6H4-2-COCH3(4-FC6H4 was the most active. Its activity was superior to that of the related acyclic analogues ClBi[C6H4-2-CH2N(CH32](Ar and ClBi(C6H4-2-SO2 tert-Bu(Ar and also comparable to that of heterocyclic ClBi(C6H4-2-SO2C6H4-1'-, which was the most active compound in our previous studies. Density function theory calculations suggested that hypervalent bismuthanes undergo nucleophilic addition with a biomolecule at the bismuth atom to give an intermediate ate complex. For higher antifungal activity, adjusting the lipophilicity-hydrophilicity balance, modeling the three-dimensional molecular structure around the bismuth atom, and stabilizing the ate complex appear to be more important than tuning the Lewis acidity at the bismuth atom.

Toshihiro Murafuji

2014-07-01

35

Hybrid analogues of SFTI-1 modified in P1 position by ?- and ?-amino acids and N-substituted ?-alanines.  

Science.gov (United States)

A series of compounds containing either non-proteinogenic ?-/?-amino acids or N-substituted ?-alanine residues (?-peptoid units) in P1 specificity position were synthesized based on the structure of sunflower trypsin inhibitor 1 (SFTI-1). The compounds were synthesized on a solid support; the N-substituted ?-alanines (?Nhlys and ?Nhphe) were introduced into a peptidomimetic chain via a two-step approach using acryloyl chloride and an appropriate primary amine. The inhibitory activities were characterized in vitro against bovine ?-chymotrypsin or bovine ?-trypsin. Three analogues displayed activity comparable to fully proteinogenic counterparts-monocyclic SFTI-1 and [Phe(5) ]SFTI-1. Moreover, all active peptidomimetics were resistant toward proteolytic degradation, even after 24-h incubation at room temperature. 2012 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 100: 154-159, 2013. PMID:23616099

Debowski, D; Lukajtis, R; Filipowicz, M; Strzelecka, P; Wysocka, M; L?gowska, A; Lesner, A; Rolka, K

2013-04-01

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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

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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

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

Directory of Open Access Journals (Sweden)

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

39

Evidence of N substitution by Mn in GaN  

CERN Document Server

We report on the lattice location of Mn in wurtzite GaN using beta? emission channeling. In addition to the majority substituting for Ga, we locate up to 20% of the Mn atoms in N sites. We propose that the incorporation of Mn in N sites is enabled under sufficiently high concentrations of N vacancies, and stabilized by a highly charged state of the Mn cations. Since N substitution by Mn impurities in wurtzite GaN has never been observed experimentally or even considered theoretically before, it challenges the current paradigm of transition metal incorporation in wide-gap dilute magnetic semiconductors.

Pereira, LMC; Decoster, S; Correia, JG; da Silva, MR; Vantomme, A; Arajo, JP

2012-01-01

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Amino acid sequence of the ligand-binding domain of the aryl hydrocarbon receptor 1 predicts sensitivity of wild birds to effects of dioxin-like compounds.  

Science.gov (United States)

The sensitivity of avian species to the toxic effects of dioxin-like compounds (DLCs) varies up to 1000-fold among species, and this variability has been associated with interspecies differences in aryl hydrocarbon receptor 1 ligand-binding domain (AHR1 LBD) sequence. We previously showed that LD(50) values, based on in ovo exposures to DLCs, were significantly correlated with in vitro EC(50) values obtained with a luciferase reporter gene (LRG) assay that measures AHR1-mediated induction of cytochrome P4501A in COS-7 cells transfected with avian AHR1 constructs. Those findings suggest that the AHR1 LBD sequence and the LRG assay can be used to predict avian species sensitivity to DLCs. In the present study, the AHR1 LBD sequences of 86 avian species were studied, and differences at amino acid sites 256, 257, 297, 324, 337, and 380 were identified. Site-directed mutagenesis, the LRG assay, and homology modeling highlighted the importance of each amino acid site in AHR1 sensitivity to 2,3,7,8-tetrachlorodibenzo-p-dioxin and other DLCs. The results of the study revealed that (1) only amino acids at sites 324 and 380 affect the sensitivity of AHR1 expression constructs of the 86 avian species to DLCs and (2) in vitro luciferase activity of AHR1 constructs containing only the LBD of the species of interest is significantly correlated (r (2) = 0.93, p < 0.0001) with in ovo toxicity data for those species. These results indicate promise for the use of AHR1 LBD amino acid sequences independently, or combined with the LRG assay, to predict avian species sensitivity to DLCs. PMID:22923492

Farmahin, Reza; Manning, Gillian E; Crump, Doug; Wu, Dongmei; Mundy, Lukas J; Jones, Stephanie P; Hahn, Mark E; Karchner, Sibel I; Giesy, John P; Bursian, Steven J; Zwiernik, Matthew J; Fredricks, Timothy B; Kennedy, Sean W

2013-01-01

41

Synthesis and insecticidal activities of novel N-sulfenyl-N'-tert-butyl-N,N'-diacylhydrazines. 2. N-substituted phenoxysulfenate derivatives.  

Science.gov (United States)

A series of novel N-substituted phenoxysulfenyl- N'- tert-butyl- N, N'-diacylhydrazines were designed and synthesized as insect growth regulators via the key intermediates N-chlorosulfenyl- N'- tert-butyl- N, N'-diacylhydrazines. Compared to the parent compounds, these N-substituted phenoxysulfenyl derivatives displayed better solubility and improved hydrophobicities. The insecticidal activities of the new compounds were evaluated. The results of bioassays showed that the title compounds possessed a combination of strong stomach as well as contact poison property higher than the corresponding parent compounds. In particular, N-(4-chlorophenoxy)sulfenyl -N'- tert-butyl- N-4-ethylbenzoyl- N'-3,5-dimethylbenzoylhydrazide ( IIIi) as a field testing candidate has higher stomach toxicities against oriental armyworm and tobacco cutworm than the corresponding parent compound RH-5992. Furthermore, the compound IIIi exhibits higher contact activities against Asian corn borer, tobacco cutworm, and cotton bollworm than RH-5992. PMID:18540619

Zhao, Qiqi; Shang, Jian; Huang, Zhiqiang; Wang, Kaiyun; Bi, Fuchun; Huang, Runqiu; Wang, Qingmin

2008-07-01

42

Modern Arylation Methods  

CERN Document Server

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

Convenient preparation of O-linked polymer-bound N-substituted hydroxylamines, intermediates for synthesis of N-substituted hydroxamic acids.  

Science.gov (United States)

[reaction: see text] An efficient procedure for preparation of O-linked polymer-bound N-substituted hydroxylamines by reduction of resin-bound oximes with borane.pyridine complex in the presence of dichloroacetic acid is reported. Other reducing systems commonly used for imine or oxime reduction were ineffective, including borane.pyridine in the presence of acetic acid. Oximes derived from a variety of aromatic and aliphatic aldehydes and ketones were successfully reduced. The N-substituted products were acylated and cleaved from resin to afford N-substituted hydroxamic acids. PMID:10964363

Robinson, D E; Holladay, M W

2000-09-01

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Toxicity of N-substituted aromatics to acetoclastic methanogenic activity in granular sludge.  

OpenAIRE

N-substituted aromatics are important priority pollutants entering the environment primarily through anthropogenic activities associated with the industrial production of dyes, explosives, pesticides, and pharmaceuticals. Anaerobic treatment of wastewaters discharged by these industries could potentially be problematical as a result of the high toxicity of N-substituted aromatics. The objective of this study was to examine the structure-toxicity relationships of N-substituted aromatic compoun...

Donlon, B. A.; Razo-flores, E.; Field, J. A.; Lettinga, G.

1995-01-01

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Synthesis, Antiviral and Cytotoxicity Studies of Novel N-substituted Indophenazine Derivatives  

Science.gov (United States)

A series of novel N-substituted indophenazine derivatives were synthesised and screened for antiviral activity against a panel of human pathogenic viruses. New compounds were synthesised through modifying the N-hydrogen of indophenazine moiety with different substitution and formaldehyde by Mannich reaction. The structure of the synthetic compounds was characterised by means of infra red and nuclear magnetic resonance spectral data. The compound 10H-indolo-2-Amino pyridine [3,2-b] quinoxalines inhibits Herpes simplex virus-1 and vaccinia virus at a concentration of 12 ?g/ml, and the cytotoxicy was found to be 100 ?g/ml. 4-Aminobenzene sulfonamide-10H-indolo [3,2-b] quinoxalines inhibit vaccinia virus at a concentration of 12 ?g/ml and cytotoxicy was found to be 100 ?g/ml. The anti-HIV activities of the new compounds were also screened for in vitro antiviral activity against replication of HIV-1 (IIIB) and HIV-2 (ROD) in MT-4 cells using zidovudine (AZT) as standard. Pthalimide derivative inhibited the replication of HIV-2 (EC50=11.60 ?g/ml and CC50=61.63 ?g/ml) in MT-4 cells. PMID:23440065

Selvam, P.; Lakra, D. R.; Pannecouque, C.; De Clercq, E.

2012-01-01

46

Effects of N-substitution on the activation mechanisms of 4-hydroxycyclophosphamide analogues.  

Science.gov (United States)

The activation mechanisms of the N-substituted 4-hydroxycyclophosphamide analogues 4-hydroxyifosfamide (2b), 4-hydroxytrofosfamide (2c), and 3-methyl-4-hydroxycyclophosphamide (2d) were compared with that of the unsubstituted parent compound 2a. The reaction kinetics of cis-2b, -2c, and -2d are qualitatively similar to those of 2a in that they undergo ring opening to the respective aldophosphamide intermediates 3, which can reclose to the cis- or trans-4-hydroxy isomers or undergo base-catalyzed beta-elimination to generate the corresponding phosphoramide mustard products 4. In contrast to the general acid catalysis observed for ring opening of 2a and 2d, the N-(chloroethyl)-substituted analogues 2b and 2c undergo specific base-catalyzed ring opening. This mechanistic difference was also illustrated by the rapid reaction of 2a and 2d with sodium 2-mercaptoethanesulfonate (Mesna) under acidic conditions to give the 4-(alkylthio)-substituted cyclophosphamide derivatives 5a and 5d. Compounds 2b and 2c did not react with Mesna to generate 5b and 5c under these conditions. Both the fraction of aldehyde/hydrate present at equilibrium and the cytotoxicity against L1210 cells in vitro decreased in the order 2c greater than 2b greater than 2a greater than 2d. The plasma-catalyzed acceleration of phosphoramide mustard generation previously reported for 2a was also observed for these analogues. PMID:2738883

Kwon, C H; Borch, R F

1989-07-01

47

Catalytic direct ?-arylation of simple ketones with aryl iodides.  

Science.gov (United States)

Herein we report a direct ?-arylation of simple ketones with widely available aryl iodides, combining palladium-catalyzed ketone oxidation, aryl-halide activation, and conjugate addition through a single catalytic cycle. Simple cyclic ketones with different ring-sizes, as well as acyclic ketones, can be directly arylated at the ?-position with complete site-selectivity and excellent functional group tolerance. PMID:24237137

Huang, Zhongxing; Dong, Guangbin

2013-11-27

48

?-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

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

Directory of Open Access Journals (Sweden)

Full Text Available Qosay A Al-Balas,1 Munia F Sowaileh,1 Mohammad A Hassan,1 Amjad M Qandil,1,2 Karem H Alzoubi,3 Nizar M Mhaidat,3 Ammar M Almaaytah,4 Omar F Khabour51Department of Medicinal Chemistry and Pharmacognosy, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan; 2Pharmaceutical Sciences Department, College of Pharmacy, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia; 3Department of Clinical Pharmacy, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan; 4Department of Pharmaceutical Technology, Faculty of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan; 5Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, JordanBackground: 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.Keywords: diabetes mellitus, dipeptidyl peptidase-IV, aminobenzamide derivatives, hypoglycemic activity, CDOCKER software

Al-Balas QA

2014-01-01

50

Structural Requirements of N-Substituted Spiropiperidine Analogues as Agonists of Nociceptin/Orphanin FQ Receptor  

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Full Text Available The nociceptin/orphanin FQ (NOP receptor is involved in a wide range of biological functions, including pain, anxiety, depression and drug abuse. Especially, its agonists have great potential to be developed into anxiolytics. In this work, both the ligand- and receptor-based three-dimensional quantitative structureactivity relationship (3D-QSAR studies were carried out using comparative molecular field analysis (CoMFA and comparative molecular similarity indices analysis (CoMSIA techniques on 103 N-substituted spiropiperidine analogues as NOP agonists. The resultant optimal ligand-based CoMSIA model exhibited Q2 of 0.501, R2ncv of 0.912 and its predictive ability was validated by using an independent test set of 26 compounds which gave R2pred value of 0.818. In addition, docking analysis and molecular dynamics simulation (MD were also applied to elucidate the probable binding modes of these agonists. Interpretation of the 3D contour maps, in the context of the topology of the active site of NOP, provided insight into the NOP-agonist interactions. The information obtained from this work can be used to accurately predict the binding affinity of related agonists and also facilitate the future rational design of novel agonists with improved activity.

Ling Yang

2011-12-01

51

Solvent free preparation of N-substituted maleanilic acid  

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Full Text Available Six N-maleanilic acids namely N-(4-carboxymaleanilic acid (CAMAA, N-(4-bromomaleanilic acid (BMAA, N-(4-hydroxymaleanilic acid (HMAA, N-(3-hydroxymaleanilic acid (mHMAA, N-(4-chloromaleanilic acid (CMAA and N-(4-methylmaleanilic acid (MMAA were prepared by solvent free reaction between maleic anhydride and a 4-carboxy, 4-bromo, 4-hydroxy, 3-hydroxy, 4-chloro and 4-methyl aniline derivatives in good to excellent yield. FT-IR, 1H-NMR and 13C-NMR spectra revealed the confirmation of these compounds in good agreement.DOI: http://dx.doi.org/10.4314/bcse.v27i1.15

H. Saedi

2013-04-01

52

Determination of the lipophilicity of active anticonvulsant N-substituted amides of alpha-arylalkylamine-gamma-hydroxybutyric acid.  

Science.gov (United States)

The lipophilicities of fourteen anticonvulsant active N-substituted amides of alpha-arylalkylamine-gamma-hydroxybutyric acid [I-XIV] have been determined by reversed-phase thin-layer chromatography with a mixture of methanol, TRIS buffer, and acetic acid as the solvent system. The RM value of each compound decreased linearly with increasing concentration of methanol. The partition coefficients (log P) of the amides were calculated by use of the Prolog P module of the Pallas system. Comparison of RM and log P enabled clog P values to be calculated. It was found that the anticonvulsant activity of amides [I-XIV] can be explained on the basis of their lipophilicity. PMID:10073133

Malawska, B; Tabor, A

1998-01-01

53

Synthesis, physicochemical and anticonvulsant properties of some n-substituted amides of 3-spirocycloalkylpyrrolidine-2,5-dione.  

Science.gov (United States)

The synthesis and physicochemical properties of new derivatives of N-benzyl and N-phenyl amides of 2-(3-spirocyclohexanepyrrolidine-2,5-dione) acetic acid. 4-(3-spirocyclohexanepyrrolidine-2,5-dione) benzoic acid and 4-(3-spirocyclopentanepyrrolidine-2,5-dione) benzoic acid are described. N-substituted amides were prepared by condensing the obtained acids with the corresponding phenyl- or benzylamine derivatives in DMF, in the presence of the N,N-carbonyldiimidazol (CDIM) reagent at room temperature. The compounds were evaluated for anticonvulsant activity. The portion coefficients were calculated using the Prolog P module of the Pallas system. The structure of the new amides was confirmed by elemental and spectral analyses. PMID:15005422

Obniska, Jolanta; Zejc, Alfred

2003-01-01

54

Rhodium-Catalyzed Highly Regioselective C-H Arylation of Imidazo[1,2-a]pyridines with Aryl Halides and Triflates  

International Nuclear Information System (INIS)

A convenient Rh-catalyzed C-H arylation of imidazo[1,2-a]pyridines with a variety of aryl halides or triflates has been reported. This process afforded a range of biaryl compounds in excellent yields and showed high activity and broad scope

55

Synthesis, characterization, and non-volatile memory device application of an N-substituted heteroacene.  

Science.gov (United States)

N-substituted heteroacenes have been widely used as electroactive layers in organic electronic devices, and only a few of them have been investigated in organic resistive memory devices. Here, a novel N-substituted heteroacene 2-(4'-(diphenylamino)phenyl)-4,11-bis((triisopropylsilyl)ethynyl)-1H-imidazo[4,5-b]phenazine (DBIP) has been designed, synthesized, and characterized. Sandwich-structure memory devices based on DBIP have been fabricated and the devices show non-volatile and stable memory character with good endurance performance. PMID:24382807

Wang, Chengyuan; Wang, Jiangxin; Li, Pei-Zhou; Gao, Junkuo; Tan, Si Yu; Xiong, Wei-Wei; Hu, Benlin; Lee, Pooi See; Zhao, Yanli; Zhang, Qichun

2014-03-01

56

Study of germathiazolidines and germylated dithiocetals derived from N-substituted cysteamine and methylcysteamine: synthesis and radioprotective activity  

International Nuclear Information System (INIS)

Synthesis and pharmacological studies (toxicity, radioprotective activity) of new N-substituted germathiazolidines and germylated dithioacetals prepared from N-substituted cysteamine and methylcysteamine by an acetyl group or a partial amino acid are described. A notable decrease in the toxicity and a rather important increase in the radioprotective activity of these new organometallic molecules compared to N-substituted cysteamine and methylcysteamine have been observed

57

Synthesis and Crystal Structures of N-Substituted Pyrazolines  

Directory of Open Access Journals (Sweden)

Full Text Available 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. The structures were characterized by X-ray single crystal structure determination. The dihedral angles formed between the pyrazole and the fluoro-substituted rings are 4.64(7 in 1, 5.3(4 in 2 and 4.89(6 in 3. In 4, the corresponding angles for molecules A and molecules B are 10.53(10 and 9.78(10, respectively.

Balladka Kunhanna Sarojini

2013-02-01

58

A highly efficient Pd-catalyzed decarboxylative ortho-arylation of amides with aryl acylperoxides.  

Science.gov (United States)

An efficient Pd-catalyzed decarboxylative ortho-arylation of amides with aryl acylperoxides was developed. A variety of anilides reacted with aryl acylperoxides to afford the corresponding ortho-arylation products, and N-methoxyarylamides generated phenanthridinones. PMID:25322684

Li, Dengke; Xu, Ning; Zhang, Yicheng; Wang, Lei

2014-12-01

59

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

60

Mass-spectrometric behavior of N-substituted 2-methyl-3-acetyl pyrroles  

Energy Technology Data Exchange (ETDEWEB)

In the dissociation of N-substituted derivatives of 2-methyl-3-acetylpyrroles by the action of electron impact, the methyl group splits off from the acetyl substituent, and then the exocyclic N-C bond is ruptured due to the preferential localization of the charge on the C/sub(2)/-C/sub(3)/ bond in the pyrrole ring.

Runova, E.A.; Tanchuk, N.M.; Terent' ev, P.B.; Bratkov, A.A.; Vartanyan, M.M.; Karakhanov, E.A.

1987-12-01

61

Mass-spectrometric behavior of N-substituted 2-methyl-3-acetyl pyrroles  

International Nuclear Information System (INIS)

In the dissociation of N-substituted derivatives of 2-methyl-3-acetylpyrroles by the action of electron impact, the methyl group splits off from the acetyl substituent, and then the exocyclic N-C bond is ruptured due to the preferential localization of the charge on the C/sub(2)/-C/sub(3)/ bond in the pyrrole ring

62

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 reduc 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

63

Anti-Inflammatory Activity of a Novel Family of Aryl Ureas Compounds in an Endotoxin-Induced Airway Epithelial Cell Injury Model  

Science.gov (United States)

Background Despite our increased understanding of the mechanisms involved in acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS), there is no specific pharmacological treatment of proven benefit. We used a novel screening methodology to examine potential anti-inflammatory effects of a small structure-focused library of synthetic carbamate and urea derivatives in a well established cell model of lipopolysaccharide (LPS)-induced ALI/ARDS. Methodology/Principal Findings After a pilot study to develop an in vitro LPS-induced airway epithelial cell injury model, a library of synthetic carbamate and urea derivates was screened against representative panels of human solid tumor cell lines and bacterial and fungal strains. Molecules that were non-cytotoxic and were inactive in terms of antiproliferative and antimicrobial activities were selected to study the effects on LPS-induced inflammatory response in an in vitro cell culture model using A549 human alveolar and BEAS-2B human bronchial cells. These cells were exposed for 18 h to LPS obtained from Escherichia coli, either alone or in combination with the test compounds. The LPS antagonists rhein and emodin were used as reference compounds. The most active compound (CKT0103) was selected as the lead compound and the impact of CKT0103 on pro-inflammatory IL-6 and IL-8 cytokine levels, expression of toll-like receptor-4 (TLR4) and nuclear factor kappa B inhibitor alpha (I?B?) was measured. CKT0103 significantly inhibited the synthesis and release of IL-6 and IL-8 induced by LPS. This suppression was associated with inhibition of TLR4 up-regulation and I?B? down-regulation. Immunocytochemical staining for TLR4 and I?B? supported these findings. Conclusions/Significance Using a novel screening methodology, we identified a compound CKT0103 with potent anti-inflammatory effects. These findings suggest that CKT0103 is a potential target for the treatment of the acute phase of sepsis and sepsis-induced ALI/ARDS. PMID:23144889

Cabrera-Benitez, Nuria E.; Prez-Roth, Eduardo; Casula, Milena; Ramos-Nuez, ngela; Ros-Luci, Carla; Rodrguez-Gallego, Carlos; Sologuren, Ithaisa; Jakubkiene, Virginija; Slutsky, Arthur S.; Padrn, Jos M.; Villar, Jess

2012-01-01

64

Aryl Bromides and Aryl Chlorides for the Direct Arylation of Benzylic Amines Mediated by Ruthenium(II)  

OpenAIRE

The ruthenium(II)-catalyzed sp3 CH bond arylation of benzylic amines with aryl halides is reported. In the present method, aryl iodides and, more importantly, also the cheaper aryl bromides and aryl chlorides can be applied as aryl sources. Additionally, the method does not require elaborate manipulations in a glove box and can be carried out in simple screw cap vials. Potassium pivalate proved to be beneficial for the transformation with aryl bromides or iodides as aryl source, but was no...

Dastbaravardeh, Navid; Schnu?rch, Michael; Mihovilovic, Marko D.

2013-01-01

65

Synthesis and characterization of novel N-substituted poly aniline by Triton X-100  

International Nuclear Information System (INIS)

A new N-substituted poly aniline is synthesized by insertion of polyether chain in the form of Triton X-100 onto the poly aniline backbone. In the preparation method, firstly the emeraldine base poly aniline was reacted with Na H to produce the N-anionic doped poly aniline and then contacted with chlorinated Triton X-100. The prepared N-substituted poly aniline was characterized by UV-vis, FTIR, 1H NMR spectroscopy techniques and elemental analysis. The physical properties of synthesized polymer such as electrical conductivity, thermal and electro activity properties were also studied. The prepared polymer has good solubility in common organic solvents such as T HF and chloroform

66

Tropine derivatives with central activities. Part II: Solvolysis of N-substituted nortropine methanesulfonates.  

Science.gov (United States)

The preparation and the reaction kinetical properties in solvolysis of a series of N-substituted nortropine methanesulfonates 1-8 are described. It was found that the rate of solvolysis depends on the nature of the N-substituents considerably. The solvolysis rates can be brought into correlation with the electron donating and withdrawing and steric properties of the N-substituents. Methane-sulfonates of other two bicyclic aminoalcohols 10, 11 were also prepared and kinetically studied. PMID:191036

Scheiber, P; Kreiss, G; Ndor, K

1976-01-01

67

ON THE ANTIOXIDANT EFFECTIVENESS OF N,NSUBSTITUTED P-PHENYLENEDIAMINES  

OpenAIRE

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 thes...

Vladimr Luke; Erik Klein; Zuzana Cibulkov

2004-01-01

68

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

OpenAIRE

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

69

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

70

Iron catalyzed oxidative assembly of N-heteroaryl and aryl metal reagents using oxygen as an oxidant.  

Science.gov (United States)

An equivalent amount of N-heteroaryl and aryl Grignard or lithium reagents, after mediation by an equivalent of titanate, was facilely coupled to furnish N-heteroaryl-aryl compounds under the catalysis of FeCl3/TMEDA at ambient temperature using oxygen as an oxidant. Most of the common N-heteroaryls were all good candidates, and thus provided a general, green and pratical protocol for the flexible construction of various N-heteroaryl-aryl structures. PMID:25466876

Liu, Kun Ming; Liao, Lian Yan; Duan, Xin Fang

2015-01-21

71

Protective role of aryl and alkyl diselenides on lipid peroxidation  

International Nuclear Information System (INIS)

The concept that selenium-containing molecules may be better nucleophiles (and therefore antioxidants) than classical antioxidants has led to the design of synthetic organoselenium compounds. In the present study we appraised the antioxidant potential, thiol peroxidase activity, and rate of dithiotreitol and reduced glutathione oxidation of simple organodiselenide compounds in rats and mice. The present results demonstrate that alkyl and aryl diselenides are antioxidant compounds. We verified that the substitution on the aromatic moiety of diphenyl diselenide or the replacement of on aryl group by an alkyl substitute on diselenides changes their antioxidant and thiol peroxidase-like properties. The diaryl diselenides (PhSe)2 and (p-ClPhSe)2 presented higher thiol peroxidase activity and demonstrated better antioxidant potential than the other diselenides tested. In fact, the results revealed that alkyl diselenides, at low concentrations, were prooxidants and that aryl diselenides did not present this effect. Alkyl diselenides [(C2H5Se)2 and (C3H7Se)2] demonstrated a higher potential for -SH group oxidation than aryl diselenides. In addition, this study demonstrated that diselenide protection against lipid peroxidation was different in mice and rats. The compounds tested acted more as antioxidants in the brains of mice than in the brains of ratsrats

72

N-substituted phenoxazine and acridone derivatives: structure-activity relationships of potent P2X4 receptor antagonists.  

Science.gov (United States)

P2X4 receptor antagonists have potential as drugs for the treatment of neuropathic pain and neurodegenerative diseases. In the present study the discovery of phenoxazine derivatives as potent P2X4 antagonists is described. N-Substituted phenoxazine and related acridone and benzoxazine derivatives were synthesized and optimized with regard to their potency to inhibit ATP-induced calcium influx in 1321N1 astrocytoma cells stably transfected with the human P2X4 receptor. In addition, species selectivity (rat, mouse, human) and receptor subtype selectivity (versus P2X1,2,3,7) were investigated. The most potent P2X4 antagonist of the present series was N-(benzyloxycarbonyl)phenoxazine (26, PSB-12054) with an IC(50) of 0.189 ?M and good selectivity versus the other human P2X receptor subtypes. N-(p-Methylphenylsulfonyl)phenoxazine (21, PSB-12062) was identified as a selective P2X4 antagonist that was equally potent in all three species (IC(50): 0.928-1.76 ?M). The compounds showed an allosteric mechanism of action. The present study represents the first structure-activity relationship analysis of P2X4 antagonists. PMID:23075067

Hernandez-Olmos, Victor; Abdelrahman, Aliaa; El-Tayeb, Ali; Freudendahl, Diana; Weinhausen, Stephanie; Mller, Christa E

2012-11-26

73

Complexation, thermal and catalytic studies of N-substituted piperazine, morpholine and thiomorpholine with some metal ions  

Science.gov (United States)

Several Cu(II), Pt(II) and Ni(II) complexes of N-substituted, piperazine (NN donor), morpholine (NO donor) and thiomorpholine (NS donor) derivatives were synthesized and their thermal behavior and catalytic activity in epoxidation reaction of cis-diphenylethylene were studied using oxygen sources NaOCl. The coordination compounds of Cu(II), Pt(II) and Ni(II) having general formula [MLCl]Cl, [ML2l]Cl2 or [ML]Cl2 with tetra coordinated geometry around metal ions have been isolated as solid. All the ligands and complexes were identified by spectroscopic methods and elemental analysis, magnetic measurements, electrical conductance and thermal analysis. A square planer structures have been proposed for all complexes. The thermal stability of the complexes discussed in terms of ligands donor atoms, geometry and central metal ions. The complexes have a similar thermal behavior for the selected metal ions. The thermogravimetric analyses suggest high thermal stability for most complexes followed by thermal decomposition in different steps. The decomposition processes were observed as water elimination, chloride anion removal and degradation of the organic ligands. Catalytic ability of the complexes were examined and found that all the complexes can effectively catalyze the epoxidation of cis-stilbene with NaOCl.

Kacan, Mesut; Turkyilmaz, Murat; Karabulut, Ferhat; Altun, Ozlen; Baran, Yakup

2014-01-01

74

An Expeditious Synthesis of N-substituted Pyrroles via Microwave-Induced Iodine-Catalyzed Reactions under Solventless Conditions  

Directory of Open Access Journals (Sweden)

Full Text Available An expeditious synthesis of N-substituted pyrroles has been developed by reacting 2,5-dimethoxy tetrahydrofuran and several amines using a microwave-induced molecular iodine-catalyzed reaction under solventless conditions.

Debasish Bandyopadhyay

2010-04-01

75

Inhibition of Bfl-1 with N-Aryl Maleimides  

OpenAIRE

High throughput screening of 66,000 compounds using competitive binding of peptides comprising the BH3 domain to anti-apoptotic Bfl-1 led to the identification of fourteen validated hits as inhibitors of Bfl-1. N-Aryl maleimide 1 was among the validated hits. A chemical library encompassing over 280 analogs of 1 was prepared following a two-step synthesis. Structure-activity studies for inhibition of Bfl-1 by analogs of N-aryl maleimide 1 revealed a preference for electron-withdra...

Cashman, John R.; Macdonald, Mary; Ghirmai, Senait; Okolotowicz, Karl J.; Sergienko, Eduard; Brown, Brock; Garcia, Xochella; Zhai, Dayong; Reed, John C.

2010-01-01

76

Palladium-Catalyzed ?-Arylation of Arylketones at Low Catalyst Loadings.  

Science.gov (United States)

A general catalytic protocol for the ?-arylation of aryl ketones has been developed. It involves the use of a preformed, bench-stable Pd-N-heterocyclic carbene pre-catalyst bearing IHept as an ancillary ligand, and allows the coupling of various functionalized coupling partners at very low catalyst loading. Careful choice of the solvent/base system was crucial to obtain optimum catalyst performance. The pre-catalyst was also successfully tested in the synthesis of an industrially relevant compound. PMID:25414140

Marelli, Enrico; Corpet, Martin; Davies, Sian R; Nolan, Steven P

2014-12-22

77

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

78

Experimental and theoretical study of [N-substituted] p-aminoazobenzene derivatives as corrosion inhibitors for mild steel in sulfuric acid solution  

Science.gov (United States)

[N-substituted] p-aminoazobenzene derivatives (1), (2), (3), (4) and (5) were prepared and investigated as corrosion inhibitors for mild steel in 1 M H2SO4 solution by weight loss measurements. It has been observed that the corrosion rate decreases, inhibition efficiencies increase and surface coverage degree increases with increasing inhibitor concentration. Inhibition efficiencies for prepared compounds were ordered: (1) > (2) > (5) > (4) > (3) with the highest inhibiting efficiency of 63% for 10-3 M. The values of ?Gadso are showing physisorption effect for all prepared compounds. Semiempirical molecular orbital calculations for (1), (2), (3), (4) and (5) could be used as a useful tool to obtain information for explaining the nature of interaction between the metal surface and the organic molecule as a corrosion inhibitor.

Shihab, Mehdi Salih; Al-Doori, Hanan Hussien

2014-11-01

79

Synthesis and biological activity of a new class of sulfone-linked pyrrolylpyrazoles and pyrrolylisoxazoles from methyl-3-aryl-2-(E-arylethenesulfonyl)acrylate.  

Science.gov (United States)

A new class of sulfone-linked bis heterocycles, methyl-3-(4'-aryl-1'H-pyrazol-3'-ylsulfonyl)-4-aryl-3H-pyrrole-3-carboxylate (8), methyl-3-(1'-phenyl-3',5'-diaryl-1'H-pyrazol-4'-ylsulfonyl)-4-aryl-3H-pyrrole-3-carboxylate (9) and methyl-3-(3',5'-diarylisoxazol-4'-ylsulfonyl)-4-aryl-3H-pyrrole-3-carboxylate (10) were prepared by the regioselective reaction of methyl-3-aryl-2-(E-arylethenesulfonyl)acrylate (2) with tosylmethyl isocyanide followed by fuctionalization of olefin moiety with 1,3-dipolar reagents. The lead compounds were tested for their antimicrobial activity. PMID:19881267

Padmavathi, Venkatapuram; Radha Lakshmi, Thunga; Mahesh, Konda; Padmaja, Adivireddy

2009-11-01

80

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

81

Solid-phase exchange radioiodination of aryl iodides. Facilitation by ammonium sulfate  

International Nuclear Information System (INIS)

A mild and simple technique for the synthesis of aryl radioiodides of high specific activity involving a solid-phase exchange between no-carrier-added radioiodide and unactivated aryl iodides is described. Mildly acidic, oxidizing conditions, provided by the in situ thermal decomposition of ammonium sulfate, appear to be necessary for the success of the exchange. Typical isolated radiochemical yields of >70% have been obtained for a variety of aryl iodides, including various aralkyl amines, guanidines, carboxylic acids, and amino acids. Specific activities of up to 100 Ci/mmol of our model compound, (m-[125I]iodobenzyl)guanidine, have been achieved. Preliminary experiments suggest that, with this technique interhalogen exchange of aryl bromides with radioiodine is a feasible approach to the preparation of no-carrier-added aryl radioiodides

82

Syntheses of some N-substituted hydrazines by the anhydrous chloramine process  

OpenAIRE

ClNH2, produced in the gas phase by the reaction of Cl2 and NH3, reacts with various primary and secondary amines in nonaq. solvents in the presence of a fixed base to form the corresponding N-substituted hydrazines. The hydrazines synthesized include PhNHNH2 [100-63-0], p-tolylhydrazine [539-44-6], H2NCH2CH2NHNH2 [14478-61-6], N-aminopyrrolidine [16596-41-1], and N-aminopiperidine [2213-43-6]. Apparently, no hydrazine is formed when the reaction is carried out in the absence of fixed ...

Jain, Sr; Chellappa, D.

1985-01-01

83

Enantioselective ?-Arylation of Ketones with Aryl Triflates Catalyzed by Difluorphos Complexes of Palladium and Nickel  

OpenAIRE

The asymmetric ?-arylation of ketones with aryl triflates is described, and the use of this electrophile with nickel and palladium catalysts containing a segphos derivative increases substantially the scope of highly enantioselective arylations of ketone enolates. The combination of aryl triflates as reactant, difluorphos as ligand, palladium catalysts for reactions of electron-neutral to (or) electron-rich aryl triflates, and nickel catalysts for reactions of electron-poor aryl triflates le...

Liao, Xuebin; Weng, Zhiqiang; Hartwig, John F.

2008-01-01

84

Palladium-Catalyzed Aryl-Aryl Bond Formation Through Double C-H Activation  

Science.gov (United States)

Aryl-aryl bond formation constitutes one of the most important subjects in organic synthesis. The recently developed direct arylation reactions for the formation of aryl-aryl bond have emerged as very attractive alternatives to traditional cross-coupling reactions. Particularly, the direct arylation through double C-H activation using the simple arenes as both coupling partners is a highly economic and attractive method. In this chapter, the recent progress of Pd-catalyzed aryl-aryl oxidative coupling reactions through double C-H activation is presented.

You, Shu-Li; Xia, Ji-Bao

85

Synthesis of fluorine-18 labeled 1,1-difluoro-2,2-dichloroethyl aryl ethers by isotopic exchange  

International Nuclear Information System (INIS)

Isotopic exchange reactions involving fluorine-18 produce carrier-added radiolabeled compounds, and this method has been applied to the synthesis of alkyl and aryl fluorides, and trifluoromethyl compounds. As part of an effort to examine the reactivities of 1,1-difluoro-2,2-dichloroethyl aryl ethers, the authors report the unexpected facile 18F-for-19F isotopic exchange in these compounds

86

Synthesis of N-substituted 6-trifluoromethyl-1,3-oxazinanes  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Este trabalho apresenta a sntese de duas novas sries de 6-trifluormetil-1,3-oxazinanas N-substitudas e 6-trifluormetil-1,3-oxazinan-2-onas N-substitudas, a partir da ciclizao de 4-ilamino-1,1,1-trifluor-butan-2-is com formaldedo e trifosgnio, respectivamente. Os 4-ilamino-1,1,1-trifluor-but [...] an-2-is foram obtidos atravs da reao de reduo dos precursores 4-ilamino-1,1,1-trifluor-but-3-en-2-onas, utilizando hidrognio e 10% Pd/C, com bons rendimentos. Abstract in english This work reports the synthesis of two new series of N-substituted 6-trifluoromethyl-1,3-oxazinanes and N-substituted 6-trifluoromethyl-1,3-oxazinan-2-ones from the cyclization of 4-ylamino-1,1,1-trifluoro-butan-2-ols with formaldehyde and triphosgene, respectively. The 4-ylamino-1,1,1-trifluoro-but [...] an-2-ols were obtained in good yields from the reduction of the parent 4-ylamino-1,1,1-trifluoro-but-3-en-2-ones with hydrogen and 10% Pd/C.

Nilo, Zanatta; Adriana M. C., Squizani; Leonardo, Fantinel; Fabiane M., Nachtigall; Deise M., Borchhardt; Helio G., Bonacorso; Marcos A. P., Martins.

1255-12-01

87

Organic Transformations on ?-Aryl Organometallic  

OpenAIRE

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

88

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

89

Reaction of aryl diazonium tetrafluoro borates with allyl methacrylate in the presence of rhodanide-anion  

International Nuclear Information System (INIS)

Reaction of aryl diazonium tetrafluoro borates (I) with allyl ester of methacrylic acid in the water-acetone (1:5) medium is studied by means of IR spectroscopy and 1H NMR. It is established that (I) reacts with aryl methacrylate in the presence of rhodanide-anion and catalytic quantities of copper salts with the formation of allyl esters of 2-thiocyanato-2-methyl-3-aryl propionic acids with the yield of 32-56%. Allyl fragment of biunsaturated compound shows no reaction under the tested conditions

90

Regioselective ruthenium-catalyzed carbonylative direct arylation of five-membered and condensed heterocycles.  

Science.gov (United States)

A ruthenium-catalyzed carbonylative C?H bond arylation process for the three-component synthesis of complex aryl-(hetero)aryl ketones in an aqueous solution has been developed. By exploiting the ortho-activating effect of nitrogen-containing directing groups, a regioselective, successive twofold C(sp(2))-C(sp(2)) bond formation has been achieved. This straightforward catalytic process provides access to versatile products prevalent in multiple bioactive compounds and supplies a valuable functional group for subsequent transformations. PMID:24519915

Pospech, Jola; Tlili, Anis; Spannenberg, Anke; Neumann, Helfried; Beller, Matthias

2014-03-10

91

Microwave-assisted synthesis and biological evaluation of 3,4-diaryl maleic anhydride/N-substituted maleimide derivatives as combretastatin A-4 analogues.  

Science.gov (United States)

A series of new CA-4 analogues bearing maleic anhydride/N-substituted maleimide moiety were synthesized via a microwave-assisted process. They were evaluated for the anti-proliferative activities against three tumor cell lines (SGC-7901, HT-1080 and KB). Most compounds showed moderate potencies in micromolar range, with the most promising analogue 6f showing active at submicromolar concentration against HT-1080 cancer cells which was selected to investigate the antitumor mechanisms. In addition, molecular docking studies within the colchicine binding site of tubulin were also in good agreement with the tubulin polymerization inhibitory data and provided a basis for further structure-guided design of novel CA-4 analogues. PMID:25529737

Guan, Qi; Zuo, Daiying; Jiang, Nan; Qi, Huan; Zhai, Yanpeng; Bai, Zhaoshi; Feng, Dongjie; Yang, Lei; Jiang, Mingyang; Bao, Kai; Li, Chang; Wu, Yingliang; Zhang, Weige

2015-02-01

92

Anticancer activity and anti-inflammatory studies of 5-aryl-1,4-benzodiazepine derivatives.  

Science.gov (United States)

A series of 5-aryl-1,4-benzodiazepines with chloro- or fluoro-substituents in the second ring have been synthesized and their anti-inflammatory, myeloperoxidase and anticancer properties studied. The synthesized compounds showed potential anti-inflammatory and anticancer activities, which were enhanced in the presence of a chloro-substituent in the second ring of the 5-aryl-1,4- benzodiazepine. PMID:22263787

Sandra, Cortez-Maya; Eduardo, Cortes Cortes; Simon, Hernandez-Ortega; Teresa, Ramirez Apan; Antonio, Nieto Camacho; Lijanova, Irina V; Marcos, Martinez-Garcia

2012-07-01

93

An Improved Protocol for the Pd-catalyzed ?-Arylation of Aldehydes with Aryl Halides  

OpenAIRE

An improved protocol for the Pd-catalyzed ?-arylation of aldehydes with aryl halides has been developed. The new catalytic system allows for the coupling of an array of substrates including challenging electron-rich aryl bromides and less reactive aryl chlorides. The utility of this method has been demonstrated in a new total synthesis of ()-sporochnol.

Marti?n, Rube?n; Buchwald, Stephen L.

2008-01-01

94

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

Directory of Open Access Journals (Sweden)

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

95

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

96

Palladium-catalyzed aminosulfonylation of aryl halides.  

OpenAIRE

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

97

Aryl bromides as inexpensive starting materials in the catalytic enantioselective arylation of aryl aldehydes: the additive TMEDA enhances the enantioselectivity.  

Science.gov (United States)

We used aryl bromides as inexpensive starting materials to enantioselectively arylate aldehydes in one pot. Aryl bromides readily transfer aryls to aryllithiums with n-butyllithium, successively to triarylaluminums with aluminum chloride, and then to aryltitaniums with titanium isopropoxide. Finally aryltitaniums arylate aldehydes catalyzed by (S)-H8-BINOL-Ti(Oi-Pr)2 in excellent yields and enantioselectivities. The additive TMEDA evidently suppresses the racemic background reaction promoted by LiCl generated from salt metathesis. This procedure represents a cost-effective and operationally convenient method for enantioenriched diarylmethanols. PMID:25279967

Yang, Yong-Xin; Liu, Yue; Zhang, Lei; Jia, Yan-E; Wang, Pei; Zhuo, Fang-Fang; An, Xian-Tao; Da, Chao-Shan

2014-11-01

98

Iridium-catalyzed silylation of aryl C-h bonds.  

Science.gov (United States)

A method for the iridium-catalyzed silylation of aryl C-H bonds is described. The reaction of HSiMe(OSiMe3)2 with arenes and heteroarenes catalyzed by the combination of [Ir(cod)(OMe)]2 and 2,4,7-trimethylphenanthroline occurs with the aromatic compound as the limiting reagent and with high levels of sterically derived regioselectivity. This new catalytic system occurs with a much higher tolerance for functional groups than the previously reported rhodium-catalyzed silylation of aryl C-H bonds and occurs with a wide range of heteroarenes. The silylarene products are suitable for further transformations, such as oxidation, halogenation, and cross-coupling. Late-stage functionalization of complex pharmaceutical compounds was demonstrated. PMID:25514197

Cheng, Chen; Hartwig, John F

2015-01-21

99

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

OpenAIRE

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...

Pati, Hari N.; Das, Umashankar; Kawase, Masami; Sakagami, Hiroshi; Balzarini, Jan; Clercq, Erik; Dimmock, Jonathan R.

2008-01-01

100

Palladium-Catalyzed Thiocarbonylation of Aryl, Vinyl, and Benzyl Bromides  

DEFF Research Database (Denmark)

A catalytic protocol for synthesis of thioesters from aryl, vinyl, and benzyl bromides as well as benzyl chlorides was developed using only stoichiometric amounts of carbon monoxide, produced from a solid CO precursor inside a two-chamber system. As a catalytic system, the combination of bis(benzonitrile) palladium(II) chloride and Xantphos furnished the highest yields of the desired compounds, along with the weak base, NaOAc, in anisole at 120 C. The choice of catalytic system as well as solvent turned out to be important in order to ensure a high chemoselectivity in the reaction. Both electron-rich and electron-deficient aryl bromides worked well in this reaction. Addition of 1 equiv of sodium iodide to the reaction improved the chemoselectivity with the electron-deficient aryl bromides. The thiol scope included both aryl and alkyl thiols, including 2-mercaptobenzophenones, whereby a thiocarbonylation followed by a subsequent McMurry coupling yielded differently substituted benzothiophenes. It was demonstrated that the methodology could be applied for (13)C introduction into the thiophene ring.

Burhardt, Mia; Ahlburg, Andreas

2014-01-01

101

Selective, nickel-catalyzed hydrogenolysis of aryl ethers.  

Science.gov (United States)

Selective hydrogenolysis of the aromatic carbon-oxygen (C-O) bonds in aryl ethers is an unsolved synthetic problem important for the generation of fuels and chemical feedstocks from biomass and for the liquefaction of coal. Currently, the hydrogenolysis of aromatic C-O bonds requires heterogeneous catalysts that operate at high temperature and pressure and lead to a mixture of products from competing hydrogenolysis of aliphatic C-O bonds and hydrogenation of the arene. Here, we report hydrogenolyses of aromatic C-O bonds in alkyl aryl and diaryl ethers that form exclusively arenes and alcohols. This process is catalyzed by a soluble nickel carbene complex under just 1 bar of hydrogen at temperatures of 80 to 120C; the relative reactivity of ether substrates scale as Ar-OAr>Ar-OMe>ArCH(2)-OMe (Ar, Aryl; Me, Methyl). Hydrogenolysis of lignin model compounds highlights the potential of this approach for the conversion of refractory aryl ether biopolymers to hydrocarbons. PMID:21512027

Sergeev, Alexey G; Hartwig, John F

2011-04-22

102

Novel progesterone receptor modulators: 4-aryl-phenylsulfonamides.  

Science.gov (United States)

We have developed a new series of progesterone receptor modulators based upon the 4-aryl-phenylsulfonamide. Initial work in the series afforded potent compounds with good properties, however an advanced intermediate proved to be genotoxic in a non-GLP Ames assay following metabolic activation. We subsequently solved this problem and identified advanced leads which demonstrated oral efficacy in rhesus monkey pharmacodynamic and kinetics models. PMID:23079530

McComas, Casey; Cohen, Jeffrey; Huselton, Christine; Marella, Michael; Melenski, Edward; Mugford, Cheryl; Slayden, Ov; Winneker, Richard; Wrobel, Jay; Yudt, Matthew R; Fensome, Andrew

2012-12-01

103

Antileishmanial, Antimicrobial and Antifungal Activities of Some New Aryl Azomethines  

OpenAIRE

A series of eighteen azomethines has been synthesized by the reaction of appropriate primary aromatic amines with aryl and/or heteroaryl carboxaldehydes. The synthesized azomethines have been evaluated for their in vitro antileishmanial, antibacterial and antifungal activities. The results revealed some antifungal activity of most of the synthesized compounds, whereas the antileishmaniasis activity results highlighted that all synthesized azomethines inhibited parasite growth and most of them...

Masoom Yasinzai; Dildar Ali; Madkour, Hassan M. F.; Al-kahraman, Yasser M. S. A.

2010-01-01

104

Synthesis and antioxidant properties of novel N-substituted indole-2-carboxamide and indole-3-acetamide derivatives.  

Science.gov (United States)

A series of N-substituted indole-2-carboxamide and indole-3-acetamide derivatives have been prepared and their in vitro effects on rat liver lipid peroxidation levels and superoxide anion formation were determined. The results clearly demonstrate that indole derivatives 4, 5, 10, 15, 17 are very efficient antioxidants compared to alpha-tocopherol. PMID:12207283

Olgen, Sreyya; Coban, Tlay

2002-07-01

105

Establishing Dependences between Different Lipophilic Parameters of New Potentially Biologically Active N-Substituted-2-Phenylacetamide Derivatives by Applying Multivariate Methods.  

Science.gov (United States)

Lipophilicity, a very important parameter in the potential biological activities of molecules, was investigated for newly synthesized N-substituted-2-phenylacetamide derivatives. The determination was carried out in two ways: first experimentally, by applying thin-layer chromatography (TLC) on reversed-phase TLC (RPTLC) RP18F254s in the presence of one protic (methanol) and one aprotic solvent (acetonitrile) and then mathematically, by using different software packages. The intercept of the linear dependence between volume fractions of the organic solvent and the retention parameters obtained by TLC is known as the retention chromatographic constant, RM (0), while the slope represents the m value. In order to establish the dependences between the partition coefficient, log P as the standard measure of lipophilicity and the alternative lipophilic parameters obtained experimentally by TLC, RM (0) and m values, linear regression analysis and multivariate methods, cluster analysis (CA) and principal component analysis (PCA), were used. All applied methods gave approximately similar results. Although there is a linear dependence between the two chromatographic parameters, the retention constant, RM (0), and the m values, only RM (0) shows suitable similarity with the standard measure of lipophilicity of the investigated N-substituted-2-phenylacetamide derivatives at the given conditions. The existence of this resemblance proves that the chromatographic retention constant, RM (0), obtained by RPTLC could be successfully used for the description of lipophilicity of investigated compounds. On the other hand, the results confirmed that the applied linear regression analysis and the multivariate analysis (CA and PCA) have the ability to compare lipophilic parameters of the investigated phenylacetamide derivatives obtained in different ways. PMID:24981978

Vastag, Gyngyi; Apostolov, Suzana; Matijevi?, Borko; Petrovi?, Slobodan

2015-02-01

106

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

107

A new acylamidase from Rhodococcus erythropolis TA37 can hydrolyze N-substituted amides.  

Science.gov (United States)

A new acylamidase was isolated from Rhodococcus erythropolis TA37 and characterized. N-Substituted acrylamides (isopropyl acrylamide, N,N-dimethyl-aminopropyl acrylamide, and methylene-bis-acrylamide), acid para-nitroanilides (4'-nitroacetanilide, Gly-pNA, Ala-pNA, Leu-pNA), and N-acetyl derivatives of glycine, alanine, and leucine are good substrates for this enzyme. Aliphatic amides (acetamide, acrylamide, isobutyramide, n-butyramide, and valeramide) are also used as substrates but with less efficiency. The enzyme subunit mass by SDS-PAGE is 55 kDa. Maximal activity is exhibited at pH 7-8 and 55C. The enzyme is stable for 15 h at 22C and for 0.5 h at 45C. The Michaelis constant (K(m)) is 0.25 mM with Gly-pNA and 0.55 mM with Ala-pNA. The acylamidase activity is suppressed by inhibitors of serine proteases (phenylmethylsulfonyl fluoride and diisopropyl fluorophosphate) but is not suppressed by inhibitors of aliphatic amidases (acetaldehyde and nitrophenyl disulfides). The N-terminal amino acid sequence of the acylamidase is highly homologous to those of two putative amidases detected from sequenced R. erythropolis genomes. It is suggested that the acylamidase together with the detected homologs forms a new class within the amidase signature family. PMID:21073421

Lavrov, K V; Zalunin, I A; Kotlova, E K; Yanenko, A S

2010-08-01

108

ON THE ANTIOXIDANT EFFECTIVENESS OF N,NSUBSTITUTED P-PHENYLENEDIAMINES  

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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

109

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

110

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

111

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

112

Enantioselective ?-Arylation of Ketones with Aryl Triflates Catalyzed by Difluorphos Complexes of Palladium and Nickel  

Science.gov (United States)

The asymmetric ?-arylation of ketones with aryl triflates is described, and the use of this electrophile with nickel and palladium catalysts containing a segphos derivative increases substantially the scope of highly enantioselective arylations of ketone enolates. The combination of aryl triflates as reactant, difluorphos as ligand, palladium catalysts for reactions of electron-neutral to (or) electron-rich aryl triflates, and nickel catalysts for reactions of electron-poor aryl triflates led to a series of ?-arylations of tetralone, indanone, cyclopentanone, and cyclohexanone derivatives with electron-rich and electron poor aryl electrophiles. Enantioselectivities ranged from 7098% with ten examples over 90%. Systematic studies on these ?-arylations have revealed a number of factors that affect enantioselectivity. Ligands containing biaryl backbones with small dihedral angles generate catalysts that react with higher enantioselectivity than related ligands with larger dihedral angles. In addition, faster rates for reactions of aryl triflates vs those for reactions of aryl bromides allow the ?-arylations of aryl triflates to be conducted at lower temperatures, and this lower temperature improves enantioselectivity. Finally, studies that compare the enantioselectivities of catalytic reactions to those of stoichiometric reactions of isolated [(segphos)Pd(Ar)(Br)], [(segphos)Pd(Ar)(I)] and [(segphos)Ni(C6H4-4-CN)Br] suggest that catalyst decomposition affects enantioselectivity. PMID:18076166

Liao, Xuebin; Weng, Zhiqiang; Hartwig, John F.

2008-01-01

113

Synthesis, anticonvulsant, antioxidant and binding interaction of novel N-substituted methylquinazoline-2,4(1H, 3H)-dione derivatives to bovine serum albumin: A structure-activity relationship study  

Science.gov (United States)

A novel class of N-substituted glycosmicine derivatives was synthesized, and their anticonvulsant, antioxidant activity and interaction with bovine serum albumin (BSA) were evaluated. The synthesized compounds 4a-j were examined for anticonvulsant activity by maximal electroshock induced seizures (MESs) test and their neurotoxic effects were determined by rotorod test in mice. The structure-activity relationships (SARs) of these compounds were also investigated. Compounds 4d, 4g, 4i and 4j were found to have good protective effect from seizure. The in vitro antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging assay. The interaction between novel N-substituted methylquinazoline-2,4(1H, 3H)-dione (NMQ) and BSA was analyzed by fluorescence and ultraviolet spectroscopy at 304 K under simulative physiological conditions. BSA fluorescence quenched by NMQ is discussed according to the Stern-Volmer equation. The binding constant and binding sites of NMQ with BSA were calculated. According to Forster non-radiation energy transfer theory, the binding distance (r) between NMQ and BSA was calculated.

Prashanth, M. K.; Madaiah, M.; Revanasiddappa, H. D.; Veeresh, B.

2013-06-01

114

A survey of the cleavage of aryl-metal bonds by elemental fluorine  

International Nuclear Information System (INIS)

The reaction of elemental fluorine with phenyl derivatives of tin, lead, germanium, silicon, mercury, and thallium has been studied with the aim of developing a general method for labelling aromatic compounds with radioactive 18F. Rapid synthesis of fluorobenzene was achieved in varying chemical yields up to 70 percent, depending largely upon the metal substrate used, with aryl-tin compounds giving the highest yields. Radiochemical yields are also given for the synthesis of 18/F-fluoro-benzene from the cleavage of aryl-tin bonds with 18F-F2

115

Dramatic mechanistic change in acid-catalyzed arylation of azafulleroids depending on their ambident N/C basicity: formation of cyclopentene centered pentakisadduct.  

Science.gov (United States)

Azafulleroid, amino-bridged [5,6]-open fullerene, has the ambident N/C basicity of the incorporated enamine moiety. Acid-catalyzed arylation of N-substituted azafulleroids proceeded via two types of initial N/C protonation to perform monoarylation or 1,4-bisarylation for the N-alkyl substituents and shuttlecock-type pentakisarylation for the N-phenyl substituent. The dramatic product change was explained by considering the possible mechanism as well as the DFT computational results. PMID:25204634

Ikuma, Naohiko; Doi, Yuta; Fujioka, Koichi; Mikie, Tsubasa; Kokubo, Ken; Oshima, Takumi

2014-11-01

116

Nickel or Phenanthroline Mediated Intramolecular Arylation of sp3 CH Bonds Using Aryl Halides  

Science.gov (United States)

The development of an intramolecular arylation of sp3 CH bonds adjacent to nitrogen using aryl halides is described. Arylation was accomplished using either Ni(COD)2 or 1,10-phenanthroline in sub-stoichiometric amounts and the reaction conditions were applied to a variety of electronically differentiated benzamide substrates. Preliminary studies suggest a mechanism involving aryl and alkyl radical intermediates. PMID:24256509

Wertjes, William C.; Wolfe, Lydia C.; Waller, Peter J.; Kalyani, Dipannita

2013-01-01

117

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

Directory of Open Access Journals (Sweden)

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

118

Inhibitory effects of N-(substituted benzoylamino)-4-ethyl-1,2,3,6-tetrahydropyridines on nitric oxide generation in stimulated raw 264.7 macrophages.  

Science.gov (United States)

There has been great interest in reactive nitrogen intermediates and nitric oxide production in macrophages, particularly because of their contributory role in several pathophysiological conditions during acute and chronic inflammation. Several N-(substituted benzoylamino)-4-ethyl-1,2,3,6-tetrahydropyridines were previously synthesized as potential antiinflammatory agents. In the present study, the effects of four previously synthesized tetrahydropyridines (THPs) on cyclooxygenase (COX)-1 and COX-2 were screened and the effects of these compounds on lipopolysaccharide (LPS)-induced (2 micrograms/ml) nitric oxide and inducible nitric oxide synthase (iNOS) activity in RAW 264.7 macrophages were examined. 4-Bromo THP showed 9.4 microM of IC50 as the most potent derivative among the tested THPs followed by 4-nbuthyl, 4-fuoro, and 4-methyl THP with IC50 values of 30.9, 38.9 and 80.3 microM, respectively (indomethacin IC50 = 53.8 microM). None of the tested compounds showed cytotoxic effects to the RAW 264.7 macrophages. All of the tested THPs exhibited COX-1 and COX-2 nonselective inhibition. These results suggest that previously synthesized THP derivatives may have dual effects through inhibiting both COX and nitric oxide by inhibiting iNOS. PMID:12224381

Yoon, K; Soliman, K; Redda, K

2002-01-01

119

Pd(ii)-catalyzed C-H arylation of aryl and benzyl Weinreb amides.  

Science.gov (United States)

The first example of palladium-catalyzed ortho-C-H arylation of aryl and benzyl Weinreb amides was developed, in which HOTf was used as a key promoter. This method exhibits good functional group tolerance, a broad substrate scope of both Weinreb amides and aryl iodides, high mono-selectivity and mild reaction conditions. PMID:25380404

Wang, Yan; Zhou, Kai; Lan, Quan; Wang, Xi-Sheng

2015-01-14

120

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

OpenAIRE

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 ant...

Rafiuzzaman SaeedulHaq; Muhammad Baseer; Farzana Latif Ansari; Zaman Ashraf

2011-01-01

121

Discovery of novel 2-aryl-4-benzoyl-imidazoles targeting the colchicines binding site in tubulin as potential anticancer agents  

OpenAIRE

A series of 2-aryl-4-benzoyl-imidazoles (ABI) was synthesized as a result of structural modifications based on the previous set of 2-aryl-imidazole-4-carboxylic amide (AICA) derivatives and 4-substituted methoxylbenzoyl-aryl-thiazoles (SMART). The average IC50 of the most active compound (5da) was 15.7 nM. ABI analogs have substantially improved aqueous solubility (48.9 ?g/mL for 5ga vs. 0.909 ?g/mL for SMART-1, 0.137 ?g/mL for paclitaxel, and 1.04 ?g/mL for Combretastatin A4). Mechanism ...

Chen, Jianjun; Wang, Zhao; Li, Chien-ming; Lu, Yan; Vaddady, Pavan K.; Meibohm, Bernd; Dalton, James T.; Miller, Duane D.; Li, Wei

2010-01-01

122

Synthesis, antimicrobial, and anti-inflammatory activity, of novel S-substituted and N-substituted 5-(1-adamantyl)-1,2,4-triazole-3-thiols  

Science.gov (United States)

The reaction of 5-(1-adamantyl)-4-phenyl-1,2,4-triazoline-3-thione (compound 5) with formaldehyde and 1-substituted piperazines yielded the corresponding N-Mannich bases 6af. The reaction of 5-(1-adamantyl)-4-methyl-1,2,4-triazoline-3-thione 8 with various 2-aminoethyl chloride yielded separable mixtures of the S-(2-aminoethyl) 9ad and the N-(2-aminoethyl) 10ad derivatives. The reaction of compound 5 with 1-bromo-2-methoxyethane, various aryl methyl halides, and ethyl bromoacetate solely yielded the S-substituted products 11, 12ad, and 13. The new compounds were tested for activity against a panel of Gram-positive and Gram-negative bacteria and the pathogenic fungus Candida albicans. Compounds 6b, 6c, 6d, 6e, 6f, 10b, 10c, 10d, 12c, 12d, 12e, 13, and 14 displayed potent antibacterial activity. Meanwhile, compounds 13 and 14 produced good dose-dependent anti-inflammatory activity against carrageenan-induced paw edema in rats. PMID:24872681

Al-Abdullah, Ebtehal S; Asiri, Hanadi H; Lahsasni, Siham; Habib, Elsayed E; Ibrahim, Tarek M; El-Emam, Ali A

2014-01-01

123

SYNTHESIS AND ANTIMICROBIAL EVALUATION OF 2-(4-FLUORO BENZYLTHIO-N-(SUBSTITUTED PHENYLPYRIMIDINE-4-AMINES  

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Full Text Available Reaction of 4-fluorobenzylchloride with 2-thiouracil (1 gave 2-(4-fluorobenzylthiopyrimidin-4(3H-one (2, which on chlorination with POCl3 furnished 4-chloro-2-(4-fluorobenzylthio-4-chloropyrimidine (3. This intermediate when treated with various substituted anilines gave desired targeted compounds 4(a-k in 50-90% yield. Structural assignments of the synthesized compounds were based on their IR, 1H NMR, Mass and analytical data. The antimicrobial evaluation of newly synthesized compounds was carried out by cup-plate method. The investigation of antimicrobial screening reveals that the compounds 4b, 4g, 4c and 4f showed good activity against bacterial strain B. subtilis. Compounds 4a, 4e, 4b, 4c, 4f, 4g and 4h were active against bacterial strain P. aeruginosa. Compounds 4a and 4c were active against fungul strain A. niger. Compounds 4e, 4b and 4j showed good activity against fungal strain A. flavus. All the synthesized compounds showed excellent antifungal activity against T.viridae. Remaining compounds exhibited moderate to poor activity against bacterial and fungal strains when compared to standard drugs Gentamycin and Fluconazole respectively. So, further we have carried out the antifungal screening of all the synthesized compounds at different concentrations against T. viridae to determine their IC50 values. Compounds 4e, 4b, 4g, 4i, 4d, 4f and 4j have shown better IC50 values.

N.M. Goudgaon*, Y. Rohini Reddy and B.U. Sheshikant

2013-11-01

124

A Facile Synthesis of N-H- and N-Substituted Acridine-1,8-diones under Sonic Condition  

OpenAIRE

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.

Sudha, S.; Pasha, M. A.

2013-01-01

125

Highly regio- and enantioselective synthesis of N-substituted 2-pyridones: iridium-catalyzed intermolecular asymmetric allylic amination.  

Science.gov (United States)

The first iridium-catalyzed intermolecular asymmetric allylic amination reaction with 2-hydroxypyridines has been developed, thus providing a highly efficient synthesis of enantioenriched N-substituted 2-pyridone derivatives from readily available starting materials. This protocol features a good tolerance of functional groups in both the allylic carbonates and 2-hydroxypyridines, thereby delivering multifunctionalized heterocyclic products with up to 98?% yield and 99?%?ee. PMID:25504907

Zhang, Xiao; Yang, Ze-Peng; Huang, Lin; You, Shu-Li

2015-02-01

126

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

OpenAIRE

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.

Di Gennaro, Patrizia; Colmegna, Andrea; Galli, Enrica; Sello, Guido; Pelizzoni, Francesca; Bestetti, Giuseppina

1999-01-01

127

compounds  

Science.gov (United States)

Size is the key factor of nanostructured materials, since all the structural, transport, electrical, magnetic and other physical properties can be tuned by this factor of materials. Only the condition is to choose appropriate inexpensive scale-processing method for material synthesis which offers good control over the stoichiometry, morphology and particle size distribution. Present communication deals with the studies on the sol-gel grown Y0.95Ca0.05MnO3 (YCMO) nanostructured compounds for their size-induced tuning of dielectric behavior. Structural studies reveal the single phasic nature with improved crystallite size with sintering temperature. Dielectric constant (real and imaginary) is found to increase with temperature and crystallite size/sintering temperature. High dielectric loss has been observed in the present system. Size dependent activation energy ( E a), obtained from modulus measurement, showing the increase in E a with crystallite size. The variation in various dielectric parameters and E a has been discussed in the light of crystallite size, crystallite boundaries, oxygen vacancies and charge carrier hopping.

Shah, N. A.

2014-10-01

128

Effects of pesticide compounds (chlorothalonil and mancozeb) and benzo[a]pyrene mixture on aryl hydrocarbon receptor, p53 and ubiquitin gene expression levels in haemocytes of soft-shell clams (Mya arenaria).  

Science.gov (United States)

The aim of this study is to investigate the effects of the pesticides/polycyclic aromatic hydrocarbon mixture on aryl hydrocarbon receptor (AhR), p53 and ubiquitin mRNA level in haemocytes of Mya arenaria exposed to a mixture of chlorothalonil, mancozeb and benzo[a]pyrene (BaP) for 48 and 72 h. AhR, p53 and ubiquitin gene expression levels were quantified using quantitative Real-time PCR. For robust and accurate quantification of transcripts, suitable housekeeping genes were selected from four sets of ribosomal and elongation factors transcripts previously sequenced from Mya arenaria using geNorm open source software. Quantitative Real-time PCR data exhibited a significantly high expression of AhR after 72 h of exposure (P ? 0.05). p53 gene expression seems to be up-regulated by the mixture after 48 h, however not significantly; but the level of p53 mRNA is down-regulated by the xenobiotics between 48 and 72 h after exposure. This study postulates that AhR mRNA levels could be used as an indicator of the exposure of clams' haemocytes to a mixture of xenobiotics such as chlorothalonil, mancozeb and BaP. However, further studies have to be pursued in order to unravel the molecular mechanisms involved in the p53 signaling pathway. PMID:21688059

Pariseau, Julie; McKenna, Patricia; Aboelkhair, Mohammed; Saint-Louis, Richard; Pelletier, Emilien; Davidson, T Jeffrey; Tremblay, Rjean; Berthe, Franck C J; Siah, Ahmed

2011-11-01

129

Asymmetric intermolecular Heck reaction of aryl halides.  

Science.gov (United States)

The asymmetric intermolecular Heck reaction has been limited to aryl and vinyl triflates. Herein, we extend the reaction to aryl and vinyl bromides. Various cyclic olefins coupled with high enantioselectivity. Only bisphosphine oxides on a spiro backbone formed highly stereoselective Pd catalysts. The use of alcoholic solvents and alkylammonium salts were essential to promote halide dissociation from neutral arylpalladium complexes. PMID:24383764

Wu, Chunlin; Zhou, Jianrong Steve

2014-01-15

130

Palladium-Catalyzed Carbonylative ?-Arylation to ?-Ketonitriles  

DEFF Research Database (Denmark)

A carbonylative ?-arylation process employing unactivated nitriles for the first time is described. The reaction tolerates a range of (hetero)aryl iodides and several nitrile coupling partners. No prefunctionalization of the nitriles is necessary and the resulting ?-ketonitriles are obtained in good to excellent yields. The methodology also allows for a convenient (13) C-labelling of the generated carbonyl moiety.

Schranck, Johannes; Burhardt, Mia

2014-01-01

131

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

132

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

Directory of Open Access Journals (Sweden)

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

133

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

134

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

2014-07-14

135

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

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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

136

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

137

Development of N-substituted quinolinimides, as potential PET tracers for the visualisation of ?-opioid receptors  

International Nuclear Information System (INIS)

In order to develop radiotracers for in vivo studies of ?-opioid receptors by Positron Emission Tomography (PET) or Single Photon Emission computed Tomography (SPECT), we undertook the synthesis of halogenated analogues (chlorinated and brominated) of compound 12. These analogues were prepared by a convergent synthesis and from these novel structures a halogen exchange reaction has been performed to complete this series. These molecules were tested to determine their in vitro affinity and selectivity toward ? opioid receptors. The compounds 12 and 15 were labelled with carbon-11. The radiosynthesis of compound 12, in weak radioactivity chemistry, was performed first by the Stille reaction and second by a new methodology based on the transfer reaction of [11C]-methyl group. This new methodology used a mono-organotin compound prepared by addition of [11C]-iodomethane onto Lappert's stannylene. The compound [11C]-12 was obtained with 60 and 10% radiochemical yield respectively. In order to produce higher radioactivity quantities, the Stille reaction was automated. The compounds [11C]-12 and [11C]-15 were obtained in 40 minutes with a specific radioactivity ranging from 322 to 747 mCi/?mol. (author)

138

Antileishmanial, Antimicrobial and Antifungal Activities of Some New Aryl Azomethines  

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Full Text Available A series of eighteen azomethines has been synthesized by the reaction of appropriate primary aromatic amines with aryl and/or heteroaryl carboxaldehydes. The synthesized azomethines have been evaluated for their in vitro antileishmanial, antibacterial and antifungal activities. The results revealed some antifungal activity of most of the synthesized compounds, whereas the antileishmaniasis activity results highlighted that all synthesized azomethines inhibited parasite growth and most of them showed highly potent action towards Leishmania major promastigotes. No remarkable bactericidal activities were observed.

Masoom Yasinzai

2010-01-01

139

Testing for partial agonism of the aryl hydrocarbon receptor  

OpenAIRE

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is the most potent of a group of persistent organic pollutants (POPs). The aryl hydrocarbon receptor (AhR) has a high affinity for these dioxin-like compounds with activation increasing transcription of CYP1A1. The aim of this paper was to measure the agonistic and potential antagonistic effects of four of the most prevalent and potent dioxin-like agonists: 3-Methylcholanthrene (3-MC), 2,3,7,8-Tetrachlorodibenzofuran (TCDF), 2,3,4,7,8-Pentachlorodibe...

Wall, Richard J.

2008-01-01

140

Nickel-Catalyzed Amination of Aryl Chlorides and Sulfamates in 2-Methyl-THF.  

Science.gov (United States)

The nickel-catalyzed amination of aryl O-sulfamates and chlorides using the green solvent 2-methyl-THF is reported. This methodology employs the commercially available and air-stable precatalyst NiCl2(DME), is broad in scope, and provides access to aryl amines in synthetically useful yields. The utility of this methodology is underscored by examples of gram-scale couplings conducted with catalyst loadings as low as 1 mol % nickel. Moreover, the nickel-catalyzed amination described is tolerant of heterocycles and should prove useful in the synthesis of pharmaceutical candidates and other heteroatom-containing compounds. PMID:25243095

Fine Nathel, Noah F; Kim, Junyong; Hie, Liana; Jiang, Xingyu; Garg, Neil K

2014-09-01

141

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

142

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

143

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

144

Synthesis, structure, and stability of diiodobromides of N-substituted isoquinolinium derivatives  

International Nuclear Information System (INIS)

Diidobromides of N-propylisoquinolinium (1) and 1-amino-N-p-chlorobenzeneisoquinolinium (2) were synthesized. Influence of the cation structure on stability of the compounds in chloroform solution was estimated. According to X-ray diffraction analysis data crystal structure of compound 1 is formed by cations of N-propylisoquinolinium and anions I2Br-, their structure depicted by the formula I20.5Br20.5-I1-I30.5Br30.5. In the above-mentioned anions the I-Br distances equal 2.820(2) A and 2.822(2) A, while valency angle amount to 175.51(5) Deg. Kinetics of disproportionation reactions of compounds 1 and 2 in alcohols, acetonitrile and diethyl ether was studied

145

2-(Hetero(aryl)methylene)hydrazine-1-carbothioamides as Potent Urease Inhibitors.  

Science.gov (United States)

A small series of 2-(hetero(aryl)methylene) hydrazine-1-carbothioamides including two aryl derivatives was synthesized and tested for their inhibitory activity against urease. Compound (E)-2-(Furan-2-ylmethylene) hydrazine-1-carbothioamide (3f), having a furan ring, was the most potent inhibitor of urease with an IC50 value of 0.58?m. Molecular modeling was carried out through docking the designed compounds into the urease binding site to predict whether these derivatives have analogous binding mode to the urease inhibitors. The study revealed that all of the tested compounds bind with both metal atoms at the active site of the enzyme. The aromatic ring of the compounds forms ionic interactions with the residues, Ala(440), Asp(494), Ala(636), and Met(637). PMID:24938644

Saeed, Aamer; Imran, Aqeel; Channar, Pervaiz A; Shahid, Mohammad; Mahmood, Wajahat; Iqbal, Jamshed

2015-02-01

146

Novel hybrids of natural isochroman-4-one bearing N-substituted isopropanolamine as potential antihypertensive candidates.  

Science.gov (United States)

A series of novel hybrids of natural isochroman-4-one bearing isopropanolamine moiety were designed, synthesized and evaluated for their antihypertensive activity. It was found that compound IIId, prepared by hybridizing N-isopropyl substituted isopropanolamine functionality to a phenolic oxygen of isochroman-4-one, exhibited potent ?(1)-adrenoceptor blocking effect comparable to the well-known antihypertensive drug propranolol. Additionally, IIId significantly reduced the systolic and diastolic blood pressure in SHRs by over 40%, which was obviously stronger than the lead compounds 7,8-dihydroxy-3-methyl-isochroman-4-one (XJP) and its analogue XJP-B. Overall, IIId may be a promising antihypertensive candidate for further investigation. PMID:23538234

Bai, Renren; Huang, Xiaojing; Yang, Xue; Hong, Wen; Tang, Yiqun; Yao, Hequan; Jiang, Jieyun; Liu, Jie; Shen, Mingqin; Wu, Xiaoming; Xu, Jinyi

2013-05-01

147

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

148

The ketene-surrogate coupling: catalytic conversion of aryl iodides into aryl ketenes through ynol ethers.  

Science.gov (United States)

tert-Butoxyacetylene is shown to undergo Sonogashira coupling with aryl iodides to yield aryl-substituted tert-butyl ynol ethers. These intermediates participate in a [1,5]-hydride shift, which results in the extrusion of isobutylene and the generation of aryl ketenes. The ketenes are trapped in situ with multiple nucleophiles or undergo electrocyclic ring closure to yield hydroxynaphthalenes and quinolines. PMID:24975840

Zhang, Wenhan; Ready, Joseph M

2014-08-18

149

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

OpenAIRE

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; Dahua Shi; Yingying Qu; Chuanzhou Tao; Weiwei Liu; Guowei Yao

2013-01-01

150

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

151

Identification of 2-amino-5-aryl-pyrazines as inhibitors of human lactate dehydrogenase.  

Science.gov (United States)

A 2-amino-5-aryl-pyrazine was identified as an inhibitor of human lactate dehydrogenase A (LDHA) via a biochemical screening campaign. Biochemical and biophysical experiments demonstrated that the compound specifically interacted with human LDHA. Structural variation of the screening hit resulted in improvements in LDHA biochemical inhibition and pharmacokinetic properties. A crystal structure of an improved compound bound to human LDHA was also obtained and it explained many of the observed structure-activity relationships. PMID:24012183

Fauber, Benjamin P; Dragovich, Peter S; Chen, Jinhua; Corson, Laura B; Ding, Charles Z; Eigenbrot, Charles; Giannetti, Anthony M; Hunsaker, Thomas; Labadie, Sharada; Liu, Yichin; Liu, Yingchun; Malek, Shiva; Peterson, David; Pitts, Keith; Sideris, Steve; Ultsch, Mark; VanderPorten, Erica; Wang, Jing; Wei, BinQing; Yen, Ivana; Yue, Qin

2013-10-15

152

Synthesis and dynamic stereochemistry of 4-aryl-thiomorpholine-3,5-dione derivatives  

Science.gov (United States)

A series of new N-aryl-substituted thiomorpholine-3,5-diones were synthesized. Crystal structures of seven compounds were established on the basis of X-ray crystallography. Stable at room temperature diastereomers were detected for (2-phenyl)-substituted derivatives using 1H NMR. The dynamic stereochemistry of compound 36 was studied with variable-temperature 1H NMR and the mechanism of diastereomers interconversion was proposed on the basis of quantum chemical calculations.

Szawka?o, Joanna; Maurin, Jan K.; Pluci?ski, Franciszek; Czarnocki, Zbigniew

2015-01-01

153

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese N,N',N'',N'''-Tetrametil tetra(2,3-piridil)porfirazinato metil sulfato de cobre(II) ([Cu(2,3-tmtppa)](MeSO4)4) catalisou com sucesso a converso direta de nitrilas a amidas N-substitudas. A sntese seletiva do tipo one pot de amidas N-substitudas a partir de nitrilas e aminas primrias foi realiza [...] da em refluxo de gua. O catalisador foi recuperado e reusado no mnimo 4 vezes, mantendo a sua eficincia. Abstract in english 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.

Sara S. E., Ghodsinia; Batool, Akhlaghinia; Elham, Safaei; Hossein, Eshghi.

2013-06-01

154

Discovery of novel N-substituted carbazoles as neuroprotective agents with potent anti-oxidative activity.  

Science.gov (United States)

Carbazole moiety is an important scaffold with a variety of biological applications, for example, anti-oxidative stress. Our previous synthesized carbazoles were screened for their neuroprotective properties against two individual oxidative stresses. Some of the new carbazole derivatives were observed with modest to good neuroprotective effects on neuronal cells HT22 against cell injury induced by glutamate or homocysteic acid (HCA). Substituents introduced to the carbazole ring system play crucial roles in their biological activities. In particular, a bulky group favors the neuroprotective activity of the compounds. One of the new compounds, 6, showed the best neuroprotective effects, which might result from its anti-oxidative activity with a GSH-independent mechanism. These findings might provide an alternative strategy for the development of novel carbazole derivatives for the treatment of CNS diseases such as Alzheimer's disease. PMID:23973819

Zhu, Daqian; Chen, Meihui; Li, Min; Luo, Bingling; Zhao, Yang; Huang, Peng; Xue, Fengtian; Rapposelli, Simona; Pi, Rongbiao; Wen, Shijun

2013-10-01

155

Synthesis of N-substituted phthalimidoalkyl 1,2,3-triazoles via click chemistry  

OpenAIRE

In the present work, we have developed a facile procedure for synthesis of new N-phthalimidoalkyl 1H-1,2,3-Triazoles (1-4)(a-h) using DMF, 10 mol% CuI, Et3N and ultrasound energy at room temperature. This protocol furnished 28 new compounds in 20 to 30 min of reaction and moderate-to-excellent yields (64-94%).

Da Silva, Moara T.; Oliveira, Ronaldo N.

2012-01-01

156

An easy direct arylation of 5-pyrazolones  

Science.gov (United States)

Summary A mild, efficient and catalytic ligand-free method for the direct arylation of 5-pyrazolones by Pd-catalyzed CH bond activation is reported. The process smoothly proceeds and yields are moderate to excellent. PMID:24204415

Gong, Hao; Yang, Yiwen; Wang, Zechao

2013-01-01

157

Detection of Aryl Radicals in Hydrodediazoniations.  

Science.gov (United States)

Iodoacetic acid, an effective aryl radical trapping agent, was employed to investigate the reactive intermediates in several hydrodediazoniations. Isolation of an aryl iodide constitutes a positive result in the test for aryl radicals. Equally as important is the lower yield of the reduction product when the trap diverts radicals from their usual reaction path. Hydrodediazoniations performed in MeOH, EtOH, i-PrOH, benzyl alcohol, THF, tetramethylurea, formamide, and hypophosphorous acid all involve aryl radical intermediates. Ferrocene was found to be an effective initiator in most of these reactions; through its action as an electron donor, it serves to shorten reaction times and to improve yields of hydrodediazoniation products. All hydrodediazoniations examined, whether initiated or not, involve radical intermediates. PMID:11671965

Wassmundt, Frederick W.; Kiesman, William F.

1997-11-28

158

Silver-mediated fluorination of aryl silanes  

OpenAIRE

A regiospecific silver-mediated fluorination of aryl silanes is reported. The reaction is operationally simple, and employs Ag2O as readily available, inexpensive silver source, which can be recovered.

Tang, Pingping; Ritter, Tobias

2011-01-01

159

Synthesis of N-aryl-N'-[2-phenyl-3-quinazoline(3H)-4-one] acylthiourea derivatives as anticonvulsants.  

Science.gov (United States)

By the reaction of [2-phenyl-3-quinazolineo (3H)-4-one] acyl isothiocynates and appropriate aryl amines in acetone, 24 new compounds, having a substituted thiourea grouping at the 3-position of the quianozolone moiety, were prepared. All compounds, except two, showed different degree of protection against pentetrazol induced seizures test in albino mice. While studying the effect of structural variation no definite pattern could be observed due to variations in 1-aryl moiety, but it was noticed that generally the branching or lengthening of 3-acyl chain either diminishes or does not effect the activity. PMID:493181

Misra, V S; Pandey, R N; Dua, P R

1979-01-01

160

Synthesis, Characterization, Thermal and Antimicrobial studies of N-substituted Sulfanilamide derivatives  

Science.gov (United States)

Four sulfanilamide derivatives N-[4-(phenylsulfamoyl)phenyl]acetamide (1), 4-amino-N-phenylbenzenesulfonamide (2),N-[4-(phenylsulfamoyl)phenyl]benzamide (3) and N-{4-[(3-chlorophenyl)sulfamoyl]phenylbenzamide (4) were synthesized and characterized by Infra-Red (IR), Nuclear Magnetic Resonance (NMR) and UV-visible (UV-Vis) spectra. Also Liquid Chromatographic (LCMS) and High Resolution Mass Spectrometric (HRMS) methods were used. Crystal structures of 1-4 were determined by single crystal X-ray diffraction (XRD) and their conformational and hydrogen bond (HB) network properties were examined with survey of the literature data. Compounds 1 and 2 crystallize in the same orthorhombic Pbca symmetry with equivalent molecular conformation (tilted V-shape) but showed distinct packing and hydrogen bonding models. Compounds 3 and 4 crystallize in monoclinic and triclinic crystal systems, albeit exhibiting identical molecular conformation (L-shaped). Same donor acceptor pairs both on 3 and 4 result to different kind of HB network. Thermogravimetric (TG) and differential scanning calorimetric (DSC) methods were used to evaluate thermal properties of the substances. All sulfanilamide derivatives have melting points between195-227 C, initiation of thermal decomposition between 259-271 C and enthalpies of fusion ?HfusT = 38.96, 36.60, 46.23 and 44.81 kJ mol-1 were determined for 1-4, respectively. The derivatives were screened for their antibacterial and antifungal activities against various bacterial and fungal strains. It is observed that there is no significant antibacterial activity with the introduction of the benzene ring to CO-NH group or SO2-NH moiety, and none of the compounds exhibited antifungal activity.

Lahtinen, Manu; Kudva, Jyothi; Hegde, Poornima; Bhat, Krishna; Kolehmainen, Erkki; Nonappa; Venkatesh; Naral, Damodara

2014-02-01

161

Synthesis and anti-leishmanial activity of 1-aryl-?-carboline derivatives against Leishmania donovani.  

Science.gov (United States)

?-carbolines from various natural and synthetic sources have been known to show diverse biological activities. As a part of our current ongoing project to search for potent natural product-derived anti-leishmanial compounds, we have synthesized a series of substituted 1-aryl-?-carboline derivatives. A total of 22 compounds were synthesized and tested in vitro against Leishmania donovani, out of which 6 compounds (4, 5, 10, 11, 19 and 22) showed notably more activity than the standard miltefosine (IC(50) 12.070.82 ?M), with compound 4 being the most potent (IC(50) 2.160.26 ?M). PMID:22608390

Gohil, Vikrantsinh M; Brahmbhatt, Keyur G; Loiseau, Philippe M; Bhutani, Kamlesh K

2012-06-15

162

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

Science.gov (United States)

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 amorphous thin films whereas films of NBI-TAA-Oc are highly crystalline. DFT calculations predict the ionization potential (IP) of 5.22 eV and 5.18 eV for NBI-TAA-Oc and NBI-(TAA)(2), respectively, as well as the electron affinity values (EA) of -3.25 eV and -3.22 eV. These results are consistent with the cyclic voltammetry data which yield similar values of IP (5.20 eV and 5.19 eV) and somehow different values of EA (-3.80 eV and -3.83 eV). As judged from these data, both semiconductors should exhibit ambipolar behavior. Indeed, NBI-TAA-Oc is ambipolar, showing hole and electron mobilities of 4.5 10(-5) cm(2)/(V s) and of 2.6 10(-4) cm(2)/(V s), respectively, in the field effect transistor configuration. NBI-(TAA)(2) is not ambipolar and yields field effect only in the p-channel configuration. This different behavior is rationalized on the basis of structural factors. PMID:23243662

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

2013-02-01

163

Modulated protonation of side chain aminoethylene repeats in N-substituted polyaspartamides promotes mRNA transfection.  

Science.gov (United States)

Fine-tuning of chemical structures of polycation-based carriers (polyplexes) is an attractive strategy for safe and efficient mRNA transfaction. Here, mRNA polyplexes comprising N-substituted polyaspartamides with varied numbers of side chain aminoethylene repeats were constructed, and their transfection ability against human hepatoma cells was examined. Transfection efficacy clearly correlated with the number of aminoethylene repeats: polyplexes with odd number repeats (PA-Os) produced sustained increases in mRNA expression compared with those with even number repeats (PA-Es). This predominant efficacy of PA-Os over PA-Es was contradictory to our previous findings for pDNA polyplexes prepared from the same N-substituted polyaspartamides, that is, PA-Es revealed superior transfection efficacy of pDNA than PA-Os. Intracellular FRET analysis using flow cytometry and polyplex tracking under confocal laser scanning microscopy revealed that overall transfection efficacy was determined through the balance between endosomal escaping capability and stability of translocated mRNA in cytoplasm. PA-Es efficiently transported mRNA into the cytoplasm. However, their poor cytoplasmic stability led to facile degradation of mRNA, resulting in a less durable pattern of transfection. Alternatively, PA-Os with limited capability of endosomal escape eventually protect mRNA in the cytoplasm to induce sustainable mRNA expression. Higher cytoplasmic stability of pDNA compared to mRNA may shift the limiting step in transfection from cytoplasmic stability to endosomal escape capacity, thereby giving an opposite odd-even effect in transfection efficacy. Endosomal escaping capability and nuclease stability of polyplexes are correlated with the modulated protonation behavior in aminoethylene repeats responding to pH, appealing the substantial importance of chemistry to design polycation structures for promoted mRNA transfection. PMID:25133991

Uchida, Hirokuni; Itaka, Keiji; Nomoto, Takahiro; Ishii, Takehiko; Suma, Tomoya; Ikegami, Masaru; Miyata, Kanjiro; Oba, Makoto; Nishiyama, Nobuhiro; Kataoka, Kazunori

2014-09-01

164

Antioxidant properties of (R)-Se-aryl thiazolidine-4-carboselenoate.  

Science.gov (United States)

The antioxidant potential of organoselenium compounds has been extensively investigated because oxidative stress is a hallmark of a variety of human diseases. In this study, we report the influence of substituent groups on the antioxidant activity of (R)-Se-aryl thiazolidine-4-carboselenoate (Se-PTC) in several in vitro assays. The amino group in the thiazolidine ring affects the antioxidant activity of the compound. Our data revealed that Se-PTC a had higher radical scavenging efficiency in the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS(+)) assays compared to other compounds. In the ferric ion reducing antioxidant power (FRAP) assay, Se-PTC a exhibited ferric-reducing ability at concentrations as low as 5?M. However, this effect was diminished when the amino group was protected with carbamate (Se-PTC d). In the nitric oxide scavenging assay, Se-PTC c presented better NO-scavenging than Se-PTC b. However, Se-PTC a and d did not prevent NO formation at any of the tested concentrations. Se-PTC c decreased the sodium nitroprussate-induced lipid peroxidation in the cortex and hippocampus of mice. In summary, we demonstrate that Se-PTC is a promising antioxidant compound and that the compound's activity is influenced by the amino group and by the characteristics of the arylselenium substituents. Thus, these compounds may be used as synthetic antioxidants that provide protection against oxidative diseases. PMID:23830813

Victoria, Francine Novack; Martinez, Dbora Martins; Castro, Micheli; Casaril, Angela M; Alves, Diego; Lenardo, Eder Joo; Salles, Helena Domingues; Schneider, Paulo H; Savegnago, Lucielli

2013-09-25

165

Discovery and SARs of Trans-3-Aryl Acrylic Acids and Their Analogs as Novel Anti- Tobacco Mosaic Virus (TMV) Agents  

OpenAIRE

A series of trans-3-aryl acrylic acids 127 and their derivatives 2834 were prepared and evaluated for their antiviral activity against tobacco mosaic virus (TMV) for the first time. The bioassay results showed that most of these compounds exhibited good antiviral activity against TMV, of which compounds 1, 5, 6, 20, 27 and 34 exhibited significantly higher activity against TMV than commercial Ribavirin both in vitro and in vivo. Furthermore, these compounds have more simple structure th...

Wu, Meng; Wang, Ziwen; Meng, Chuisong; Wang, Kailiang; Hu, Yanna; Wang, Lizhong; Wang, Qingmin

2013-01-01

166

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

167

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

OpenAIRE

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; Zhongjun Li; Renna Luo; Gaoyun Hu; Qi Hou; Zhiqi Lao; Lingling Xuan; Jinye Bai; Xiangbao Meng; Qinghua Lou

2012-01-01

168

The Remarkable Reactivity of Aryl Halides with Nucleophiles  

Science.gov (United States)

Discusses the reactivity of aryl halides with nucleophilic or basic reagents, including nucleophilic attacks on carbon, hydrogen, halogen, and arynes. Suggestions are made concerning revisions of the sections on aryl halide chemistry courses and the corresponding chapters in textbooks. (CC)

Bunnett, Joseph F.

1974-01-01

169

Photocatalytic Arylation of Alkenes, Alkynes and Enones with Diazonium Salts  

OpenAIRE

Teaching old dogs new tricks: Visible light photoredox catalysis improves the classic Meerwein arylation protocol significantly and allows the light-controlled arylation of alkenes, alkynes and enones by diazonium salts.

Schroll, Peter; Hari, Durga Prasad; Ko?nig, Burkhard

2012-01-01

170

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

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

2006-09-01

171

Smiles Rearrangement Based Practical One-pot Synthesis of N-Alkyl/aryl-6-aminoquinolines from 6-Hydroxylquinoline  

Energy Technology Data Exchange (ETDEWEB)

The C-N coupling protocol reported herein represents a convenient and practical synthesis of N-alkyl/aryl-6-aminoquinolines in a three-step one-pot manner by simple addition of 6-hydroxyquinoline and N-alkyl/aryl-2-chloroacetamides with Cs{sub 2}CO{sub 3} or K{sub 2}CO{sub 3} in DMF at 150 .deg. C via Smiles rearrangement. An electron donating substituent on the nitrogen counterpart would accelerate the rearrangement process to achieve various anilines in good yields. We currently engaged in making a chemical library including multifarious N-substituted-6-aminoquinolines, to be used in the screening for specific AChEI activity. Furthermore, this work extends the scope of preparing different heterocyclic synthons in drug design for various biological activities. Aminoquinolines and their derivatives are important chemical entities that are widely used as pro-drugs and drugs due to their antimicrobial, cytotoxic and anti-malarial activities etc.

Xie, Yongsheng; Vijaykumar, B. V. D.; Jang, Kiwan; Choi, Kyungmin; Shin, Dongsoo [Changwon National Univ., Changwon (Korea, Republic of); Zuo, Hua [Southwest Univ., Chongqing (Korea, Republic of); Yoon, Yongjin [Gyeongsang National Univ., Chinju (Korea, Republic of)

2013-12-15

172

Interaction of an extended series of N-substituted di(2-picolyl)amine derivatives with copper(II). Synthetic, structural, magnetic and solution studies.  

Science.gov (United States)

The interaction of Cu(II) with the following secondary N-substituted derivatives of di(2-picolyl)amine () are reported: N-cyclohexylmethyl-di(2-picolyl)amine (), N-benzyl-di(2-picolyl)amine (), N-(4-pyridylmethyl)-di(2-picolyl)amine (), N-(4-carboxymethylbenzyl)-di(2-picolyl)amine (), N-(9-anthracen-8-ylmethyl)-di(2-picolyl)amine (), 1,3-bis[di(2-picolyl)aminomethyl]benzene (), 1,4-bis[di(2-picolyl)aminomethyl]benzene () and 2,4,6-tris[di(2-picolyl)amino]triazine (). The solid complexes [Cu()(micro-Cl)](2)(PF(6))(2), [Cu()(micro-Cl)](2)(PF(6))(2).0.5CH(2)Cl(2), Cu()(ClO(4))(2), Cu()(2)(ClO(4))(2), [Cu()(ClO(4))(2)(H(2)O)].0.5H(2)O, Cu(2)()(ClO(4))(4), [Cu(2)()(Cl)(4)] and [Cu(2)(+H)(micro-OCH(3))(2)(H(2)O)](ClO(4))(3).C(4)H(10)O were isolated and X-ray structures of [Cu()(micro-Cl)](2)(PF(6))(2), [Cu()(micro-Cl)](2)(PF(6))(2).0.5CH(2)Cl(2,) [Cu()(2)(ClO(4))(2)(H(2)O)].0.5H(2)O, [Cu(2)()Cl(4)] and [Cu(2)(+H)(micro-OCH(3))(2)(H(2)O)](ClO(4))(3).C(4)H(10)O were obtained. The series is characterised by a varied range of coordination geometries and lattice architectures which in the case of [Cu()(ClO(4))(2)(H(2)O)].0.5H(2)O includes a chain-like structure formed by unusual intermolecular pi-interactions between metal bound perchlorate anions and the aromatic rings of adjacent anthracenyl groups. Variable temperature magnetic susceptibility measurements have been performed for [Cu()(micro-Cl)](2)(PF(6))(2) and [Cu()(micro-Cl)](2)(PF(6))(2).0.5H(2)O over the range 2-300 K. Both compounds show Curie-Weiss behaviour, with the data indicating weak antiferromagnetic interaction between the pairs of copper ions in each complex. Liquid-liquid (H(2)O/CHCl(3)) extraction experiments involving and as extractants showed that, relative to the parent (unsubstituted) dipic ligand , substitution at the secondary amine site in each case resulted in an increase in extraction efficiency towards Cu(II) (as its perchlorate salt); at least in part, this increase may be attributed to the enhanced lipophilicities of the N-substituted derivatives. PMID:19513491

Antonioli, Bianca; Bchner, Bernd; Clegg, Jack K; Gloe, Kerstin; Gloe, Karsten; Gtzke, Linda; Heine, Axel; Jger, Anne; Jolliffe, Katrina A; Kataeva, Olga; Kataev, Vladislav; Klingeler, Rdiger; Krause, Tilo; Lindoy, Leonard F; Popa, Andreia; Seichter, Wilhelm; Wenzel, Marco

2009-06-28

173

Palladium-catalysed arylative cyclisation of N-allylacetamides with aryl halides yielding benzyl-substituted oxazolines.  

Science.gov (United States)

Treatment of N-allylacetamide with aryl halide in the presence of sodium t-butoxide and a palladium catalyst leads to arylative cyclisation to provide the corresponding benzyl-substituted oxazoline in high yield. PMID:19774259

Fujino, Daishi; Hayashi, Sayuri; Yorimitsu, Hideki; Oshima, Koichiro

2009-10-14

174

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

175

Discovery of aryl ureas and aryl amides as potent and selective histamine H3 receptor antagonists for the treatment of obesity (part I).  

Science.gov (United States)

A series of structurally novel aryl ureas was derived from optimization of the HTS lead as selective histamine H3 receptor (H3R) antagonists. The SAR was explored and the data obtained set up the starting point and foundation for further optimization. The most potent tool compounds, as exemplified by compounds 2l, 5b, 5d, and 5e, displayed antagonism potencies in the subnanomolar range in in vitro human-H3R FLIPR assays and rhesus monkey H3R binding assays. PMID:23591110

Gao, Zhongli; Hurst, William J; Guillot, Etienne; Czechtizky, Werngard; Lukasczyk, Ulrike; Nagorny, Raisa; Pruniaux, Marie-Pierre; Schwink, Lothar; Sanchez, Juan Antonio; Stengelin, Siegfried; Tang, Lei; Winkler, Irvin; Hendrix, James A; George, Pascal G

2013-06-01

176

3-Amido-3-aryl-piperidines: A Novel Class of Potent, Selective, and Orally Active GlyT1 Inhibitors.  

Science.gov (United States)

3-Amido-3-aryl-piperidines were discovered as a novel structural class of GlyT1 inhibitors. The structure-activity relationship, which was developed, led to the identification of highly potent compounds exhibiting excellent selectivity against the GlyT2 isoform, drug-like properties, and in vivo activity after oral administration. PMID:24900853

Pinard, Emmanuel; Alberati, Daniela; Alvarez-Sanchez, Ruben; Brom, Virginie; Burner, Serge; Fischer, Holger; Hauser, Nicole; Kolczewski, Sabine; Lengyel, Judith; Mory, Roland; Saladin, Christian; Schulz-Gasch, Tanja; Stalder, Henri

2014-04-10

177

Enantioselective alpha-arylation of ketones with aryl triflates catalyzed by difluorphos complexes of palladium and nickel.  

Science.gov (United States)

The asymmetric alpha-arylation of ketones with aryl triflates is described, and the use of this electrophile with nickel and palladium catalysts containing a segphos derivative increases substantially the scope of highly enantioselective arylations of ketone enolates. The combination of aryl triflates as reactant, difluorphos as ligand, palladium catalysts for reactions of electron-neutral or electron-rich aryl triflates, and nickel catalysts for reactions of electron-poor aryl triflates led to a series of alpha-arylations of tetralone, indanone, cyclopentanone, and cyclohexanone derivatives. Enantioselectivities ranged from 70% to 98% with 10 examples over 90%. Systematic studies on these alpha-arylations have revealed a number of factors that affect enantioselectivity. Ligands containing biaryl backbones with smaller dihedral angles generate catalysts that react with higher enantioselectivity than related ligands with larger dihedral angles. In addition, faster rates for reactions of aryl triflates versus those for reactions of aryl bromides allow the alpha-arylations of aryl triflates to be conducted at lower temperatures, and this lower temperature improves enantioselectivity. Finally, studies that compare the enantioselectivities of catalytic reactions to those of stoichiometric reactions of isolated [(segphos)Pd(Ar)(Br)], [(segphos)Pd(Ar)(I)], and [(segphos)Ni(C6H4-4-CN)Br] suggest that catalyst decomposition affects enantioselectivity. PMID:18076166

Liao, Xuebin; Weng, Zhiqiang; Hartwig, John F

2008-01-01

178

Aryl carbinols as nerve agent probes. Influence of the conjugation on the sensing properties  

OpenAIRE

Two new aryl carbinols (1 and 3) have been synthesised and characterised and their ability as OFF-ON probes for the chromogenic detection of the nerve agent simulant in acetonitrile has been tested. In addition compound 2 has been also studied. The carbinols suffered a phosphorylation reaction followed by an elimination process giving rise to the corresponding carbocations. This transformation of the carbinol into the carbocation is responsible for a significant color change. The Royal Soc...

Royo Calvo, Santiago; Gotor Candel, Raul Jesu?s; Costero Nieto, Ana Maria; Parra Alvarez, Margarita; Gil Grau, Salvador; Marti?nez Man?ez, Ramo?n; Sanceno?n Galarza, Fe?lix

2012-01-01

179

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

180

One-step double reduction of aryl nitro and carbonyl groups using hydrazine  

OpenAIRE

Single-step reduction of aryl nitro and carbonyl groups to the corresponding synthetically useful alkyl-anilines occurs with excellent yields by treatment with hydrazine and a base in a solvent-free reaction. The method has been applied to a broad range of compounds with different properties. Investigations into the mechanism of the reduction reveal that each group is reduced independently. A mechanism is proposed for this novel reduction of aromatic nitro groups.

Kelly, Brendan; Diez Cecilia, Elena; Rozas, Isabel

2011-01-01

181

Highly substituted 2,3,7,8,12,13,17,18-octaethylporphyrins with meso aryl residues  

OpenAIRE

Highly substituted porphyrin-bearing meso aryl groups are useful compounds for optical applications and for studies on the interrelationship between the substituent pattern, macrocycle conformation and physical properties. They serve as biomimetic models for the function of tetrapyrroles in nature and help to elucidate modulation of cofactor properties through conformational effects. Using a sequence of lithium organic substitution reactions the synthesis of novel free base 5,10-A2- and 5,10-...

Senge, Mathias

2010-01-01

182

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

183

Catalytic asymmetric synthesis of sterically hindered tertiary ?-aryl ketones.  

Science.gov (United States)

The catalytic asymmetric synthesis of a series of tertiary ?-aryl cyclopentanones and cyclohexanones has been accomplished via a Pd-catalyzed decarboxylative protonation of the corresponding ?-aryl-?-keto allyl esters. Enantioselectivities of up to 92% ee and 74% ee were achieved for cyclopentanone and cyclohexanone substrates, respectively. The route described gives access to these important structural motifs in moderate to high levels of enantioselectivity. In particular, this is only the second direct approach for the preparation of tertiary ?-aryl cyclopentanones. The synthetic approach allows for simple modification of the aryl group. Significantly, substrates containing sterically hindered aryl groups gave the highest levels of enantioselectivity, and these aryl groups were readily installed by a Pb-mediated arylation of a ?-keto allyl ester. PMID:25233274

Doran, Robert; Guiry, Patrick J

2014-10-01

184

Aryl Polyphosphonates: Useful Halogen-Free Flame Retardants for Polymers  

Directory of Open Access Journals (Sweden)

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

185

Electrochemical and Physical properties of N-substituted arylmethylene pyrrole polymers and N-alkylmethine pyrrole copolymers  

International Nuclear Information System (INIS)

Highlights: N-Arylmethylene and methine pyrroles were electropolymerised into polymers and copolymers. N-arylmethylene pyrrole monomers readily formed stable homopyrrole polymer films. N-alkylmethine pyrrole monomers only formed stable copolymers films with pyrrole. N-(1,2-dicarboxyethyl)-1H-pyrrole films readily complexed Cu+ or Cd2+ ions under a appliedve field. -- Abstract: The electrochemical behaviour of N-arylmethylene and N-alkylmethine pyrrole monomers were investigated in their ability to be electropolymerised into polymer and co-polymer films with pyrrole using the techniques of cyclic voltammetry and scanning electron microscopy (SEM). N-substituted arylmethylene pyrrole monomers readily formed homopolymers by the oxidative electropolymerisation of pyrrole monomers by potentiostatic cycling in acetonitrile containing tetrabutylammonium perchlorate. The polymer films formed were brown in appearance and redox active, with the exception of the 1-((4-chlorophenyl)methyl)-1H-pyrrole (1d) which formed a pale yellow film lacking redox activity. The thickness of films produced calculated on the charge consumed followed the order 1e + and Cd2+ ions at a concentration of 1 10?4 M under an appliedve field and to release the metal ion on stepping the potential to zero

186

N-substituted monodentate alcohols as ligands modifying structure, properties and thermal stability of Mo(IV) complexes  

Science.gov (United States)

The reaction of N-substituted alcohols (2-aminoethanol, 3-amino-1-propanol and 2-hydroxyethylhydrazine) with K3Na[Mo(CN)4O2]?6H2O in water-ethanol solution results in isolation of three new complexes of formulae: (PPh4)2[Mo(CN)4O(amet)]?3H2O (1), (amet = 2-aminoethanol), (PPh4)2[Mo(CN)4O(ampro)]?3H2O (2) (ampro = 3-amino-1-propanol) and (PPh4)2[Mo(CN)4O(ethyd)]?3H2O (3) (ethyd = 2-hydroxyethylhydrazine). The isolated salts were characterized by elemental analysis, single crystal X-ray structure measurements, IR and UV-Vis spectroscopy and cyclic voltammetry. The complexes crystalize in triclinic space group with distorted octahedral geometry of the anion. The obtained salts belongs to a very rare group of complexes with monodentate terminal N-donating alcohols. The thermal stability is described for all complexes and compared with crystal structure parameters.

Jurowska, Anna; Szklarzewicz, Janusz; Hodorowicz, Maciej; Tomecka, Monika; Lipkowski, Janusz; Nitek, Wojciech

2015-02-01

187

Catalytic conversion of aryl triazenes into aryl sulfonamides using sulfur dioxide as the sulfonyl source.  

Science.gov (United States)

Various sulfonamides have been synthesized from triazenes and sulfur dioxide. In the presence of just a catalytic amount of BF3OEt2, a series of 1-aryl-triazenes were converted into sulfonyl hydrazines in good to excellent yields. When using CuCl2 as the catalyst, the corresponding sulfonamides can be produced from the 1-aryl triazenes in good yields. PMID:25010993

Li, Wanfang; Beller, Matthias; Wu, Xiao-Feng

2014-08-28

188

Diastereomeric aziridine carbinol catalyzed enantioselective arylation reaction: toward the asymmetric synthesis of both enantiomers of chiral 3-aryl phthalide.  

Science.gov (United States)

The diastereomeric aziridine carbinols are applied, respectively, as efficient chiral ligand in the catalysis of asymmetric arylation and sequential arylation-lactonization cascade. The two diastereomers, which are facilely synthesized from the same chiral source, function as pseudo enantiomers in arylation of aromatic aldehydes providing the different enantiomers of the diarylmethanols with almost the same excellent enantioselectivities. The arylation method is also carried out in tandem with lactonization process to afford a concise synthetic approach to both enantiomers of optically active 3-aryl phthalide. PMID:24912109

Song, Xixi; Hua, Yuan-Zhao; Shi, Jing-Guo; Sun, Ping-Ping; Wang, Min-Can; Chang, Junbiao

2014-07-01

189

Palladium-catalyzed regioselective arylation of an electron-rich olefin by aryl halides in ionic liquids.  

Science.gov (United States)

[figure: see text] Palladium-catalyzed arylation of the electron-rich olefin butyl vinyl ether has been accomplished in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), using as the arylating agents aryl iodides and bromides instead of the commonly used, but commercially unavailable and expensive, aryl triflates. The reaction proceeds with high efficiency and remarkable regioselectivity, leading almost exclusively to substitution by various aryl groups at the olefinic carbon alpha to the heteroatom of butyl vinyl ether. PMID:11430058

Xu, L; Chen, W; Ross, J; Xiao, J

2001-01-25

190

Radiolabeled n-substituted-6-iodo-3, 14-dihydroxy-4, 5alpha-epoxymorphinans, intermediates for producing the same, and a process for the preparation and methods of detecting opioid receptors  

Energy Technology Data Exchange (ETDEWEB)

The invention is directed to radiolabeled N-substituted-6-iodo-3,14-dihydroxy-4,5 alpha-epoxymorphinans, intermediates for producing the same, and a process for the preparation and methods of detecting opioid receptors, wherein Iodo is selected from the group consisting of (123)I and (125)I; and where the N substitution is alkyl, cycloalkylloweralkyl or allyl.

de Costa, B.R.; Iadarola, M.J.; Rothman, R.B.; Berman, K.F.; Rice, K.C.

1991-01-01

191

Palladium-catalyzed arylation of cyanamides.  

Science.gov (United States)

The cross-coupling of alkyl cyanamides with a number of aryl, heteroaryl, and vinyl halide and pseudohalide coupling partners has been developed via a modification of Pd-catalyzed amidation methods. The reactions proceed selectively under mild conditions with reasonable reaction times in moderate to excellent yields. PMID:22142553

Stolley, Ryan M; Guo, Wenxing; Louie, Janis

2012-01-01

192

Palladium(0)-catalyzed arylative dearomatization of phenols.  

OpenAIRE

The palladium-catalyzed arylative dearomatization of phenols to yield spirocyclohexadienone products in good to excellent yields has been developed. Preliminary results demonstrate that the formation of the spirocyclic all-carbon quaternary center can be accomplished with high levels of enantiocontrol (up to 91% ee).

Rousseaux, S.; Garci?a-fortanet, J.; Del Aguila Sanchez, Ma; Buchwald, Sl

2011-01-01

193

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

Energy Technology Data Exchange (ETDEWEB)

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{sup +}-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.

Nakamura, Tomofumi [Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Fukuoka Institute of Health and Environmental Sciences, 39 Mukaizano, Dazaifu-shi, Fukuoka 818-0135 (Japan); Ichinose, Hirofumi [Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Wariishi, Hiroyuki, E-mail: hirowari@agr.kyushu-u.ac.jp [Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Bio-Architecture Center, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Innovation Center for Medical Redox Navigation, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)

2010-04-09

194

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.

195

Mechanism-based common reactivity pattern (COREPA) modelling of aryl hydrocarbon receptor binding affinity.  

Science.gov (United States)

The aryl hydrocarbon receptor is a ligand-activated transcription factor responsive to both natural and synthetic environmental compounds, with the most potent agonist being 2,3,7,8-tetrachlotrodibenzo-p-dioxin. The aim of this work was to develop a categorical COmmon REactivity PAttern (COREPA)-based structure-activity relationship model for predicting aryl hydrocarbon receptor ligands within different binding ranges. The COREPA analysis suggested two different binding mechanisms called dioxin- and biphenyl-like, respectively. The dioxin-like model predicts a mechanism that requires a favourable interaction with a receptor nucleophilic site in the central part of the ligand and with electrophilic sites at both sides of the principal molecular axis, whereas the biphenyl-like model predicted a stacking-type interaction with the aryl hydrocarbon receptor allowing electron charge transfer from the receptor to the ligand. The current model was also adjusted to predict agonistic/antagonistic properties of chemicals. The mechanism of antagonistic properties was related to the possibility that these chemicals have a localized negative charge at the molecule's axis and ultimately bind with the receptor surface through the electron-donating properties of electron-rich groups. The categorization of chemicals as agonists/antagonists was found to correlate with their gene expression. The highest increase in gene expression was elicited by strong agonists, followed by weak agonists producing lower increases in gene expression, whereas all antagonists (and non-aryl hydrocarbon receptor binders) were found to have no effect on gene expression. However, this relationship was found to be quantitative for the chemicals populating the areas with extreme gene expression values only, leaving a wide fuzzy area where the quantitative relationship was unclear. The total concordance of the derived aryl hydrocarbon receptor binding categorical structure-activity relationship model was 82% whereas the Pearson's coefficient was 0.88. PMID:20373220

Petkov, P I; Rowlands, J C; Budinsky, R; Zhao, B; Denison, M S; Mekenyan, O

2010-01-01

196

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

Directory of Open Access Journals (Sweden)

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

197

PCB 126 and Other Dioxin-Like PCBs Specifically Suppress Hepatic PEPCK Expression via the Aryl Hydrocarbon Receptor  

OpenAIRE

Dioxins and dioxin-like compounds encompass a group of structurally related heterocyclic compounds that bind to and activate the aryl hydrocarbon receptor (AhR). The prototypical dioxin is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a highly toxic industrial byproduct that incites numerous adverse physiological effects. Global commercial production of the structurally similar polychlorinated biphenyls (PCBs), however, commenced early in the 20th century and continued for decades; dioxin-like ...

Zhang, Wenshuo; Sargis, Robert M.; Volden, Paul A.; Carmean, Christopher M.; Sun, Xiao J.; Brady, Matthew J.

2012-01-01

198

Pd-Catalyzed Synthesis of ArSCF3 Compounds Under Mild Conditions**  

OpenAIRE

Good to excellent yields of aryl trifluoromethyl sulfides, which are an important class of compounds in both the pharmaceutical and agrochemical areas, can be achieved under mild conditions by the Pd-catalyzed reaction of aryl bromides with a trifluoromethylthiolate nucleophile (see scheme).

Teverovskiy, Georgiy; Surry, David S.; Buchwald, Stephen L.

2011-01-01

199

Biological activity of 1-aryl-3-phenethylamino-1-propanone hydrochlorides and 3-aroyl-4-aryl-1-phenethyl-4-piperidinols on PC-3 cells and DNA topoisomerase I enzyme.  

Science.gov (United States)

A number of studies reported Mannich bases to manifest antimicrobial, cytotoxic, anticancer, anti-inflammatory, and anticonvulsant activities. A considerable number of therapeutically important cytotoxic compounds are active on DNA topoisomerases that regulate the DNA topology. In the present study we evaluated the biological activity of mono-Mannich bases, 1-aryl-3-phenethylamino-1-propanone hydrochlorides (1a-10a), and semicyclic mono-Mannich bases, 3-aroyl-4-aryl-1-phenethyl-4-piperidinols (1b-9b), synthesized in our laboratory. We employed androgen-independent human prostate cancer cells (PC-3) to assess the cytotoxicity of the compounds and extended the biological activity evaluation to cover supercoil relaxation assays of mammalian type I topoisomerases. Our results showed that the compounds had cytotoxicity within the 8.2-32.1 microM range, while two compounds gave rise to a comparable average value in topo I interference of 42% and 40% for 10a (with a hydroxy substituent on the phenyl ring from mono-Mannich bases) and 5b (with a fluoro substituent on the phenyl ring from the semicyclic mono-Mannich base series, piperidinols), respectively. PMID:21319705

Mete, Ebru; Gul, Halise Inci; Canturk, Pakize; Topcu, Zeki; Pandit, Bulbul; Gul, Mustafa; Li, Pui-Kai

2010-01-01

200

Unmasked acyl anion equivalent from acid chloride with indium: reversed-polarity synthesis of unsymmetric aryl aryl and alkenyl aryl ketone through palladium-catalyzed cross-coupling reaction.  

Science.gov (United States)

A reversed-polarity synthetic method of a range of unsymmetric aryl aryl and alkenyl aryl ketones has been developed through Pd-catalyzed cross-coupling reaction of acylindium reagents generated in situ from easily available acid chlorides and indium with various electrophiles such as aryl iodide and triflate and alkenyl triflate. PMID:24506302

Lee, Dohyung; Ryu, Taekyu; Park, Youngchul; Lee, Phil Ho

2014-02-21

201

Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate  

OpenAIRE

The reaction of methyl ketones 1a-g with dimethylformamide dimethylacetal (DMFDMA) afforded the enaminones 2a-g, which were coupled with diazotized aromatic amines 3a,b to give the corresponding aryl hydrazones 6a-h. Condensation of compounds 6a-h with some aromatic heterocyclic amines afforded iminoarylhydrazones 9a-m. Enaminoazo compounds 12a,b could be obtained from condensation of 6c with secondary amines. The reaction of 6e,h with benzotriazolylacetone yielded 14a,b. Also, the reaction o...

Borik, Rita M.; Al-zaydi, Khadijah M.

2007-01-01

202

Design, Synthesis and Anti-Tobacco Mosaic Virus (TMV Activity of 5-Chloro-N-(4-cyano-1-aryl-1H-pyrazol-5-yl-1-aryl-3-methyl-1H-pyrazole-4-carboxamide Derivatives  

Directory of Open Access Journals (Sweden)

Full Text Available A series of novel pyrazole amide derivatives 3a3p which take TMV PC protein as the target has been designed and synthesized by the reactions of 5-chloro-1-aryl-3-methyl-1H-pyrazole-4-carboxylic acids with 5-amino-1-aryl-1H-pyrazole-4-carbonitriles. All the compounds were characterized by 1H-NMR, mass spectroscopy and elemental analysis. Preliminary bioassays indicated that all the compounds acted against the tobacco mosaic virus (TMV with different in vivo and in vitro modes at 500 ?g/mL and were found to possess promising activity. Especially, compound 3p showed the most potent biological activity against tobacco mosaic virus (TMV compared to ningnanmycin, and a molecular docking study was performed and the binding model revealed that the pyrazole amide moiety was tightly embedded in the binding sites of TMV PC (PDB code: 2OM3.

Jin-Jing Xiao

2015-01-01

203

Design, Synthesis and Anti-Tobacco Mosaic Virus (TMV) Activity of 5-Chloro-N-(4-cyano-1-aryl-1H-pyrazol-5-yl)-1-aryl-3-methyl-1H-pyrazole-4-carboxamide Derivatives.  

Science.gov (United States)

A series of novel pyrazole amide derivatives 3a-3p which take TMV PC protein as the target has been designed and synthesized by the reactions of 5-chloro-1-aryl-3-methyl-1H-pyrazole-4-carboxylic acids with 5-amino-1-aryl-1H-pyrazole-4-carbonitriles. All the compounds were characterized by 1H-NMR, mass spectroscopy and elemental analysis. Preliminary bioassays indicated that all the compounds acted against the tobacco mosaic virus (TMV) with different in vivo and in vitro modes at 500 ?g/mL and were found to possess promising activity. Especially, compound 3p showed the most potent biological activity against tobacco mosaic virus (TMV) compared to ningnanmycin, and a molecular docking study was performed and the binding model revealed that the pyrazole amide moiety was tightly embedded in the binding sites of TMV PC (PDB code: 2OM3). PMID:25574822

Xiao, Jin-Jing; Liao, Min; Chu, Ming-Jie; Ren, Zi-Li; Zhang, Xin; Lv, Xian-Hai; Cao, Hai-Qun

2014-01-01

204

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

205

The Novel N-Substituted Benztropine Analog GA2-50 Possesses Pharmacokinetic and Pharmacodynamic Profiles Favorable for a Candidate Substitute Medication for Cocaine Abuse  

OpenAIRE

GA2-50 is a novel N-substituted benztropine analog with improved potency and selectivity for the dopamine transporter. The pharmacokinetic and pharmacodynamic properties of GA2-50 were characterized as a part of its preclinical evaluation as a substitute medication for cocaine abuse. In vitro transport and metabolism studies as well as pharmacokinetic studies in rats were conducted. Effect of GA2-50 on the extracelluar nucleus accumbens (NAc) dopamine levels and on cocaines induced dopamin...

Othman, Ahmed A.; Newman, Amy H.; Eddington, Natalie D.

2008-01-01

206

40 CFR 721.6220 - Aryl sulfonate of a fatty acid mixture, polyamine condensate.  

Science.gov (United States)

...2010-07-01 false Aryl sulfonate of a fatty acid mixture, polyamine condensate...721.6220 Aryl sulfonate of a fatty acid mixture, polyamine condensate...generically as an aryl sulfonate of a fatty acid mixture, polyamine...

2010-07-01

207

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

Directory of Open Access Journals (Sweden)

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.

Hui Xu

2007-04-01

208

Palladium-Catalyzed alpha-Arylation of Tetramic Acids  

DEFF Research Database (Denmark)

A mild, racemization-free, palladium-Catalyzed alpha-arylation of tetramic acids (2,4-pyrrolidinediones) has been developed. Various amino acid-derived tetramic acids were cleanly arylated by treatment with 2 mol % of Pd(OAc)(2), 4 mol % of a sterically demanding biaryl phosphine, 2.3 equiv of K2CO3 or K3PO4, and aryl chlorides, bromides, or triflates in THF. With conventional heating, conversions >95% could be attained after 1 h at 80 degrees C, whereas microwave-induced heating led to much shorter reaction times (5 min at 110 degrees C). The electron density of the aryl electrophile had no effect on their reactivity: both electron-rich and electron-poor aryl chlorides and bromides or triflates led to good yields. Ortho-substituted aryl halides and heteroaryl halides, however, did not undergo the title reaction.

Storgaard, Morten; Dorwald, F. Z.

2009-01-01

209

Palladium-catalyzed direct arylation of polysubstituted benzofurans.  

Science.gov (United States)

An efficient access to 2-substituted 3-arylbenzofurans through a palladium-catalyzed C3 direct arylation of 2-substituted benzofurans with aryl bromides is described. The scope and limitation of this reaction was studied. The method tolerates a variety of functional groups on the aryl halide and has been successfully extended to polysubstituted benzofurans to obtain the corresponding 3-arylbenzofurans with good to excellent yields. PMID:22141919

Carrr, Amandine; Brinet, Dimitri; Florent, Jean-Claude; Rousselle, Patricia; Bertounesque, Emmanuel

2012-02-01

210

Palladium-catalyzed alpha-arylation of oxindoles.  

OpenAIRE

A catalyst generated from Pd(dba)2 and the bulky electron-rich phosphine ligand 2-(dicyclohexylphosphino)-2',4', 6'-tri-i-propyl-1-1'-biphenyl is effective for the alpha-arylation of oxindoles. Generation of the potassium-enolates of a range of oxindoles allows coupling with aryl chlorides, bromides, and triflates. Significant variation of the substitution pattern on both the oxindole and aryl halide is possible.

Durbin, Mj; Willis, Mc

2008-01-01

211

Silver-Mediated Fluorination of Functionalized Aryl Stannanes  

OpenAIRE

We report a regiospecific silver-mediated fluorination of aryl stannanes. The presented reaction can afford complex fluoroarenes from readily available phenols in three steps. The operational simplicity and the broad substrate scope of the fluorination should render this reaction a useful tool for the synthesis of milligram to gram quantities of functionalized aryl fluorides. Silver-mediated oxidative transformations of aryl nucleophiles that proceed via bimetallic redox processes are a new a...

Ritter, Tobias; Furuya, Takeru; Strom, Alexandra E.

2009-01-01

212

Poly (Aryl Ether Ketones) Bearing Alkylated Side Chains  

Science.gov (United States)

This invention relates generally to poly(aryl ether ketones) bearing alkylated side chains. It relates particularly to soluble, thermally stable. low dielectric poly(aryl ether ketones) with alkylated side chains and especially to films and coatings thereof. These poly(aryl ether ketones) have a structural formula wherein Y is selected from the group consisting of CF3 and CH3; and wherein R is C(sub n)H(sub (2n+1)) and n = 11-18.

Cassidy, Patrick E. (Inventor); Fitch, John W., III (Inventor); Gronewald, Scott D. (Inventor); St.Clair, Ann K. (Inventor); Stoakley, Diane M. (Inventor)

2002-01-01

213

Catalytic SNAr of unactivated aryl chlorides.  

Science.gov (United States)

We present nucleophilic aromatic substitution of unsubstituted aryl chlorides via a mechanism that is catalytic in [CpRu(p-cymene)]PF6 and involves a Ru(?(6)-arylchloride) intermediate. From the spectroscopic evidence we infer that arene exchange is the rate limiting step in this process and develop several new Ru(ii) complexes that lower the activation barrier to arene exchange. PMID:25300517

Walton, James W; Williams, Jonathan M J

2015-02-01

214

Photooxidation of mixed aryl and biarylphosphines.  

Science.gov (United States)

Arylphosphines and dialkylbiarylphosphines react with singlet oxygen to form phosphine oxides and phosphinate esters. For mixed arylphosphines, the most electron-rich aryl group migrates to form the phosphinate, while for dialkylbiarylphosphines migration of the alkyl group occurs. Dialkylbiarylphosphines also yield arene epoxides, especially in electron-rich systems. Phosphinate ester formation is increased at high temperature, while protic solvents increase the yield of epoxide. The product distribution provides evidence for Buchwald's recent conformational model for the aerobic oxidation of dialkylbiarylphosphines. PMID:20527907

Zhang, Dong; Celaje, Jeff A; Agua, Alon; Doan, Chad; Stewart, Timothy; Bau, Robert; Selke, Matthias

2010-07-01

215

Syntheses and Pharmacological Evaluations of Novel N-substituted Bicyclo-heptan-2-amines at NMDA Receptors  

OpenAIRE

Several novel norcamphor (bicycloheptane) based compounds were designed and synthesized as noncompetitive NMDA receptor antagonists at the Phencyclidine (PCP) binding sites. The heterocyclic ring was also varied to examine piperidine, pyrrolidine and morpholine groups. We examined pharmacological activities of these compounds in vitro (binding studies) and in vivo (MES test). Pharmacological evaluations revealed one of the compounds, 5a, to be a good lead, exhibiting moderate binding at NMDA ...

Ates-alagoz, Zeynep; Sun, Shengguo; Wallach, Jason; Adejare, Adeboye

2011-01-01

216

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

Directory of Open Access Journals (Sweden)

Full Text Available 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

2013-02-01

217

Total Synthesis of Hibispeptin A via Pd-Catalyzed C(sp(3))-H Arylation with Sterically Hindered Aryl Iodides.  

Science.gov (United States)

To access the key Ile-Hpa pseudodipeptide motif in hibispeptins, a series of bidentate carboxamide-based auxiliary groups have been explored to facilitate the palladium-catalyzed arylation of unactivated ?-C(sp(3))-H bonds of Ile precursor with aryl iodides. A new pyridylmethylamine-based auxiliary group PR is introduced, which permits the use of more sterically hindered ortho-substituted aryl iodide substrates and can be removed under mild conditions. Pd-catalyzed PR-directed ?-C(sp(3))-H arylation enabled the first total synthesis of hibispeptin A. PMID:25487778

He, Gang; Zhang, Shu-Yu; Nack, William A; Pearson, Ryan; Rabb-Lynch, Javon; Chen, Gong

2014-12-19

218

Evidence for In Situ Catalyst Modification During the Pd-Catalyzed Conversion of Aryl Triflates to Aryl Fluorides  

OpenAIRE

A mechanistic investigation of the Pd-catalyzed conversion of aryl triflates to fluorides is presented. Studies reveal that CF reductive elimination from a LPd[superscript II](aryl)F complex (L = t-BuBrettPhos or RockPhos) does not occur when the aryl group is electron rich. Evidence is presented that a modified phosphine, generated in situ, serves as the actual supporting ligand during catalysis with such substrates. A preliminary study of the reactivity of a LPd[superscript II](aryl)F co...

Maimone, Thomas J.; Milner, Phillip J.; Kinzel, Tom; Zhang, Yong; Takase, Michael K.; Buchwald, Stephen L.

2011-01-01

219

Synthesis, Half-Wave Potentials and Antiproliferative Activity of 1-Aryl-substituted Aminoisoquinolinequinones  

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Full Text Available The synthesis of a variety of 1-aryl-7-phenylaminoisoquinolinequinones from 1,4-benzoquinone and arylaldehydes via the respective 1-arylisoquinolinequinones is reported. The cyclic voltammograms of the new compounds exhibit two one-electron reduction waves to the corresponding radical-anion and dianion and two quasi-reversible oxidation peaks. The half-wave potential values (EI of the members of the series have proven sensitive to the electron-donor effect of the aryl group (phenyl, 2-thienyl, 2-furyl at the 1-position as well as to the phenylamino groups (anilino, p-anisidino at the 7-position. The antiproliferative activity of the new compounds was evaluated in vitro using the MTT colorimetric method against one normal cell line (MRC-5 lung fibroblasts and two human cancer cell lines: AGS human gastric adenocarcinoma and HL-60 human promyelocytic leukemia cells in 72-h drug exposure assays. Among the series, compounds 5a, 5b, 5g, 5h, 6a and 6d exhibited interesting antiproliferative activities against human gastric adenocarcinoma. The 1-arylisoquinolinequinone 6a was found to be the most promising active compound against the tested cancer cell lines in terms of IC50 values (1.19; 1.24 M and selectivity index (IS: 3.08; 2.96, respect to the anti-cancer agent etoposide used as reference (IS: 0.57; 0.14.

Juana Andrea Ibacache

2014-01-01

220

Synthesis and biological evaluation of some new N4-aryl substituted 5-chloroisatin-3-thiosemicarbazones.  

Science.gov (United States)

A new series of sixteen N4-aryl substituted 5-chloroisatin-3-thiosemicarbazones 2a-2p has been synthesized, characterized and tested for selected biological activities i.e. cytotoxicity, phytotoxicity and urease inhibition. In the brine shrimp bioassay, all the synthesized compounds gave LD50 values>2.30x10(-4) M-2.79x10(-4) M and were, therefore, found to be almost inactive, whereas in phytotoxicity assay, regardless of the nature of aryl substituents, they displayed weak to moderate (5-40%) phytotoxic activity at the highest tested concentrations (500 or 1000 ?g/mL). In urease inhibition bioassay, compounds 2a, 2c, 2e, 2f, 2k and 2m exhibited relatively a higher degree of urease inhibition with IC50 values ranging from 38.91 ?M to 76.65 ?M and thus proved to be potent inhibitors of the enzyme. Of these, 2f and 2m displayed pronounced inhibition with IC50 values 38.91 ?M and 39.50 ?M, respectively, and may act as lead compounds for further studies. Structure-activity relationship (SAR) studies revealed that electronic effects of the substituents about the phenyl ring at N4 of the thiosemicarbazone moiety played an important role in enhancing the urease inhibitory potential of some of the synthesized compounds. PMID:22530899

Pervez, Humayun; Ramzan, Muhammad; Yaqub, Muhammad; Nasim, Faiz-ul-Hassan; Khan, Khalid Mohammed

2012-05-01

221

Facile synthesis and herbicidal evaluation of 2-aryl-4h-3, 1-benzoxazin-4-ones  

International Nuclear Information System (INIS)

The present work deals with the synthesis of 4H-3,1-benzoxazin-4-ones carrying an aryl functional group at position-2. Synthesized compounds tested for herbicidal activity at three different doses (500 micro g/mL, 50 micro g/mL and 5 micro g/mL). Most of the compounds exhibited significant herbicidal activity against Lemna aequinocitalis welv at higher dose (500 micro g/mL). Among the tested compounds 2-phenyl-4H-3,1-benzoxazin-4-one (3a) and 2-(3-chlorophenyl)-4H-3,1-benzoxazin-4-one (3l) completely inhibited the plant growth at 500 and 50 micro g/mL concentrations. All the synthetic compounds were characterized by FT-IR, 1H NMR, EI-MS and elemental analysis. (author)

222

Regioselective Heck reaction of aliphatic olefins and aryl halides.  

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A regioselective Heck reaction of aliphatic olefins and aryl bromides is realized at internal carbons of olefins. Methanol solvent promoted halide ionization from neutral arylpalladium halide complexes via hydrogen bonding, so as to create cationic aryl-Pd species for regioselective olefin insertion. PMID:24060852

Qin, Liena; Hirao, Hajime; Zhou, Jianrong Steve

2013-11-11

223

Rhodium-Catalyzed C-H Bond Arylation of Arenes  

Science.gov (United States)

A review is presented of synthetic methods for the preparation of biaryls by the rhodium-catalyzed C-H bond arylation of arenes with aryl halides (C-H/C-X couplings), arylmetal reagents (C-H/C-M couplings) and arenes (C-H/C-H couplings), with an emphasis on postulated mechanisms and their implications on reactivity, selectivity and substrate scope.

Bouffard, Jean; Itami, Kenichiro

224

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

225

Photodissociation of aryl and aryl-alkyl halides at 193 nm: Fragment translational energy distributions  

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Molecular beams of a number of aryl and aryl-alkyl halide molecules were photodissociated using an excimer laser at 193 nm and fragment translational energy distributions measured. Previous work had shown that dissociation of aryl halide molecules takes place by a spin-orbit dependent crossing from an intermediate (?, ?*) delocalized state to a triplet (?, ?*) state localized on the C-X bond (X=Cl,Br,I). The vibrational energy of the intermediate state remains in the aromatic framework; thus the fragment translational energy distribution reflects only the electronic but not the vibrational energy of the intermediate state. This fact is exploited in identifying the electronic nature of this state. Present work indicates that both phenyl and naphthyl halide molecules dissociate at 193 nm to produce vibrationally hot aryl radicals. The actual dissociation pathway depends on the competition between intersystem crossing and internal conversion which are functions of both ring size and halogen substituents. Iodobenzene dissociates from S3, S2, and S1 whereas chlorobenzene internally converts to S1 entirely before dissociating. Bromobenzene also dissociates from all three singlet states whereas 2-bromonaphthalene dissociates from S1 even though it is excited to S4 at 193 nm. Fluorination (C6F5I and C6F5Br) drastically reduced the kinetic energy of the fragments which seems to indicate dissociation from a highly distorted aryl ring configuration which may be related to the well-known benzene structural isomers. At lower photon energies it had been found that the flux of fragments of aryl iodides was anisotropic with respect to the E vector of the dissociating light but the flux from aryl bromides was isotropic. The same results are found at 193 nm with a somewhat different interpretation. In all cases, C6H5CH2X and C6H5C2H4X produced translational energy distributions peaking at zero energy which implies that intersystem crossing is so slow that the molecule internally converts from S3 to S0 with subsequent statistical unimolecular decomposition.

Freedman, A.; Yang, S. C.; Kawasaki, M.; Bersohn, R.

1980-01-01

226

Palladium-catalyzed amination of aryl sulfides with anilines.  

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A combination of a palladium-NHC catalyst and potassium hexamethyldisilazide enables the amination of aryl sulfides with anilines to afford a wide variety of diarylamines. The reaction conditions are versatile enough for the reaction of even bulky ortho-substituted aryl sulfides. This amination can be applied to the modular synthesis of N-aryl carbazoles from the corresponding ortho-bromothioanisoles. As aryl sulfoxides undergo extended Pummerer reactions to afford ortho-substituted aryl sulfides, the Pummerer products are thus useful substrates for the amination to culminate in efficient syntheses of a 2-anilinobenzothiophene and an indole as proof-of-principle of the utility of the extended Pummerer reaction/amination cascade. PMID:25044919

Sugahara, Tomohiro; Murakami, Kei; Yorimitsu, Hideki; Osuka, Atsuhiro

2014-08-25

227

Synthesis and Antiviral Bioactivities of 2-Aryl- or 2-Methyl-3-(substituted- Benzalamino-4(3H-quinazolinone Derivatives  

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Full Text Available A simple and general method has been developed for the synthesis of various4(3H-quinazolinone derivatives by the treatment of the appropriate 3-amino-2-aryl-4(3H-quinazolinone with a substituted benzaldehyde in ethanol. The structures of the compoundswere characterized by elemental analysis, IR, 1H-NMR and 13C-NMR spectra. The title 2-aryl- or 2-methyl-3-(substituted-benzalamino-4(3H-quinazolinone compounds III-1~III-31 were found to possess moderate to good antiviral activity. Semi-quantitative PCR andReal Time PCR assays were used to ascertain the target of action of compound III-31against TMV. The studies suggest that III-31 possesses antiviral activity due to inductionof up-regulation of PR-1a and PR-5, thereby inhibiting virus proliferation and movementby enhancement of the activity of some defensive enzyme.

Zhuo Chen

2007-12-01

228

Stereocontrolled syntheses of tetralone- and naphthyl-type lignans by a one-pot oxidative [3,3] rearrangement/Friedel-Crafts arylation.  

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The development of a stereoselective one-pot oxidative [3,3]?sigmatropic rearrangement/Friedel-Crafts arylation that provides enantioenriched benzhydryl compounds is reported. The utility of this new transformation is demonstrated by the concise synthesis of several tetralone- and naphthyl-type lignan natural products, many of which display anti-malarial activity. PMID:24356917

Reddel, Jordan C T; Lutz, Kelly E; Diagne, Abdallah B; Thomson, Regan J

2014-01-27

229

C- versus O-Arylation of an Enol-Lactone Using Potassium tert-butoxide  

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Full Text Available Abstract: The use of potassium tert-butoxide as the base in arylation reactions of an enollactone with a series of benzyl halides was explored. Our work demonstrates that the ratio of C-arylation to O-arylation varies with the substitution pattern of the aryl halide.

El Moktar Essassi

2003-05-01

230

Palladium-catalysed carbonylative ?-arylation of acetone and acetophenones to 1,3-diketones.  

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Three COmponent -arylation: A carbonylative ketone -arylation process employing acetone for the first time, as well as acetophenones, is described (see scheme). The reaction tolerates a range of (hetero)aryl iodides and several functionalised aryl ketone coupling partners. Only low pressures of molecular CO are applied and no additional solvent is necessary. PMID:24175338

Schranck, Johannes; Tlili, Anis; Alsabeh, Pamela G; Neumann, Helfried; Stradiotto, Mark; Beller, Matthias

2013-09-16

231

Synthesis and structure-activity relationship of 2-arylamino-4-aryl-pyrimidines as potent PAK1 inhibitors.  

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2-Arylamino-4-aryl-pyrimidines were found to be potent inhibitors of PAK1 kinase. The synthesis and SAR are described. The incorporation of a bromide at the 5-position of the pyrimidine core and in combination with a 1,2-dimethylpiperazine pendant domain yielded a lead compound with potent PAK1 inhibition and anti-proliferative activity in various colon cancer cell lines. PMID:23756368

Xu, Yong; Foulks, Jason M; Clifford, Adrianne; Brenning, Benjamin; Lai, Shuping; Luo, Bai; Parnell, K Mark; Merx, Shannon; McCullar, Michael V; Kanner, Steven B; Ho, Koc-Kan

2013-07-15

232

Synthesis of 5-Dialkyl(aryl)aminomethyl-8-hydroxyquinoline Dansylates as Selective Fluorescent Sensors for Fe3+  

OpenAIRE

A series of 5-dialkyl(aryl)aminomethyl-8-hydroxyquinoline dansylates were synthesized and their fluoroionophoric properties toward representative alkali ions, alkaline earth ions and transition metal ions were investigated. Among the selected ions, Fe3+ caused considerable quenching of the fluorescence, while Cr3+ caused quenching to some extent. The absence of any significant fluorescence quenching effects of the other ions examined, especially Fe2+, renders these compounds highly useful Fe3...

Yaowu Sha; Feng Wang; Ruogu Peng

2007-01-01

233

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

OpenAIRE

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 lo...

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; Bloomquist, Jeffrey R.; Carlier, Paul R.

2012-01-01

234

Structure of 1-aryl-3-alkyl(phenyl)-5-(2-benzthiazolyl) formazanates of zinc(2) and cadmium(2)  

International Nuclear Information System (INIS)

Data of 13C NMR spectra show that 1-aryl-3-alkyl(phenyl)-5-(2-benzthiazolyl) formazanates of zinc(2) and cadmium(2) are characterized by pseudooctahedral structure. The ligand of complex compound is in E1.2Z2.3E3.4-configuration and is coordinated throgh N1 and N4 nitrogen atoms of formazan chain and through N3 atom of benzthiazol

235

Investigation of N-aryl-3-alkylidenepyrrolinones as potential Niemann-Pick type C disease therapeutics1  

OpenAIRE

A five-step synthesis of an array of N-aryl-3-alkylidenepyrrolinones, which are potential Niemann-Pick type C (NPC) disease therapeutics, is described. The synthetic route allows for the production of analogues, including photoaffinity and biotinylated derivatives. Compound 1a increased esterification by acyl-coenzyme A:cholesteryl acyltransferase in NPC1 mutant cells. It also decreased LDL uptake and increased cholesterol efflux in both NPC1-deficient and normal cells.

Cosner, Casey C.; Markiewicz, John T.; Bourbon, Pauline; Mariani, Christopher J.; Wiest, Olaf; Rujoi, Madalina; Rosenbaum, Anton; Huang, Amy; Maxfield, Frederick R.; Helquist, Paul

2009-01-01

236

Nucleophilic aryl fluorination and aryl halide exchange mediated by a Cu(I)/Cu(III) catalytic cycle.  

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Copper-catalyzed halide exchange reactions under very mild reaction conditions are described for the first time using a family of model aryl halide substrates. All combinations of halide exchange (I, Br, Cl, F) are observed using catalytic amounts of Cu(I). Strikingly, quantitative fluorination of aryl-X substrates is also achieved catalytically at room temperature, using common F(-) sources, via the intermediacy of aryl-Cu(III)-X species. Experimental and computational data support a redox Cu(I)/Cu(III) catalytic cycle involving aryl-X oxidative addition at the Cu(I) center, followed by halide exchange and reductive elimination steps. Additionally, defluorination of the aryl-F model system can be also achieved with Cu(I) at room temperature operating under a Cu(I)/Cu(III) redox pair. PMID:22026511

Casitas, Alicia; Canta, Merc; Sol, Miquel; Costas, Miquel; Ribas, Xavi

2011-12-01

237

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

238

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

239

Unexpected features of 127I NQR spectra of dialkyl(aryl)substituted tin(4) iodide adducts  

International Nuclear Information System (INIS)

Compounds of R2SnI2D2-type, where R constitutes alkyl or aryl radicals, D - HMPT, DMSO, Py, are studied through the method of NQR 127I spectroscopy. According to the correlation obtained between the effective charge on the iodine atom and the corresponding interatomic distance Sn-I it is established that elongation of the Sn-I bond by 0.1 A is accompanied by increase in the negative charge on the iodine atom approximately by 0.12 e. 6 refs.; 1 fig

240

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

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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

241

Interaction of fish aryl hydrocarbon receptor paralogs (AHR1 and AHR2) with the retinoblastoma protein  

OpenAIRE

The aryl hydrocarbon receptor (AHR) mediates the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. In some mammalian cell lines, TCDD induces G1 cell cycle arrest, which depends on an interaction between the AHR and the retinoblastoma tumor suppressor (RB). Mammals possess one AHR, whereas fishes possess two or more AHR paralogs that differ in the domains important for AHR-RB interactions in mammals. To test the hypothesis that fish AHR paralogs differ in thei...

Merson, Rebeka R.; Karchner, Sibel I.; Hahn, Mark E.

2009-01-01

242

Design, synthesis and biological evaluation of new aryl thiosemicarbazone as antichagasic candidates.  

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The present work reports on the synthesis, biological assaying and docking studies of a series of 12 aryl thiosemicarbazones, which were planned to act over two main enzymes, cruzain and trypanothione reductase. These enzymes are used as targets of trypanocidal activity in Chagas disease control with a minimal mutagenic profile. Three p-nitroaromatic thiosemicarbazones showed high activity against Trypanosoma cruzi in invitro assays (IC50<57?M), and no mutagenic profile was observed in micronucleous tests. Although the invitro inhibition test showed that 10-?M doses of eight compounds inhibited cruzain activity, no correlation was found between cruzain inhibition and trypanocidal activity. PMID:23851115

Blau, Lorena; Menegon, Renato Farina; Trossini, Gustavo H G; Molino, Joo Vitor Dutra; Vital, Drielli Gomes; Cicarelli, Regina Maria Barretto; Passerini, Gabriela Du; Bosquesi, Priscila Longhin; Chin, Chung Man

2013-09-01

243

N-heterocyclic carbene-palladium(II)-1-methylimidazole complex-catalyzed Suzuki-Miyaura coupling of aryl sulfonates with arylboronic acids.  

Science.gov (United States)

A well-defined NHC-Pd(II)-Im complex 1 was found to be an effective catalyst for the Suzuki-Miyaura coupling of aryl sulfonates including tosylates and phenylsulfonates with arylboronic acids, giving the desired coupling products in good to high yields. Acceptable yields can also be achieved even by using the less reactive mesylates as the substrates. It is worthy of noting here that this is the first example of NHC-Pd(II) complex-catalyzed Suzuki-Miyaura coupling of aryl sulfonates with arylboronic acids, enriching an inexpensive, convenient, and alternative method for the synthesis of biaryl compounds. PMID:22804630

Wang, Zhan-Yong; Chen, Gao-Qi; Shao, Li-Xiong

2012-08-01

244

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

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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

245

Synthesis and in vitro microbiological evaluation of novel 4-aryl-5-isopropoxycarbonyl-6-methyl-3,4-dihydropyrimidinones.  

Science.gov (United States)

Seven 4-aryl-5-isopropoxycarbonyl-6-methyl-3,4-dihydropyrimidin-2(1H)-ones 4a-g and 4-phenyl-5-isopropoxycarbonyl-6-methyl-3,4-dihydropyrimidin-2(1H)-thione 4h have been synthesized by a one-pot cyclocondensation of aldehydes, isopropyl acetoacetate and urea/thiourea in ethanol by using strontium chloride hexahydrate as the catalyst. All the compounds were screened for their antibacterial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella typhi and antifungal activity against Candida albicans, Aspergillus flavus, Rhizopus and Mucor. Compounds 4b, 4c, 4f, 4g exhibited excellent in vitro antibacterial activity against Staphylococcus aureus, Salmonella typhi and Pseudomonas aeruginosa and potent in vitro antifungal activity against Candida albicans, Rhizopus and Mucor. Compound 4f with a nitro group at the para position of the 4-aryl group and 4g with a fluorine at the para position of the 4-aryl group showed more activity than the standard drugs. PMID:19800716

Chitra, S; Devanathan, D; Pandiarajan, K

2010-01-01

246

SYNTHESIS OF 6, 7-DISUBSTITUTED-2-ARYL-4H-1-BENZOPYRAN-4-ONES AS ANTIBACTERIAL AGENTS  

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Full Text Available Benzopyrones constitute one of the major classes of natural products. Both semisynthetic and natural benzopyrone derivatives are known to possess important biological properties and as a result several attempts and procedures have been reported and developed for their synthesis. The present study was designed to synthesize various substituted 2-aryl-4H-1-benzopyran-4-one derivatives. The title compounds were prepared starting from a diketone i.e. 4-substituted-2-hydroxydiaroylmethane. The structures of these newly synthesized compounds were confirmed by their analytical and spectral data. The synthesized compounds were subjected for antibacterial screening against P.aeruginosa, B.subtilis and E.coli. Among all the derivatives 5d showed maximum activity against P.aeruginosa & E.coli and 5b showed highest activity against B.subtilis & E.coli. The results of the antibacterial screening suggest that some of the substituted 2-aryl-4H-1-benzopyran-4-one derivatives possess appreciable antibacterial activity and may prove useful in future drug development.

Som Sukhen

2012-03-01

247

Antioxidant properties of diorganoyl diselenides and ditellurides: modulation by organic aryl or naphthyl moiety.  

Science.gov (United States)

Diorganoyl dichalcogenide compouds can have antioxidant activity in different in vitro and in vivo models. Here, we have compared the potential antioxidant activity of 1-dinaphthyl diselenide (1-NapSe)(2), 2-dinaphthyl diselenide (2-NapSe)(2), 1-dinaphthyl distelluride (1-NapTe)(2), 2-dinaphthyl ditelluride (2-NapTe)(2) with their well-studied analogs diphenyl diselenide ((PhSe)(2)) and diphenyl telluride ((PhTe)(2)). (PhSe)(2), (PhTe)(2), and naphthalene analogs-inhibited Fe(II)-induced lipid peroxidation, catalytically decomposed hydrogen peroxide and oxidized thiols, such as dithiothreitol (DTT), Cysteine (CYS), dimercaptopropionic acid (DMPS), and thiophenol (PhSH). (PhSe)(2) was the less potent of the tested compounds against Fe(II)-induced lipid peroxidation in brain homogenates and the change in the organic moiety from an aryl to naphthyl group increased considerably the antioxidant potency of diselenide compounds. However, the change from aryl to naphthyl had little effect on the thio-peroxidase-like activity of diorganoyl dichalcogenides. These results suggest that minor changes in the organic moiety of aromatic diselenide compounds can modify profoundly their capacity to inhibit iron-induced lipid peroxidation. The pharmacological properties of organochalcogens are thought to be linked to their capacity of modulating oxidative stress. Consequently, it becomes important to explore the toxicological properties of dinaphthyl diselenides and ditellurides. PMID:22983825

Ibrahim, Mohammad; Hassan, Waseem; Meinerz, Daiane Francine; Dos Santos, Matheus; V Klimaczewski, Claudia; M Deobald, Anna; Costa, Maricilia S; Nogueira, Cristina W; Barbosa, Nilda B V; Rocha, Joao B T

2012-12-01

248

Cloning, expression and characterization of an aryl-alcohol dehydrogenase from the white-rot fungus Phanerochaete chrysosporium strain BKM-F-1767  

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Full Text Available Abstract Background The white-rot fungus Phanerochaete chrysosporium is among the small group of fungi that can degrade lignin to carbon dioxide while leaving the crystalline cellulose untouched. The efficient lignin oxidation system of this fungus requires cyclic redox reactions involving the reduction of aryl-aldehydes to the corresponding alcohols by aryl-alcohol dehydrogenase. However, the biochemical properties of this enzyme have not been extensively studied. These are of most interest for the design of metabolic engineering/synthetic biology strategies in the field of biotechnological applications of this enzyme. Results We report here the cloning of an aryl-alcohol dehydrogenase cDNA from the white-rot fungus Phanerochaete chrysosporium, its expression in Escherichia coli and the biochemical characterization of the encoded GST and His6 tagged protein. The purified recombinant enzyme showed optimal activity at 37C and at pH 6.4 for the reduction of aryl- and linear aldehydes with NADPH as coenzyme. NADH could also be the electron donor, while having a higher Km (220 ?M compared to that of NADPH (39 ?M. The purified recombinant enzyme was found to be active in the reduction of more than 20 different aryl- and linear aldehydes showing highest specificity for mono- and dimethoxylated Benzaldehyde at positions 3, 4, 3,4 and 3,5. The enzyme was also capable of oxidizing aryl-alcohols with NADP?+?at 30C and an optimum pH of 10.3 but with 15 to 100-fold lower catalytic efficiency than for the reduction reaction. Conclusions In this work, we have characterized the biochemical properties of an aryl-alcohol dehydrogenase from the white-rot fungus Phanerochaete chrysosporium. We show that this enzyme functions in the reductive sense under physiological conditions and that it displays relatively large substrate specificity with highest activity towards the natural compound Veratraldehyde.

Yang Dong-Dong

2012-06-01

249

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

Science.gov (United States)

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

250

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

251

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

Science.gov (United States)

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

252

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

253

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

Energy Technology Data Exchange (ETDEWEB)

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

254

Mild copper-TBAF-catalyzed N-arylation of sulfoximines with aryl siloxanes.  

Science.gov (United States)

An efficient copper-TBAF-catalyzed C-N bond formation of sulfoximines with arylsiloxanes in dichloromethane at room temperature, affording the desired N-aryl sulfoximines in good to excellent yields under an oxygen atmosphere, is reported. This method complements the existing synthetic approaches due to some advantageous properties of arylsiloxanes such as availability, low toxicity, ease of handling, high stability, and environmental benignity under mild reaction conditions, thus opening a new approach to practical C-N bond formation. PMID:25142135

Kim, Jaeeun; Ok, Jinpyo; Kim, Sanghyuck; Choi, Wonseok; Lee, Phil Ho

2014-09-01

255

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

256

Copper/N,N-Dimethylglycine Catalyzed Goldberg Reactions Between Aryl Bromides and Amides, Aryl Iodides and Secondary Acyclic Amides  

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Full Text Available An efficient and general copper-catalyzed Goldberg reaction at 90110 C between aryl bromides and amides providing the desired products in good to excellent yields has been developed using N,N-dimethylglycine as the ligand. The reaction is tolerant toward a wide range of amides and a variety of functional group substituted aryl bromides. In addition, hindered, unreactive aromatic and aliphatic secondary acyclic amides, known to be poor nucleophiles, are efficiently coupled with aryl iodides through this simple and cheap copper/N,N-dimethylglycine catalytic system.

Liqin Jiang

2014-08-01

257

Accessing 2,1-borazaronaphthols: self-arylation of 1-alkyl-2-aryl-3-bromo-2,1-borazaronaphthalenes.  

Science.gov (United States)

Unlike their B-alkyl counterparts, brominated N-alkyl B-aryl 2,1-borazaronaphthalenes undergo a self-arylation reaction in the presence of a catalytic amount of palladium and base, in which the azaborine serves as both the electrophile and the nucleophile. The products of the self-arylation are air- and moisture-stable 2,1-borazaronaphthols, previously only observed in basic alcoholic solvents. The steric encumbrance of the azaborine appears to prevent formation of the corresponding boron acid anhydride, allowing access to a family of 2,1-borazaronaphthol derivatives. PMID:25133658

Molander, Gary A; Wisniewski, Steven R

2014-09-01

258

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

259

Advances in the synthesis of 4-aryl- and 4-hetarylpyridines  

Energy Technology Data Exchange (ETDEWEB)

Information on the methods of synthesis of 4-aryl- or 4-hetaryl-substituted pyridines developed in the recent years is discussed and generalised. Examples of the practical use of 4-(het)arylpyridine derivatives are given.

Gromov, Sergei P; Fomina, Marina V [Photochemistry Centre, Russian Academy of Sciences, Moscow (Russian Federation)

2008-12-31

260

Fluorine-containing alkyl(aryl) vinyl sulfides  

Energy Technology Data Exchange (ETDEWEB)

Approaches to the synthesis of fluorine-containing alkyl(aryl) vinyl sulfides, their reactions with electrophilic and nucleophilic reagents and the behaviour in cycloaddition and oxidation reactions are considered systematically.

Sizov, Aleksei Yu; Kovregin, Aleksei N; Ermolov, Aleksandr F [Military University of Radiational, Chemical and Biological Defence (Russian Federation)

2003-04-30

261

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

262

Novel 2-amino-isoflavones exhibit aryl hydrocarbon receptor agonist or antagonist activity in a species/cell-specific context  

OpenAIRE

The Aryl hydrocarbon receptor (AhR) mediates the induction of a variety of xenobiotic metabolism genes. Activation of the AhR occurs through binding to a group of structurally diverse compounds, most notably dioxins, which are exogenous ligands. Isoflavones are part of a family which include some well characterised endogenous AhR ligands. This paper analysed a novel family of these compounds, based on the structure of 2-amino-isoflavone. Initially two luciferase-based cell models, mouse H1L6....

Wall, Richard J.; He, Guochun; Denison, Michael S.; Congiu, Cenzo; Onnis, Valentina; Fernandes, Alwyn; Bell, David R.; Rose, Martin; Rowlands, J. Craig; Balboni, Gianfranco; Mellor, Ian R.

2012-01-01

263

Synthesis of new N-substituted 5-arylidene-2,4-thiazolidinediones as anti-inflammatory and antimicrobial agents.  

Science.gov (United States)

A novel series of 5-arylidene-2,4-thiazolidinediones (TZDs) 2a-p was synthesized from the condensation of 3-((2-phenylthiazol-4-yl)methyl)thiazolidine-2,4-dione with different benzaldehyde derivatives. All the structures were confirmed by their spectral (IR, H NMR, C NMR and mass) and elemental analytical data. The new molecules were evaluated in vivo as anti-inflammatory agents in an acute experimental inflammation, evaluating the acute phase bone marrow response and phagocyte activity. All compounds, excepting one, reduced the absolute leukocytes count due to the lower neutrophil percentage. Phagocytary index was decreased by the same molecules, while only half of them reduced the phagocytary activity. The effect was superior to meloxicam, the reference anti-inflammatory drug, for the majority of the TZD derivatives. The new molecules were also investigated for their antimicrobial properties on Gram-positive and Gram-negative bacteria and one fungal strain. Two compounds (2e and 2n) manifested growth inhibition capacity on all the tested strains. PMID:23666636

Nastas?, Cristina; Tiperciuc, Brndu?a; Prvu, Alina; Duma, Mihaela; Ionu?, Ioana; Oniga, Ovidiu

2013-06-01

264

Reaction of 3-aryl-2-benzoyloxiranes with alkyl thiocyanates  

International Nuclear Information System (INIS)

3-Aryl-2-benzoyloxiranes and alkyl thiocyanates in the presence of an equivalent amount of anhydrous AlCl3 form erythro-N-(2-benzoyl-1-aryl-2-chloroethyl)-S-alkyl thiocarbamates and ?-diketones. p-Tolyl- and p-anisyl-2-benzoyl-oxiranes do not react with alkyl thiocyanates, but isomerize to the respective ?-diketones, and form the threo-chlorohydrins in low yield

265

Palladium catalyzed aryl(alkyl)thiolation of unactivated arenes.  

Science.gov (United States)

A general palladium-catalyzed aryl(alkyl)thiolation of various substituted unactivated arenes is accomplished for the synthesis of diverse unsymmetrical diaryl(alkyl) sulfides in good yield employing electrophilic sulfur reagent 6 derived from succinimide. The developed strategy was coupled with intramolecular arylation of a C-H bond to afford dibenzothiphene derivatives, an important moiety in material science as organic semiconductors. PMID:24437617

Saravanan, Perumal; Anbarasan, Pazhamalai

2014-02-01

266

Discovery of nanomolar ligands for 7-transmembrane G-protein-coupled receptors from a diverse N-(substituted)glycine peptoid library.  

Science.gov (United States)

Screening a diverse, combinatorial library of ca. 5000 synthetic dimer and trimer N-(substituted)glycine "peptides" yielded novel, high-affinity ligands for 7-transmembrane G-protein-coupled receptors. The peptoid library was efficiently assembled using readily available chemical building blocks. The choice of side chains was biased to resemble known ligands to 7-transmembrane G-protein-coupled receptors. All peptides were screened in solution-phase, competitive radioligand-binding assays. Peptoid trimer CHIR 2279 binds to the alpha 1-adrenergic receptor with a Ki of 5 nM, and trimer CHIR 4531 binds to the mu-opiate receptor with a Ki of 6 nM. This represents the first example of the discovery of high-affinity receptor ligands from a combinatorial library of non-natural chemical entities. PMID:8064796

Zuckermann, R N; Martin, E J; Spellmeyer, D C; Stauber, G B; Shoemaker, K R; Kerr, J M; Figliozzi, G M; Goff, D A; Siani, M A; Simon, R J

1994-08-19

267

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

Directory of Open Access Journals (Sweden)

Full Text Available 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(OAc2/Pd2(dba3. The combination of Pd(OAc2, Xantphos, K2CO3 and dioxane was found to be crucial for the CO cross-coupling reaction. This is the first report on coupling of amides, amino acid esters and phenols with N-protected 4-bromo-7-azaindole derivatives.

Rajendra Surasani

2012-11-01

268

Discovery of N-substituted 3-arylisoquinolone derivatives as antitumor agents originating from O-substituted 3-arylisoquinolines via [2,3] or [3,3] rearrangement.  

Science.gov (United States)

The present study discovers multiple N-substituted 3-arylisoquinolone derivatives as antitumor agents originating from O-substituted 3-arylisoquinolines via [2,3] or [3,3] rearrangement. The current [2,3] rearrangement of epoxy or acetal O-substituents converting to diol or alcohol N-substituents can be promoted by silica gel or by diluted hydrochloric acid, which is distinct from previously reported [2,3] rearrangements. Some of the derivatives displayed comparable or even stronger cytotoxicity than sorafenib and vemurafenib on HCT116 colon carcinoma and A375 melanoma cell lines. Therefore, the rearrangement via intramolecular carbon-oxygen bond cleavage and carbon-nitrogen bond formation should be a useful approach for developing novel anticancer drugs derived from isoquinolones. PMID:24637214

Li, Bo; Wang, Gaihong; Xu, Zhijian; Zhang, Yong; Huang, Xiangui; Zeng, Bubing; Chen, Kaixian; Shi, Jiye; Wang, Heyao; Zhu, Weiliang

2014-04-22

269

N-Benzylhydroxylamine addition to beta-aryl enoates. Enantioselective synthesis of beta-aryl-beta-amino acid precursors  

Science.gov (United States)

Chiral Lewis acid catalyzed N-benzylhydroxylamine addition to pyrrolidinone-derived enoates afforded beta-aryl-beta-amino acid derivatives in high enantiomeric purity with moderate to very good chemical efficiency. PMID:11029219

Sibi; Liu

2000-10-19

270

Synthesis of Schiff bases of 2-amino-5-aryl-1,3,4-oxadiazoles and their evaluation for antimicrobial activities.  

Science.gov (United States)

Twenty Schiff bases of 2-amino-5-aryl-1,3,4-oxadiazoles have been synthesized with different aromatic aldehydes. The structures of the compounds were confirmed by nitrogen analysis, IR and 13C-NMR spectral data. The antibacterial properties of the compounds were investigated against Proteus mirabilis (MTCC-425), Pseudomonas aeruginosa (MTCC-424), Bacillus subtilis (MTCC-619) and Staphylococcus aureus (MTCC-96) using the broth dilution method. The most active compounds were 4c (64 microg/ml), 4f (68 microg/ml), 4m (64 microg/ml) and 4q (62 microg/ml). The antifungal screening of the compounds were carried out using Aspergillus niger (MTCC-1344) and Candida albicans (MTCC-227) using the broth dilution method. Active compounds were 4g (52 microg/ml), 4h (56 microg/ml), 4l (60 microg/ml), 4m (58 microg/ml). PMID:15942874

Mishra, Pradeep; Rajak, Harish; Mehta, Archana

2005-04-01

271

Comparison of Diffusion Coefficients of Aryl Carbonyls and Aryl Alcohols in Hydroxylic Solvents. Evidence that the Diffusion of Ketyl Radicals in Hydrogen-Bonding Solvents is Not Anomalous?  

Energy Technology Data Exchange (ETDEWEB)

The diffusion coefficients of a benzyl-, sec-phenethyl-, and diphenylmethyl alcohol and the corresponding aryl carbonyls (benzaldehyde, acetophenone and benzophenone) were measured by Taylor's dispersion method in both ethyl and isopropyl alcohol. The experimental values are compared to published transient grating measurements of the corresponding aryl ketyl radicals (benzyl-, sec-phenethyl-, and diphenylmethyl-ketyl radical). In general, the diffusion coefficient of the aryl alcohols and the corresponding aryl ketyl radicals are equivalent within experimental error. This work shows that the diffusion of ketyl radicals is not anomalously slow and that aryl alcohols are significantly better models than the corresponding aryl ketones for analyzing the diffusion of aryl ketyl radicals in both ethyl and isopropyl alcohol. Empirical estimates of the diffusion coefficients of aryl alcohols using the Spernol-Wirtz and Wilke-Chang modifications to the Stokes-Einstein diffusion equation do not adequately account for the interactions between the aryl ketyl radicals or aryl alcohols with the hydroxylic solvents ethyl and isopropyl alcohol. The excellent agreement between the experimental diffusion coefficients of the aryl alcohols and the corresponding ketyl radicals show that the transient grating method can provide accurate estimates for the diffusion coefficients of transient species. This is especially important when a stable model is not available, for example the pyranyl radical.

Autrey, S Thomas (BATTELLE (PACIFIC NW LAB)); Camaioni, Donald M.(BATTELLE (PACIFIC NW LAB)); Kandanarachchi, Pramod H.(ASSOC WESTERN UNIVERSITY); Franz, James A.(BATTELLE (PACIFIC NW LAB))

2000-12-01

272

Structural, spectroscopic, magnetic and electrochemical studies of monomer N-substituted-sulfanilamide copper (II) complex with 2,2'-bipyridine.  

Science.gov (United States)

A novel copper (II) complex of sulfamethazine (4-amino-N-[4,6-dimethyl-2-pyrimidinyl] benzene sulfonamide, Hsmz) ([Cu(smz)2bipy]?0.8H2O; bipy: 2,2'-bipyridine) has been synthesized and characterized by single crystal X-ray diffraction, EPR, IR, UV-vis and electrochemical methods. The single crystal X-ray analysis indicated that the compound crystallizes in the monoclinic space group P21/c with Z=4. The central copper (II) ion is coordinated by two bidentate sulfamethazine anions through the nitrogen atoms together with one bidentate 2,2'-bipyridine ligand forming the octahedral geometry. The characteristic vibration bands support the X-ray analysis results. The EPR spectral analysis has led to that the ground state wave function of the unpaired electron of copper ion is [Formula: see text] ((2)B1g state) and also indicated that the metal ions are located in distorted octahedral sites (D4h) elongated along the z-axis. The electrochemical studies of the complex were also carried out to determine the active sites of the ligands. The cyclic and square wave voltammetric techniques have been used to determine the complex. PMID:25459691

ztrk, Filiz; Bulut, ?clal; Bulut, Ahmet

2015-03-01

273

Boron compounds as anion binding agents for nonaqueous battery electrolytes  

Science.gov (United States)

Novel fluorinated boron-based compounds which act as anion receptors in non-aqueous battery electrolytes are provided. When added to non-aqueous battery electrolytes, the fluorinated boron-based compounds of the invention enhance ionic conductivity and cation transference number of non-aqueous electrolytes. The fluorinated boron-based anion receptors include borane and borate compounds bearing different fluorinated alkyl and aryl groups.

Lee, Hung Sui (East Setauket, NY); Yang, Xia-Oing (Port Jefferson Station, NY); McBreen, James (Bellport, NY); Xiang, Caili (Upton, NY)

2000-02-08

274

Synthesis and Antifungal Evaluation of 1-Aryl-2-dimethyl-aminomethyl-2-propen-1-one Hydrochlorides  

Directory of Open Access Journals (Sweden)

Full Text Available The development of resistance to current antifungal therapeutics drives the search for new effective agents. The fact that several acetophenone-derived Mannich bases had shown remarkable antifungal activities in our previous studies led us to design and synthesize some acetophenone-derived Mannich bases, 1-8 and 2-acetylthiophene-derived Mannich base 9, 1-aryl-2-dimethylaminomethyl-2-propen-1-one hydrochloride, to evaluate their antifungal activities. The designed chemical structures have ?,?-unsaturated ketone moieties, which are responsible for the bioactivities of the Mannich bases. The aryl part was C6H5 (1; 4-CH3C6H4 (2; 4-CH3OC6H4 (3; 4-ClC6H4 (4; 4-FC6H4 (5; 4-BrC6H4 (6; 4-HOC6H4 (7; 4-NO2C6H4 (8; and C4H3S(2-yl (9. In this study the designed compounds were synthesized by the conventional heating method and also by the microwave irradiation method to compare these methods in terms of reaction times and yields to find an optimum synthetic method, which can be applied for the synthesis of Mannich bases in further studies. Since there are limited number of studies reporting the synthesis of Mannich bases by microwave irradiation, this study may also contribute to the general literature on Mannich bases. Compound 7 was reported for the first time. Antifungal activities of all compounds and synthesis of the compounds by microwave irradiation were also reported for the first time by this study. Fungi (15 species were used for antifungal activity test. Amphotericin B was tested as an antifungal reference compound. In conclusion, compounds 1-6, and 9, which had more potent (216 times antifungal activity than the reference compound amphotericin B against some fungi, can be model compounds for further studies to develop new antifungal agents. In addition, microwave irradiation can be considered to reduce reaction period, while the conventional method can still be considered to obtain compounds with higher reaction yields in the synthesis of new Mannich bases.

Mehmet Emin Topaloglu

2011-06-01

275

Synthesis and antifungal evaluation of 1-aryl-2-dimethyl- aminomethyl-2-propen-1-one hydrochlorides.  

Science.gov (United States)

The development of resistance to current antifungal therapeutics drives the search for new effective agents. The fact that several acetophenone-derived Mannich bases had shown remarkable antifungal activities in our previous studies led us to design and synthesize some acetophenone-derived Mannich bases, 1-8 and 2-acetylthiophene-derived Mannich base 9, 1-aryl-2-dimethylaminomethyl-2-propen-1-one hydrochloride, to evaluate their antifungal activities. The designed chemical structures have ?,?-unsaturated ketone moieties, which are responsible for the bioactivities of the Mannich bases. The aryl part was C?H?(1); 4-CH?C?H? (2); 4-CH?OC?H? (3); 4-ClC?H? (4); 4-FC?H? (5); 4-BrC?H? (6); 4-HOC?H? (7); 4-NO?C?H? (8); and C?H?S(2-yl) (9). In this study the designed compounds were synthesized by the conventional heating method and also by the microwave irradiation method to compare these methods in terms of reaction times and yields to find an optimum synthetic method, which can be applied for the synthesis of Mannich bases in further studies. Since there are limited number of studies reporting the synthesis of Mannich bases by microwave irradiation, this study may also contribute to the general literature on Mannich bases. Compound 7 was reported for the first time. Antifungal activities of all compounds and synthesis of the compounds by microwave irradiation were also reported for the first time by this study. Fungi (15 species) were used for antifungal activity test. Amphotericin B was tested as an antifungal reference compound. In conclusion, compounds 1-6, and 9, which had more potent (2-16 times) antifungal activity than the reference compound amphotericin B against some fungi, can be model compounds for further studies to develop new antifungal agents. In addition, microwave irradiation can be considered to reduce reaction period, while the conventional method can still be considered to obtain compounds with higher reaction yields in the synthesis of new Mannich bases. PMID:21642940

Mete, Ebru; Gul, Halise Inci; Bilginer, Sinan; Algul, Oztekin; Topaloglu, Mehmet Emin; Gulluce, Medine; Kazaz, Cavit

2011-01-01

276

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

OpenAIRE

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

277

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

278

Tuning Aryl?CHO Intermolecular Interactions on Pt(111)  

DEFF Research Database (Denmark)

Scanning tunneling microscopy (STM) data are reported for the room-temperature adsorption of 2,2,2-trifluoroacetophenone (TFAP), 2,2,2-trifluorovinylbenzene (TFVB), octafluoroacetophenone (OFAP), and methyl benzoate (MB) on Pt(111). The objective of the study is to establish the role of aryl?CHO bonding in forming self-assembled low-nuclearity structures at room temperature and to compare aryl?CHO bonding by ester and ketone carbonyl functions. The STM images clearly evidence the formation of homochiral dimers and trimers of TFAP, and density functional theory (DFT) calculations reveal aryl?CHO bonding as the driving force for dimer formation. In contrast to TFAP, chemisorbed TFVB and OFAP do not form such self-assembled structures as they lack carbonyl and aryl?CH groups, respectively. The self-assembly of MB on Pt(111) differs from that of TFAP, in that it can form structures stabilized by one, as distinct from two, aryl?CHO bonds. The results are discussed with respect to the enantioselective hydrogenation of ?-ketoesters on cinchona modified Pt catalysts.

Demers-Carpentier, Vincent; Laliberte, Marc-Andre?

2011-01-01

279

Design, synthesis and protection against pentylenetetrazole-induced seizure of N-aryl derivatives of the phthalimide pharmacophore.  

Science.gov (United States)

A series of compounds including N-aryl substituents of phthalimide and 4-nitrophthalimide were synthesized and evaluated for their anticonvulsant properties. The in vivo screening data suggest that all the analogs have the ability to protect against pentylenetetrazole-induced seizures. These compounds exerted their maximal effects 30 min after administration. The most potent compound in both, tonic and clonic seizure was 1-naphthyl derivative (comp. 6), which was more active than the reference drug known as Phenytoin. Using an open pore model of the Na channel, these anticonvulsants were docked in the active site and examined in relation to the residues identified by mutagenesis as important for their binding energies. Docking studies revealed that all compounds (1-13) interacted mainly with residues II-S6 of NaV1.2 by making hydrogen bonds and additional hydrophobic interactions with domain I and II in the channel's inner pore. PMID:22741781

Davood, Asghar; Shafaroodi, Hamed; Amini, Mohsen; Nematollahi, Alireza; Shirazi, Mehrshad; Iman, Maryam

2012-09-01

280

Photoreactive molecular layers containing aryl ester units: Preparation, UV patterning and post-exposure modification  

International Nuclear Information System (INIS)

The photolithographic modification of thin functional silane layers provides a versatile and powerful means of fabricating functionalized patterned surfaces which can be applied for tuning inorganic surface properties and for modern immobilisation techniques. In this contribution we present the synthesis of a new functional trichloro organosilane bearing photoreactive aryl ester groups and its application in thin silane layers on silicon oxide surfaces. Whereas the trichlorosilyl group acts as anchoring unit to the inorganic surface, the aryl ester group undergoes the photo-Fries rearrangement to yield hydroxyketones upon irradiation with UV-light of 254 nm which leads to a change in chemical reactivity of the surface. By a subsequent reaction with perfluorobutyryl chloride, the photogenerated hydroxy groups yield the corresponding perfluorinated ester compound, which allows further tuning of surface properties. The layer formation as well as the photoreaction and post-modification reaction was monitored by FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). The thickness of the obtained thin layers was determined by X-ray reflectivity (XRR). Photopatterned surfaces were produced using a contact mask during illumination followed by the post-modification reaction. Friction force microscopy (FFM) revealed the contrast between modified and unmodified regions of the patterned samples.

281

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

282

Solvent switchable cycloaddition: a (one-pot) metal-free approach towards N-substituted benzo[e]- or [f]isoindolones via C(sp(2))-H functionalization.  

Science.gov (United States)

The tuning of selective ring closure is a nontrivial challenge in synthetic organic chemistry. Herein we report a solvent switchable metal-free [4 + 2] cycloaddition approach via Csp(2)-H functionalization. The protocol is highly atom economical with water being the only by-product, delivering N-substituted benzo[e]- or [f]isoindolones in high yields. PMID:25257733

Ambasana, Pratik A; Vachhani, Dipak D; Galli, Marzia; Jacobs, Jeroen; Van Meervelt, Luc; Shah, Anamik K; Van der Eycken, Erik V

2014-11-28

283

Nickel-catalyzed reductive coupling of aryl halides with secondary alkyl bromides and allylic acetate.  

Science.gov (United States)

A room-temperature Ni-catalyzed reductive method for the coupling of aryl bromides with secondary alkyl bromides has been developed, providing C(sp(2))-C(sp(3)) products in good to excellent yields. Slight modification of this protocol allows efficient coupling of activated aryl chlorides with cyclohexyl bromide and aryl bromides with allylic acetate. PMID:22697415

Wang, Shulin; Qian, Qun; Gong, Hegui

2012-07-01

284

Pd-Catalyzed Cross-Coupling Reactions of Amides and Aryl Mesylates  

OpenAIRE

A catalyst, based on a biarylphosphine ligand, for the Pd-catalyzed cross-coupling reactions of amides and aryl mesylates is described. This system allows an array of aryl and heteroaryl mesylates to be transformed into the corresponding N-aryl amides in moderate to excellent yields.

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

2010-01-01

285

Pd-Catalyzed N-Arylation of Secondary Acyclic Amides: Catalyst Development, Scope, and Computational Study  

OpenAIRE

We report the efficient N-arylation of acyclic secondary amides and related nucleophiles with aryl nonaflates, triflates, and chlorides. This method allows for easy variation of the aromatic component in tertiary aryl amides. A new biaryl phosphine with P-bound 3,5-(bis)trifluoromethylphenyl groups was found to be uniquely effective for this amidation. The critical aspects of the ...

Hicks, Jacqueline D.; Hyde, Alan M.; Cuezva, Alberto Martinez; Buchwald, Stephen L.

2009-01-01

286

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

OpenAIRE

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

287

Synthesis, insecticidal, and acaricidal activities of novel 2-aryl-pyrrole derivatives containing ester groups.  

Science.gov (United States)

A series of novel 2-aryl-pyrrole derivatives containing ester groups were synthesized, and their structures were characterized by (1)H NMR spectroscopy and elemental analysis. The insecticidal activities against oriental armyworm, mosquito, diamondback moth, green rice leafhopper, and bean aphids and acaricidal activities against spider mite of these new compounds were evaluated. The results of bioassays indicated that some of these title compounds exhibited excellent insecticidal and acaricidal activities. The insecticidal activities against oriental armyworm of compounds IVa, IVd, IVe, IVf, IVg, IVi, IVk, and IVp were equal to commercialized Chlorfenapyr, and the insecticidal activities of most of compounds IVb, IVc, IVd, IVf, IVg, IVj, IVk, IVl, IVs, IVt, IVu, IVw, IVx, IVz, and Chlorfenapyr against mosquito at 0.10 mg kg (-1) were 100%, and the acaricidal activities of compounds IVd, IVe, IVf, IVg, IVh, IVi, and IVk were equal or superior to Chlorfenapyr. Especially, the results indicated that the acaricidal activity of [4-bromo-2-(4-chlorophenyl)-3-cyano-5-(trifluoromethyl)pyrrol-1-yl]methyl 3-methylbutanoate ( IVg) against spider mite was 2.65-fold as high as that of Chlorfenapyr from the value of LC 50. PMID:18937487

Zhao, Yu; Li, Yongqiang; Ou, Xiaoming; Zhang, Pengxiang; Huang, Zhiqiang; Bi, Fuchun; Huang, Runqiu; Wang, Qingmin

2008-11-12

288

Sequential coupling approach to the synthesis of nickel(II) complexes with N-aryl-2-amino phenolates.  

Science.gov (United States)

A sequential multicomponent coupling approach is a powerful method for the construction of combinatorial libraries because structurally complex and diverse molecules can be synthesized from simple materials in short steps. In this paper, an efficient synthesis of nickel(II) complexes with N-aryl-2-amino phenols via a sequential three-step coupling approach is described, for potential use in nonlinear optical materials, bioinspired catalytic systems, and near-infrared absorbing filters. Seventeen N-aryl-2-amino phenolates were successfully synthesized in high yields based on the coupling of 3,5-di-tert-butylbenzene-1,2-diol with a pivotal aromatic scaffold, 4-bromo-2-iodo-aniline, followed by sequential Suzuki-Miyaura coupling with aryl boronates. A total of 16 analytically pure nickel(II) complexes with N-aryl-2-amino phenolates were obtained from 17 complexation trials. The procedure allowed us to assemble 4 components in high yields without protection, deprotection, oxidation or reduction steps. Various building blocks that included electron-donating, electron-withdrawing, and basic were used, and readily available, nontoxic and environmentally benign substrates and reagents were employed with no generation of toxic compounds. No strict anhydrous or degassed conditions were required. Absorption spectroscopic measurement of the synthesized nickel(II) complexes revealed that the ortho-substituent Ar(1) exerted more influence on the absorption wavelength of the complexes than the para-substituent Ar(2). On the other hand, both substituents Ar(1) and Ar(2) influenced the molar absorptivity values. These observations should be useful for the design of new and useful nickel(II) complexes as near-infrared chromophores. PMID:22916832

Fuse, Shinichiro; Tago, Hiroaki; Maitani, Masato M; Wada, Yuji; Takahashi, Takashi

2012-10-01

289

Investigating the proteome reactivity and selectivity of aryl halides.  

Science.gov (United States)

Protein-reactive electrophiles are critical to chemical proteomic applications including activity-based protein profiling, site-selective protein modification, and covalent inhibitor development. Here, we explore the protein reactivity of a panel of aryl halides that function through a nucleophilic aromatic substitution (S(N)Ar) mechanism. We show that the reactivity of these electrophiles can be finely tuned by varying the substituents on the aryl ring. We identify p-chloro- and fluoronitrobenzenes and dichlorotriazines as covalent protein modifiers at low micromolar concentrations. Interestingly, investigating the site of labeling of these electrophiles within complex proteomes identified p-chloronitrobenzene as highly cysteine selective, whereas the dichlorotriazine favored reactivity with lysines. These studies illustrate the diverse reactivity and amino-acid selectivity of aryl halides and enable the future application of this class of electrophiles in chemical proteomics. PMID:24548313

Shannon, D Alexander; Banerjee, Ranjan; Webster, Elizabeth R; Bak, Daniel W; Wang, Chu; Weerapana, Eranthie

2014-03-01

290

Synthesis and identification of novel 11beta-aryl-4',5'-dihydrospiro[estra-4,9-diene-17beta,4'-oxazole] analogs with dissociated antiprogesterone activities.  

Science.gov (United States)

A series of novel 11beta-aryl-4',5'-dihydrospiro[estra-4,9-diene-17beta,4'-oxazole] analogs have been evaluated for their antagonist hormonal properties using the T47D cell-based alkaline phosphatase assay and the A549 cell-based functional assay. Some of the compounds showed highly potent, and more selective antiprogestational activity against antiglucocorticoid activity than mifepristone (RU 486). PMID:17855092

Jin, Chunyang; Manikumar, G; Kepler, John A; Cook, C Edgar; Allan, George F; Kiddoe, Margaret; Bhattacharjee, Sheela; Linton, Olivia; Lundeen, Scott G; Sui, Zhihua

2007-11-01

291

Pd-Catalyzed Cross-Coupling of Aryllithium Reagents with 2-Alkoxy-Substituted Aryl Chlorides: Mild and Efficient Synthesis of 3,3'-Diaryl BINOLs.  

Science.gov (United States)

Palladium-catalyzed cross-coupling of aryllithium reagents with 2-alkoxy-substituted aryl chlorides is described. The reactions proceed under mild conditions with short reaction times and provide a wide range of 2-alkoxy-substituted biaryls. This new methodology is applied to the efficient preparation of 3,3'-diaryl BINOLs and represents the first synthesis of this important class of chiral compounds from the corresponding 3,3'-dichloro BINOLs. PMID:25514438

Castell, Luis M; Hornillos, Valentn; Vila, Carlos; Giannerini, Massimo; Faans-Mastral, Martn; Feringa, Ben L

2015-01-01

292

Palladium-catalyzed direct arylation of pyridine N-oxide with 2-bromoacetanilides. Synthesis of benzisoxazolo[2,3-a]pyridinium tetrafluoroborates  

OpenAIRE

The synthesis of a variety of novel benzisoxazolo[2,3-a]pyridinium tetrafluoroborates is described. These compounds are conveniently prepared from pyridine N-oxide via a microwave-promoted palladium-catalyzed direct arylation of pyridine N-oxide with 2-bromoacetanilides to give 2-(2-acetamidoaryl)pyridine N-oxides, followed by hydrolysis, diazotization and intramolecular displacement of nitrogen which affords the target benzisoxazolo[2,3-a]pyridinium tetrafluoroborates.

Myers, Jeffery T.; Hanna, James M.

2012-01-01

293

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

294

Mesomorphic Poly(aryl ester)/Poly(benzyl ether) Dendrimers/co-Dendrimers with C60 as the Core  

OpenAIRE

Structure-properties relations of liquid crystalline fullerene-containing poly(aryl ester)/poly(benzyl ether) dendritic compounds with variation of C60 linkage type have been analyzed based on experimental data on their total polarity and electrooptical Kerr effect in benzene solutions. There was established that fulleropyrrolidine as the core of dendrimer strongly restricts rotational freedom of dendrons, in contrast to methanofullerene. A conclusion that not only terminal meso...

Yevlampieva, Natalia; Beljaev, Nikolai; Lavrenko, Peter; Deschenaux, Robert

2011-01-01

295

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

OpenAIRE

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

296

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

297

Palladium-catalyzed amination of aryl chlorides and bromides with ammonium salts.  

Science.gov (United States)

We report the palladium-catalyzed coupling of aryl halides with ammonia and gaseous amines as their ammonium salts. The coupling of aryl chlorides and ortho-substituted aryl bromides with ammonium sulfate forms anilines with higher selectivity for the primary arylamine over the diarylamine than couplings with ammonia in dioxane. The resting state for the reactions of aryl chlorides is different from the resting state for the reactions of aryl bromides, and this change in resting states is proposed to account for a difference in selectivities for reactions of the two haloarenes. PMID:25133675

Green, Rebecca A; Hartwig, John F

2014-09-01

298

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

299

Discovery of C-(1-aryl-cyclohexyl)-methylamines as selective, orally available inhibitors of dipeptidyl peptidase IV.  

Science.gov (United States)

The successful launches of dipeptidyl peptidase IV (DPP IV) inhibitors as oral anti-diabetics warrant and spur the further quest for additional chemical entities in this promising class of therapeutics. Numerous pharmaceutical companies have pursued their proprietary candidates towards the clinic, resulting in a large body of published chemical structures associated with DPP IV. Herein, we report the discovery of a novel chemotype for DPP IV inhibition based on the C-(1-aryl-cyclohexyl)-methylamine scaffold and its optimization to compounds which selectively inhibit DPP IV at low-nM potency and exhibit an excellent oral pharmacokinetic profile in the rat. PMID:24439847

Namoto, Kenji; Sirockin, Finton; Ostermann, Nils; Gessier, Francois; Flohr, Stefanie; Sedrani, Richard; Gerhartz, Bernd; Trappe, Jrg; Hassiepen, Ulrich; Duttaroy, Alokesh; Ferreira, Suzie; Sutton, Jon M; Clark, David E; Fenton, Garry; Beswick, Mandy; Baeschlin, Daniel K

2014-02-01

300

Double N-arylation reaction of polyhalogenated 4,4-bipyridines. Expedious synthesis of functionalized 2,7-diazacarbazoles  

Directory of Open Access Journals (Sweden)

Full Text Available Unusual 2,7-diazacarbazoles were prepared in one step from readily available tetra-halogenated 4,4-bipyridines by using a double N-arylation reaction in the presence of the PdXPhos catalyst system. Moderate to good yields were obtained in this site-selective BuchwaldHartwig double amination. The functionalization of these tricyclic derivatives was performed by using Pd-catalyzed cross-coupling reactions such as the Stille and Suzuki couplings. Two compounds were analyzed by X-ray diffraction and show ?? stacking involving the diazacarbazole moieties and the phenyl rings of functionalized groups.

Mohamed Abboud

2012-02-01

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

302

An LFER study of the protolytic equilibria of 4-aryl-2,4-dioxobutanoic acids in aqueous solutions  

OpenAIRE

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 consta...

Verbic, Tatjana Z.; Drakulic, Branko J.; Zloh, Mire F.; Pecelj, Jovana R.; Popovic, Gordana V.; Juranic, Ivan O.

2007-01-01

303

Role of the Per/Arnt/Sim Domains in Ligand-dependent Transformation of the Aryl Hydrocarbon Receptor*S?  

OpenAIRE

The aryl hydrocarbon receptor (AhR) mediates the toxic and biological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and related compounds. In a process termed transformation, ligand binding converts the AhR into its high affinity DNA binding form that represents a dimer of the AhR and Arnt, a closely related nuclear protein. During transformation, protein chaperone Hsp90 is thought to be replaced by Arnt in overlapping binding sites in the basic helix loop helix and P...

Soshilov, Anatoly; Denison, Michael S.

2008-01-01

304

Design and development of POCN-pincer palladium catalysts for C-H bond arylation of azoles with aryl iodides.  

Science.gov (United States)

Well-defined and efficient POCN-ligated palladium complexes have been developed for the direct C-H bond arylation of azoles with aryl iodides. The phosphinite-amine pincer ligands 1-(R2PO)-C6H4-3-(CH2N(i)Pr2) [(R2)POCN(iPr2)-H; R = (i)Pr (), R = (t)Bu ()] and corresponding palladium complexes {2-(R2PO)-C6H3-6-(CH2N(i)Pr2)}PdCl [((R2)POCN(iPr2))PdCl; R = (i)Pr (), R = (t)Bu ()] were synthesized in good yields. Treatment of palladium complex with KI and AgOAc afforded the complexes ((iPr2)POCN(iPr2))PdI () and ((iPr2)POCN(iPr2))Pd(OAc) (), respectively. Similarly, the reaction of with benzothiazolyl-lithium produces the ((iPr2)POCN(iPr2))Pd(benzothiazolyl) () complex in a quantitative yield. The pincer palladium complex efficiently catalyzes the C-H bond arylation of benzothiazole, substituted-benzoxazoles and 5-aryl oxazoles with diverse aryl iodides in the presence of CuI as a co-catalyst under mild reaction conditions. This represents the first example of a pincer palladium complex being applied for the direct C-H bond arylation of any heterocycle with low catalyst loading. A preliminary mechanistic investigation reveals that palladium nanoparticles are presumably not the catalytically active form of and supports the direct involvement of the catalyst , with complex being a probable key intermediate in the catalytic reaction. PMID:25238444

Khake, Shrikant M; Soni, Vineeta; Gonnade, Rajesh G; Punji, Benudhar

2014-11-14

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

Mannosylated N-aryl substituted 3-hydroxypyridine-4-ones: synthesis, hemagglutination inhibitory properties, and molecular modeling.  

Science.gov (United States)

Structural alterations of the aglycon portions of ?-mannosides influence their inhibitory potency toward type 1-fimbriated Escherichia coli. The aim of our work was to prepare and explore inhibitory properties of novel mannosylated N-aryl-substituted 3-hydroxypyridine-4-ones because they possess needed structural characteristics as possible FimH antagonists. Hemagglutination inhibitory tests showed that the examined 3-hydroxypyridine-4-one ?-mannosides exhibited better inhibitory activity than methyl ?-d-mannopyranoside used as a reference compound. Molecular modeling studies revealed the specific interactions responsible for the observed binding activities toward the mannose-specific FimH lectin. The activity depends on the substituent in p-position on the aglycon aromatic ring. PMID:24674669

Car, Zeljka; Hrenar, Tomica; Petrovi? Perokovi?, Vesna; Ribi?, Rosana; Seni?ar, Mateja; Tomi?, Sr?anka

2014-10-01

307

Synthesis, Characterization and Biological Screening of Various O-phenyl-N-aryl Carbamates  

International Nuclear Information System (INIS)

A series of O-phenyl-N-aryl carbamates (3a-i) were synthesized by the reaction of phenyl chloroformate (1) with different aromatic amines (2a-i). The compounds were characterized by IR and 1H-NMR and screened against acetylcholinesterase, butrylcholinesterase and lipoxygenase enzymes. The results revealed that O-phenyl-N-phenyl carbamate (3a) and O-phenyl-N-(3-hydroxyphenyl) carbamate (3e) were active against acetylcholinesterase while O-phenyl-N-benzyl carbamate (3b), O-phenyl-N-(4-hydroxyphenyl) carbamate (3f) and O-phenyl-N-(3-methoxyphenyl) carbamate (3h) exhibited potential inhibitory activity against 5-lipoxygenase. All these carbamates were also assayed for their antimicrobial and hemolytic activities. O-phenyl-N-(2-hydroxyphenyl) carbamate (3d), O-phenyl-N-(4-hydroxyphenyl) carbamate (3f) and O-phenyl-N-(3-methoxyphenyl) carbamate (3h) showed good antimicrobial and hemolytic activity among all the carbamates. (author)

308

Novel 3-substituted-1-aryl-5-phenyl-6-anilinopyrazolo[3,4-d]pyrimidin-4-ones: docking, synthesis and pharmacological evaluation as a potential anti-inflammatory agents.  

Science.gov (United States)

Novel 3-substituted-1-aryl-5-phenyl-6-anilino-pyrazolo[3,4-d]pyrimidin-4-ones of pharmacological significance were synthesized by the reaction of ethyl-(5-amino-3-methylthio-1-aryl-5-phenyl-2H-pyrazole)-4-carboxylates 3a-c with S-methyl diphenyl thiourea independently to produce 1-aryl-3-thiomethyl-5-phenyl-pyrazolo[3,4-d]pyrimidines 4a-c in DMF with catalytic amount of K(2)CO(3), which on further treatment with different aromatic amines independently under same reaction conditions generated for compounds 5a-l. The compounds were screened for the anti-inflammatory activity and evaluated for ulcerogenic potential. The compounds 5i exhibited superior anti-inflammatory activity in comparison with diclofenac sodium and comparable activity with celecoxib at a dose of 25mg/kg. The other compounds 4c, 5c, 5f and 5l were found as active with inhibition of edema in the range of 35-39 after 3 h of administration of test compounds. The ulcerogenic potential of active compounds was observed to be quite lesser as compared to standard. COX-2 docking score of the active compound 5i was found to be better than standard celecoxib. PMID:23036953

Yewale, Sandeep B; Ganorkar, Saurabh B; Baheti, Kamalkishor G; Shelke, Rupesh U

2012-11-01

309

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

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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

310

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

Science.gov (United States)

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. PMID:25134761

Pervez, Humayun; Saira, Naveeda; Iqbal, Mohammad Saeed; Yaqub, Muhammad; Khan, Khalid Mohammed

2011-01-01

311

Solution studies of organolithium compounds and organomagnesium compounds  

International Nuclear Information System (INIS)

The solution structure of 2,2'-dilithiobiphenyl in diethyl ether was determined using the isotopic substitution method and spin lattice relaxation times. Internuclear distances r[Li-C(1)] and r[Li-H(3)] were calculated from the dipole-dipole contribution to the spin lattice relaxation times of the 6Li/7Li isotopomers of selectively deuterated dilithiobiphenyl compounds. From the established internuclear distances, it was determined that 2,2'-dilithiobiphenyl in diethyl ether exists not as a monomer as seen in the x-ray crystal structure, but as a dimer. The reaction of diorganomagnesium compounds with cryptands and crown ethers results in disproportionation to form magnesiate ions and RMg(cryptand)+ or RMg(crown)+. Disproportionation is observed for primary, secondary and tertiary diorganomagnesium compounds. Reactions of diarylmagnesium compounds with cryptands results in the formation of magnesiate ions and ArMg(cryptand)+. Reactions of diarylmagnesium compounds with 15-crown-5 and 18-crown-6 produced unexpected results. The 1H NMR spectra of solutions prepared from initial ratios of 2Mg to crown ether exhibited absorptions which were attributed to a threaded species, Ar2Mg(crown). The magnesium atom is encircled by the crown ether and bonded to two apical aryl groups. Ar2Mg(18-crown-6) reacts slowly with ketones, which is unusual for an organomagnesium compound. unusual for an organomagnesium compound. At ratios >3, solutions of the more soluble diarylmagnesium compounds and crown ethers show evidence of disproportionation

312

Synthesis of tetraiodocadmoates of di-p-tolylethylamidomethylalkyl(aryl)-arsonium  

International Nuclear Information System (INIS)

By interaction of cadmium iodide aqueous solution with di-p-tolylethylamidomethylalkyl (aryl)-arsonium salts tetraiodocadmoates are synthesized. Composition and structure of synthesized complexes are investigated by the methods of IR-srectroscopy, element analysis. The data on the yields of synthesis reactions, synthesized substances melting points are presented

313

N-Aryl azacycles as novel sodium channel blockers.  

Science.gov (United States)

We have identified a new series of N-aryl azacycles as sodium channel blockers, which showed good potency on Nav1.7 in FLIPR-based and electrophysiological functional assays. Analogs from this series possessed selectivity over hERG, reasonable oral exposure in rat PK studies and are predicted to have limited CNS penetration. PMID:25435147

Lynch, Stephen M; Tafesse, Laykea; Carlin, Kevin; Ghatak, Parijat; Shao, Bin; Abdelhamid, Haissam; Kyle, Donald J

2015-01-01

314

Palladium-catalyzed arylation of styrene in water  

International Nuclear Information System (INIS)

Palladium-catalyzed arylation of water-soluble olefins by arylhalides (Heck reaction) is described. Styrene reacts with aryliodides at 100 deg in Na2CO3 or K2CO3 aqueous solution during Pd(OAc)2 catalysis in the presence of small amount of Bu3N with formation of substituted stilbenes

315

Plastic components affect the activation of the aryl hydrocarbon and the androgen receptor.  

Science.gov (United States)

Phenols and plasticizers are widely used in the plastic industry, in food packaging and to impart softness and flexibility to normally rigid plastic medical devices and children's toys. The effects on the aryl hydrocarbon receptor (AhR) and the androgen receptor (AR) were assessed using luciferase reporter gene assays of the following compounds: bisphenol A (BPA), 4-n-nonylphenol (nNP), 4-tert-octylphenol (tOP), bis(2-ethylhexyl) phthalate (DEHP), di-isononyl phthalate (DINP), diisodecyl phthalate (DIDP), di-n-octyl phthalate (DNOP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), 4-chloro-3-methylphenol (CMP), 2-phenylphenol (2-PP), 2,4-dichlorophenol (DCP), resorcinol and bis(2-ethylhexyl) adipate (DEHA). Furthermore, a mixture of selected compounds was tested at the no-observed-effect concentration (NOEC), the low-observed-effect concentration (LOEC) and the half-maximum-effect/inhibitory concentration (EC50/IC50) of the single chemicals. Both receptors were affected by BPA, nNP, BBP, CMP, DCP and resorcinol whereas DEHP, DIDP and DBP affected only the AhR and tOP and 2-PP antagonised the AR activity. The mixture was composed of 6 compounds, of which one compound weakly induced the AhR but all compounds antagonized the AR activation. Using the concentration addition principle additive effects were observed at the NOEC, LOEC and EC50/IC50 for both receptors. Our in vitro data suggest that the effect of a mixture depends on the concentration, character, potency and composition of the single mixture compounds and that also the combined effects of the compounds should be taken into consideration for risk assessment of human health. PMID:18294747

Krger, Tanja; Long, Manhai; Bonefeld-Jrgensen, Eva C

2008-04-18

316

[(Salcen)Cr(III) + Lewis base]-catalyzed synthesis of N-aryl-substituted oxazolidinones from epoxides and aryl isocyanates.  

Science.gov (United States)

[(Salcen)Cr(III) + Lewis base] was found to be a highly active and selective catalyst system in the [2+3] cycloaddition between epoxides and isocyanates to form 5-oxazolidinones. The reaction proceeds to high yield under mild reaction conditions and is applicable to a variety of terminal epoxides and aryl isocyanates. PMID:25336244

Paddock, Robert L; Adhikari, Debashis; Lord, Richard L; Baik, Mu-Hyun; Nguyen, SonBinh T

2014-12-14

317

Biaryl and aryl ketone synthesis via Pd-catalyzed decarboxylative coupling of carboxylate salts with aryl triflates.  

Science.gov (United States)

A bimetallic catalyst system has been developed that for the first time allows the decarboxylative cross-coupling of aryl and acyl carboxylates with aryl triflates. In contrast to aryl halides, these electrophiles give rise to non-coordinating anions as byproducts, which do not interfere with the decarboxylation step that leads to the generation of the carbon nucleophilic cross-coupling partner. As a result, the scope of carboxylate substrates usable in this transformation was extended from ortho-substituted or otherwise activated derivatives to a broad range of ortho-, meta-, and para-substituted aromatic carboxylates. Two alternative protocols have been optimized, one involving heating the substrates in the presence of Cu(I)/1,10-phenanthroline (10-15 mol %) and PdI(2)/phosphine (2-3 mol %) in NMP for 1-24 h, the other involving Cu(I)/1,10-phenanthroline (6-15 mol %) and PdBr(2)/Tol-BINAP (2 mol %) in NMP using microwave heating for 5-10 min. While most products are accessible using standard heating, the use of microwave irradiation was found to be beneficial especially for the conversion of non-activated carboxylates with functionalized aryl triflates. The synthetic utility of the transformation is demonstrated with 48 examples showing the scope and limitations of both protocols. In mechanistic studies, the special role of microwave irradiation is elucidated, and further perspectives of decarboxylative cross-couplings are discussed. PMID:19718720

Goossen, Lukas J; Linder, Christophe; Rodrguez, Nuria; Lange, Paul P

2009-09-21

318

Continuous flow enantioselective arylation of aldehydes with ArZnEt using triarylboroxins as the ultimate source of aryl groups  

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Full Text Available A continuous flow system for the synthesis of enantioenriched diarylmethanols from aldehydes is described. The system uses an amino alcohol-functionalized polystyrene resin as the catalyst, and the arylating agent is conveniently prepared by transmetallation of triarylboroxins with diethylzinc.

Julien Rolland

2009-10-01

319

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

320

In vitro evaluation of anti-pathogenic surface coating nanofluid, obtained by combining Fe3O4/C12 nanostructures and 2-((4-ethylphenoxy)methyl)-N-(substituted-phenylcarbamothioyl)-benzamides  

OpenAIRE

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 a...

Anghel, Ion; Limban, Carmen; Grumezescu, Alexandru Mihai; Anghel, Alina Georgiana; Bleotu, Coralia; Chifiriuc, Mariana Carmen

2012-01-01

321

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

322

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

323

[Imidazo(2,1-b)thiazole XII derivatives. Synthesis and research of immunoactivity in vitro on human T lymphocyte of 3-aroylmethyl and 2-aroyl-3-methyl(aryl)-5,6-dihydroimidaz o(2,1-b)thiazoles].  

Science.gov (United States)

To estimate the influence of aryl group position on the immunostimulant properties of imidazo[2,1-b]thiazole derivatives, several compounds were obtained and tested, versus tetramisole hydrochloride, on the mobilisation of CD2 receptor by human T lymphocyte. The synthesis use the action of monobrominated beta-diketones on the 2-mercaptoimidazoline. So, 1-aryl-4-bromobutane-1,3-diones lead to 3-aroylmethyl-5,6-dihydroimidazo[2,1-b]thiazoles 4. Same, 1-aryl-2-bromobutane-1,3-diones and 1,3-diaryl-2-bromopentane-1,3-diones give respectively 3-aroyl-2-methyl-5,6-dihydroimidazo[2,1-b]thiazoles 5 and 3-aroyl-2-aryl-5,6-dihydroimidazo[2,1-b]thiazoles 6. Better yields are obtained when the reaction presents two steps. The first one, realized in acetone at room temperature, leads to an intermediate S-substituted 4,5-dihydroimidazole which, in second step, is cyclized in imidazo[2,1-b]thiazole compound via an unisolated carbinolamine. This one explains the univocal formation of 5 derivatives and the feasible blending in case of 6. The immunoactivity of several imidazothiazoles 4, 5 and 6 is lower that them of 6-aryl substituted compounds and particularly that the levamisole which is the reference product in this series. PMID:8572506

Robert, J F; Hassanine, A; Harraga, S; Seilles, E

1995-01-01

324

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

325

Nickel-Mediated Hydrogenolysis of C-O Bonds of Aryl Ethers: What Is the Source of the Hydrogen?  

OpenAIRE

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

326

Novel haloperoxidase from the agaric basidiomycete Agrocybe aegerita oxidizes aryl alcohols and aldehydes.  

Science.gov (United States)

Agrocybe aegerita, a bark mulch- and wood-colonizing basidiomycete, was found to produce a peroxidase (AaP) that oxidizes aryl alcohols, such as veratryl and benzyl alcohols, into the corresponding aldehydes and then into benzoic acids. The enzyme also catalyzed the oxidation of typical peroxidase substrates, such as 2,6-dimethoxyphenol (DMP) or 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS). A. aegerita peroxidase production depended on the concentration of organic nitrogen in the medium, and highest enzyme levels were detected in the presence of soybean meal. Two fractions of the enzyme, AaP I and AaP II, which had identical molecular masses (46 kDa) and isoelectric points of 4.6 to 5.4 and 4.9 to 5.6, respectively (corresponding to six different isoforms), were identified after several steps of purification, including anion- and cation-exchange chromatography. The optimum pH for the oxidation of aryl alcohols was found to be around 7, and the enzyme required relatively high concentrations of H(2)O(2) (2 mM) for optimum activity. The apparent K(m) values for ABTS, DMP, benzyl alcohol, veratryl alcohol, and H(2)O(2) were 37, 298, 1,001, 2,367 and 1,313 microM, respectively. The N-terminal amino acid sequences of the main AaP II spots blotted after two-dimensional gel electrophoresis were almost identical and exhibited almost no homology to the sequences of other peroxidases from basidiomycetes, but they shared the first three amino acids, as well as two additional amino acids, with the heme chloroperoxidase (CPO) from the ascomycete Caldariomyces fumago. This finding is consistent with the fact that AaP halogenates monochlorodimedone, the specific substrate of CPO. The existence of haloperoxidases in basidiomycetous fungi may be of general significance for the natural formation of chlorinated organic compounds in forest soils. PMID:15294788

Ullrich, Ren; Nske, Jrg; Scheibner, Katrin; Spantzel, Jrg; Hofrichter, Martin

2004-08-01

327

Divergent Reaction Pathways for Phenol Arylation by Arynes: Synthesis of Helicenes and 2-Arylphenols  

Science.gov (United States)

Two reactions of phenols with arynes have been developed. If LiTMP base is employed, arynes generated from aryl chlorides react with phenols to form helicenes. o-Arylation of phenols can be achieved by employing tBuONa base in the presence of AgOAc. Direct arylation of binol was achieved leading to the shortest pathway to o,o-diarylbinols. PMID:24077102

Truong, Thanh; Daugulis, Olafs

2013-01-01

328

Palladium(ii)-catalyzed meta-selective direct arylation of O-?-naphthyl carbamate.  

Science.gov (United States)

Selective meta-arylation of O-?-naphthyl carbamate has been accomplished using Pd(OAc)2 as a catalyst precursor and K2S2O8 with AgOAc as the oxidant. A range of aryl boronic acids could be introduced in moderate to good yields. Mechanistic investigation shows that the carbamate substituent has a unique effect and the reaction undergoes an ortho-carbometallation/meta-direct arylation process. PMID:25478680

Zhang, Jingchang; Liu, Qingwen; Liu, Xufei; Zhang, Suoqin; Jiang, Pingping; Wang, Yanxiang; Luo, Shengyuan; Li, Yang; Wang, Qifeng

2014-12-01

329

Divergent Reaction Pathways for Phenol Arylation by Arynes: Synthesis of Helicenes and 2-Arylphenols  

OpenAIRE

Two reactions of phenols with arynes have been developed. If LiTMP base is employed, arynes generated from aryl chlorides react with phenols to form helicenes. o-Arylation of phenols can be achieved by employing tBuONa base in the presence of AgOAc. Direct arylation of binol was achieved leading to the shortest pathway to o,o-diarylbinols.

Truong, Thanh; Daugulis, Olafs

2012-01-01

330

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

331

Radical arylation of phenols, phenyl ethers, and furans.  

Science.gov (United States)

Radical arylations of para-substituted phenols and phenyl ethers proceeded with good regioselectivity at the ortho position with respect to the hydroxy or alkoxy group. The reactions were conducted with arenediazonium salts as the aryl radical source, titanium(III) chloride as the reductant, and diluted hydrochloric acid as the solvent. Substituted biaryls were obtained from hydroxy- and alkoxy-substituted benzylamines, phenethylamines, and aromatic amino acids. The methodology described offers a fast, efficient, and cost-effective new access to diversely functionalized biphenyl alcohols and ethers. Free phenolic hydroxy groups, aromatic and aliphatic amines, as well as amino acid substructures, are well tolerated. Two examples for the applicability of the methodology are the partial synthesis of a beta-secretase inhibitor and the synthesis of a calcium-channel modulator. PMID:20066707

Wetzel, Alexander; Pratsch, Gerald; Kolb, Roman; Heinrich, Markus R

2010-02-22

332

The genetics of the aryl sulfatase a locus  

OpenAIRE

A genetic analysis was performed in an isolate in which metachromatic leukodystrophy (MLD) and aryl sulfatase A (ASA) pseudodeficiency are relatively frequent. The frequency of matings at risk and the frequency of ASA pseudodeficiency among parents of MLD patients are compatible with allelism between the gene determining MLD and the gene determining ASA pseudodeficiency. Two independent pedigrees including MLD patients and ASA-deficient healthy individuals also fit the model of allelism.

Schaap, T.; Zlotogora, J.; Elian, E.; Barak, Y.; Bach, G.

1981-01-01

333

Aryl Polyphosphonates: Useful Halogen-Free Flame Retardants for Polymers  

OpenAIRE

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-re...

Li Chen; Yu-Zhong Wang

2010-01-01

334

Preparation of Aryl-Susbstituted 2-Oxyindoles by Superelectrophilic Chemistry  

OpenAIRE

A series of pyridyl-substituted 3-hydroxy-2-oxyindoles have been prepared and reacted with arenes in superacid promoted Friedel-Crafts reactions. The product aryl-substituted 2-oxyindoles are formed in generally good yields. With substituted arenes such as toluene, bromobenzene, or ethyl salicylate, the Friedel-Crafts reactions occur with excellent regioselectivity. A mechanism is proposed involving dicationic, superelectrophilic species leading to the electrophilic aromatic substitution chem...

Naredla, Rajasekhar Reddy; Raja, Erum K.; Klumpp, Douglas A.

2013-01-01

335

Catalytic asymmetric Diels-Alder reactions involving aryl vinyl ketones.  

Science.gov (United States)

A catalytic asymmetric Diels-Alder reaction of an aryl vinyl ketone with 1,3-dienylcarbamate has been developed. Cyclohexenes bearing vicinal amino and aroyl groups in a cis-configuration were prepared in excellent ee (>99%) and endo (single diastereomer) selectivity. The absolute configuration of one DA product was unambiguously confirmed using XRD analysis. The transition state structure was proposed on the basis of DFT calculations. PMID:25271484

Kong, Liman; Han, Xiaoyu; Jiao, Peng

2014-11-25

336

Regioselectivity of Arylation of 2,3’-Biquinolyl Dianion  

OpenAIRE

The dianion of 2,3’-biquinolyl with aryl- and hetaryl halides forms the products of arylation to 4’-position, which on treatment with alkyl halides or water yield 1’-alkyl-1’,4’dihydro-2,3’-biquinolyls or 4’-aryl-1’,4’-dihydro-2,3’-biquinolyls respectively. The oxidation of the latter leads to 4’-aryl-2,3’-biquinolyls. The cation dependenc...

Smushkevich, Yu I.; Borovlev, I. V.; Aksenova, I. V.; Aksenov, A. V.

1999-01-01

337

Aryl-aldehyde formation in fungal polyketides: discovery and characterization of a distinct biosynthetic mechanism.  

Science.gov (United States)

Aryl-aldehydes are a common feature in fungal polyketides, which are considered to be exclusively generated by the R domain of nonreducing polyketide synthases (NR-PKSs). However, by cloning and heterologous expression of both cryptic NR-PKS and nonribosomal peptide synthase (NRPS)-like genes from Aspergillus terreus in Saccharomyces cerevisiae, we identified a distinct mechanism for aryl-aldehyde formation in which a NRPS-like protein activates and reduces an aryl-acid produced by the accompanying NR-PKS to an aryl-aldehyde. Bioinformatics study indicates that such a mechanism may be widely used throughout the fungi kingdom. PMID:24412543

Wang, Meng; Beissner, Mirko; Zhao, Huimin

2014-02-20

338

Influence of the structure of bidentate organophosphorus compounds and their extraction capacity  

International Nuclear Information System (INIS)

This paper studies the variation of the extraction capacity within a broad series of didentate organophosphorus compounds, from diphosphine dioxides to carbamoylphosphine oxides and phosphonates. The authors consider the disputed questions of the coordination of the actinides when carbamoyl compounds are used and they consider whether an effect of anomalous aryl strenghening exists in these systems. The compounds used are presented. The extraction of microquantities of americium and other actinides was performed from nitric acid media

339

Synthesis of 1-Aryl-3-phenethylamino-1-propanone Hydrochlorides as Possible Potent Cytotoxic Agents  

Directory of Open Access Journals (Sweden)

Full Text Available 1-Aryl-3-phenethylamino-1-propanone hydrochlorides 1-10, which are potentialpotent cytotoxic agents, were synthesized via Mannich reactions using paraformaldehyde,phenethylamine hydrochloride as the amine component and acetophenone, 4’-methyl-, 4’-methoxy-, 4’-chloro-, 4’-fluoro-, 4’-bromo-, 2’,4’-dichloro-, 4’-nitro-, 4’-hydroxyacetophenone or 2-acetylthiophene as the ketone component. Yields were in the87-98 % range. Of the compounds synthesized, compounds 2, 6-8 and 10 were new. Theoptimum reaction conditions were investigated by changing the mol ratios of the reactants,the solvents and the acidity levels using 1 and 10 as representative targets. It was observedthat the best mol ratio of the ketone, paraformaldehyde and phenethylamine hydrochloridewas 1:1.2:1 (compared with a 2:2.1 ratio, and the most suitable reaction medium wasethanol containing concentrated hydrochloric acid (compared with only ethanol or nosolvent. This study may serve as a guide for the conditions of the reactions to synthesizecompounds having similar chemical structures.

Cavit Kazaz

2007-12-01

340

Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate  

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Full Text Available The reaction of methyl ketones 1a-g with dimethylformamide dimethylacetal (DMFDMA afforded the enaminones 2a-g, which were coupled with diazotized aromatic amines 3a,b to give the corresponding aryl hydrazones 6a-h. Condensation of compounds 6a-h with some aromatic heterocyclic amines afforded iminoarylhydrazones 9a-m. Enaminoazo compounds 12a,b could be obtained from condensation of 6c with secondary amines. The reaction of 6e,h with benzotriazolylacetone yielded 14a,b. Also, the reaction of 6a,b,d-f,h with glycine and hippuric acid in acetic anhydride afforded pyridazinone derivatives 17a-f. Synthesis of pyridazine carboxylic acid derivatives 22a,b from the reaction of 6b,e with dimethyl acetylenedicarboxylate (DMAD in the presence of triphenylphosphine at room temperature is also reported. Most of these reactions were conducted under irradiation in a microwave oven in the absence of solvent in an attempt to improve the product yields and to reduce the reaction times.

Rita M. Borik

2007-08-01

341

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

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Full Text Available 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-(triphenylphosphinepalladium(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 (5fexhibited potent lethal activity against Entamoeba histolytica and Giardia intestinalis with IC50 = 1.47 M/mL, a value lower by a factor of two than that of the standard drug, metronidazole. The boosted activity of 5f was not accompanied by any increased cytotoxicity.The rest of the series also exhibited potent antiparasitic activity with IC50 valuesin the 1.72-4.43 M/mL range. The cytotoxicity of the derivatives 5c and 5e was increased compared to the precursor compound, metronidazole, although they remain non-cytotoxic at concentrations much higher than the antiparasitic concentration of the two derivatives.

Mustafa M. El-Abadelah

2009-07-01

342

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

Science.gov (United States)

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, 1H NMR, 13C 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.

ztrk, Serkan; Y?ld?r?m, Ayhan; etin, Mehmet

2013-01-01

343

para-Functionalized aryl-di-tert-butylfluorosilanes as potential labeling synthons for (18)F radiopharmaceuticals.  

Science.gov (United States)

Broad spectrum: Novel para-functionalized aryl-di-tert-butylfluorosilanes, p-(tBu(2)FSi)C(6)H(4)X (X=functional group), have been made available and broaden the spectrum of silicon-based (18)F acceptors (SiFAs) for potential PET applications. For example, the [(18)F]maleimido derivative 1 has been employed for the synthesis of [(18)F]1- labeled rat serum albumin (RSA), the applicability of which for PET has been verified by in vivo experiments.The syntheses of the functionalized triorganofluorosilanes tBu(2)(p-XC(6)H(4))SiF (3 a, X=SH; 4 a, X=NCS; 4 b, X=NCO; 5, X=NC(4)H(2)O(2); 7, X=COOH; 8 a, X=COONC(4)H(4)O(2); 8 b, X=COOC(6)F(5)) are reported. These compounds display potential as silicon-based fluoride acceptors (SiFAs). The molecular structures of compounds 5, 7, and 8 a have been determined by single-crystal X-ray diffraction studies. With the exception of compounds 8 a and 8 b, all of the compounds could be (18)F-labeled by isotopic exchange in good to high radiochemical yields (RCY) with good to excellent specific activities. As proof of applicability, the maleimido-functionalized SiFA derivative 5, which is specific for thiol groups, has been used for the labeling of rat serum albumin (RSA) that had been derivatized with 2-iminothiolane. The incorporation of [(18)F]5 into the derivatized RSA reached a maximum yield after 30 min at ambient temperature. After purification, the [(18)F]RSA was evaluated in a healthy rat by means of muPET and displayed an expedient in vivo stability over 180 min. PMID:19156812

Iovkova, Ljuba; Wngler, Bjrn; Schirrmacher, Esther; Schirrmacher, Ralf; Quandt, Gabriele; Boening, Guido; Schrmann, Markus; Jurkschat, Klaus

2009-01-01

344

Synthesis and in vitro antifungal activities of new 2-aryl-6,7-methylenedioxy-3,4-dihydroisoquinolin-2-ium bromides.  

Science.gov (United States)

2-Aryl-3,4-dihydroisoquinolin-2-iums might be considered as a class of simple analogues of natural quaternary benzo[c]phenanthridine alkaloids. In this paper, 26 new 2-aryl-6,7-methylenedioxy-3,4-dihydroisoquinolin-2-ium bromides with various substituents in N-aromatic ring were synthesized from commercially available 1,3-benzodioxole in good to excellent yields. All the compounds were elucidated by MS, high resolution (HR)-MS, IR, (1)H- and (13)C-NMR analysis, and evaluated for antifungal activities in vitro against Alternaria alternate, Curvularia lunata and Fusarium oxysporum sp. niveum at 50?g/mL. Most of the compounds showed higher activities against all the test fungi than their natural model compounds sanguinarine and chelerythrine. For A. alternate and Curvularia lunata, most of them were also more active than thiabendazole, a commercial fungicide standard. The structure-activity relationship indicated that the substituent in N-aromatic ring and its position had significant effect on the activity. The general trend was that halogen atoms and CF3 remarkably enhanced the activity while CH3 and OCH3 decreased the activity. Generally, o-substituted isomers were more active than m- and p-substituted isomer. The present results suggest that the title compounds are potential for the development of new isoquinoline antimicrobial agents. PMID:23666271

Yang, Xinjuan; Yao, Yao; Qin, Yuyan; Hou, Zhe; Yang, Rui; Miao, Fang; Zhou, Le

2013-01-01

345

Efficient synthesis of new 1-[Alkyl(aryl)]-5-(3,3,3-trihalo-2-oxopropylidene)pyrrolidine-2-ones  

International Nuclear Information System (INIS)

Reactions of methyl 4-methoxy-6-oxo-7,7,7-trihalo-4-heptenoates 1 and 2 with primary amines RNH2, where R = PhCH2, PhCH2CH2, Ph, 4-MeC6H4, 4-MeOC6H4, 4-ClC6H4, 4-BrC6H4, 2-pyridyl, 5-methyl-3-isoxazolyl, 4-NH2C6H4 affording methyl 4-[alkyl(aryl)amino]-6-oxo-7,7,7- trihalo-4-heptenoates 3, 4, in good yields (57-95%), which suffer quantitative intramolecular cyclocondensation to produce 1-alkyl(aryl)-5-(2-oxo-3,3,3-trihalopropylidene)pyrrolidine-2-ones 5, 6, are reported. The structures of the isolated new products were assigned by means of 1H, 13C NMR measurements and mass spectrometry. The Z and E configuration of compounds 3d and 5b respectively were established from X-ray crystallography. (author)

346

Synthesis, Characterization of Cellulose Grafted N-Oxide Reagent and Its Application in Oxidation of Alkyl/Aryl Halides  

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Full Text Available Oxidation of aliphatic and aromatic halides by N-oxide functionalities supported on 4- vinyl pyridine, (4-VP, grafted cellulose is reported in the present manuscript. Synthesis of graft copolymer of cellulose and poly 4-vinyl pyridine, poly(4-VP, has been carried out using ceric ions as redox initiator. Post-grafting treatment of CellO-g-poly (4-VP with 30% H2O2 in acetic acid gives Cellulose-g-poly (4-VP N-oxide, the polymeric supported oxidizing reagent. The polymeric support, CellO-g-poly (4-VP N-oxide, has been used for oxidation reactions of different alkyl / aryl halide such as 1-bromo-3-methyl butane, 2-bromo propane,1-bromo heptane and benzyl chloride. The polymeric reagent was characterized by IR and thermo-gravimetric analysis. The oxidized products were characterized by FTIR and H1NMR spectral methods. The reagent was reused for the oxidation of a fresh alkyl / aryl halides and it was observed that the polymeric reagent oxidizes the compounds successfully but with little lower product yield.

Poonam K. Dhiman

2011-03-01

347

Aryl ketone synthesis via tandem orthoplatinated triarylphosphite-catalyzed addition reactions of arylboronic acids with aldehydes followed by oxidation.  

Science.gov (United States)

Tandem orthoplatinated triaryl phosphite-catalyzed addition reactions of arylboronic acids with aldehydes followed by oxidation to yield aryl ketones is described. 3-Pentanone was identified as a suitable oxidant for the tandem aryl ketone formation reaction. By using microwave energy, aryl ketones were obtained in high yields with the catalyst loading as low as 0.01%. PMID:20849092

Liao, Yuan-Xi; Hu, Qiao-Sheng

2010-10-15

348

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

349

Copper-mediated cyanation of aryl halide with the combined cyanide source.  

Science.gov (United States)

A simple copper-mediated cyanation of aryl halide with the combination of ammonium bicarbonate and N,N-dimethylformamide as a cyanide source is achieved, providing nitriles in moderate to good yields. This new approach represents an exceedingly practical and safe method for the synthesis of aryl nitriles. PMID:21895018

Zhang, Guoying; Ren, Xinyi; Chen, Jianbin; Hu, Maolin; Cheng, Jiang

2011-10-01

350

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

351

Cu-Catalyzed Arylation of Phenols: Synthesis of Sterically Hindered and Heteroaryl Diaryl Ethers  

OpenAIRE

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 L.

2009-01-01

352

Novel 2-amino-isoflavones exhibit aryl hydrocarbon receptor agonist or antagonist activity in a species/cell-specific context.  

Science.gov (United States)

The aryl hydrocarbon receptor (AhR) mediates the induction of a variety of xenobiotic metabolism genes. Activation of the AhR occurs through binding to a group of structurally diverse compounds, most notably dioxins, which are exogenous ligands. Isoflavones are part of a family which include some well characterised endogenous AhR ligands. This paper analysed a novel family of these compounds, based on the structure of 2-amino-isoflavone. Initially two luciferase-based cell models, mouse H1L6.1c2 and human HG2L6.1c3, were used to identify whether the compounds had AhR agonistic and/or antagonistic properties. This analysis showed that some of the compounds were weak agonists in mouse and antagonists in human. Further analysis of two of the compounds, Chr-13 and Chr-19, was conducted using quantitative real-time PCR in rat H4IIE and human MCF-7 cells. The results indicated that Chr-13 was an agonist in rat but an antagonist in human cells. Chr-19 was shown to be an agonist in rat but more interestingly, a partial agonist in human. Luciferase induction results not only revealed that subtle differences in the structure of the compound could produce species-specific differences in response but also dictated the ability of the compound to be an AhR agonist or antagonist. Substituted 2-amino-isoflavones represent a novel group of AhR ligands that must differentially interact with the AhR ligand binding domain to produce their species-specific agonist or antagonist activity and future ligand binding analysis and docking studies with these compounds may provide insights into the differential mechanisms of action of structurally similar compounds. PMID:22507882

Wall, Richard J; He, Guochun; Denison, Michael S; Congiu, Cenzo; Onnis, Valentina; Fernandes, Alwyn; Bell, David R; Rose, Martin; Rowlands, J Craig; Balboni, Gianfranco; Mellor, Ian R

2012-07-16

353

A New Method for Production of Chiral 2-Aryl-2-fluoropropanoic Acids Using an Effective Kinetic Resolution of Racemic 2-Aryl-2-fluoropropanoic Acids  

Directory of Open Access Journals (Sweden)

Full Text Available We report a new method for the preparation of chiral 2-aryl-2-fluoropropanoic acids, including 2-fluoroibuprofen, a fluorinated analogue of non-steroidal anti-inflammatory drugs (NSAIDs, by the kinetic resolution of racemic 2-aryl-2-fluoropropanoic acids using enantioselective esterification. By applying pivalic anhydride (Piv2O as a coupling agent, bis(?-naphthylmethanol [(?-Np2CHOH] as an achiral alcohol, and (+-benzotetramisole (BTM as a chiral acyl-transfer catalyst, a series of racemic 2-aryl-2-fluoropropanoic acids were kinetically separated to afford the optically active carboxylic acids and the corresponding esters with good to high enantiomeric excesses. This technology can provide a convenient approach to furnish the chiral ?-fluorinated drugs containing quaternary carbons at the ?-positions in the 2-aryl-2-fluoropropanoic acid structure.

Atsushi Tengeiji

2012-06-01

354

Route to benzo- and pyrido-fused 1,2,4-triazinyl radicals via N'-(het)aryl-N'-[2-nitro(het)aryl]hydrazides.  

Science.gov (United States)

A two-step route to 1,3-disubstituted benzo- and pyrido-fused 1,2,4-triazinyl radicals is presented. The route involves the N'-(2-nitroarylation) of easily prepared N'-(het)arylhydrazides via nucleophilic aromatic substitution of 1-halo-2-nitroarenes, which in most cases gives N'-(het)aryl-N'-[2-nitro(het)aryl]hydrazides in good yields. Mild reduction of the nitro group followed by an acid-mediated cyclodehydration gives the fused triazines, which upon alkali treatment afford the desired radicals. Fifteen examples of radicals are presented bearing a range of substituents at N-1, C-3, and C-7, including the pyrid-2-yl and 8-aza analogues. This route to the N'-(het)aryl-N'-[2-nitro(het)aryl]hydrazides, which works well with benzo- and picolinohydrazides, required a modification for aceto- and trifluoroacetohydrazides that involved a multistep synthesis of asymmetrically 1,1-diaryl-substituted hydrazines. PMID:24350615

Berezin, Andrey A; Zissimou, Georgia; Constantinides, Christos P; Beldjoudi, Yassine; Rawson, Jeremy M; Koutentis, Panayiotis A

2014-01-01

355

Synthesis and Biological Activity of 3-(2-Furanyl-6-Aryl-1,2,4-Triazolo[3,4-b]-1,3,4 –Thiadiazoles  

Directory of Open Access Journals (Sweden)

Full Text Available 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 promoting effects on mung bean radicles.

Zi-Yi Zhang

2002-08-01

356

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.

2013-08-01

357

Synthesis of N-Substituted Derivatives of N-(4-(N- (5-Chloro-2 methoxyphenyl)sulfamoyl)phenyl)acetamide with potential antiurease activity  

International Nuclear Information System (INIS)

In this study, a new series of N-alkyl/arakyl derivatives of N-(4-(N-(5-chloro-2-methoxyphenyl)sulfamoyl)phenyl)acetamide (5a-k) was synthesized and screened for enzyme inhibition activity. Target compounds, N-alkyl/arakyl sulfamoylacetamides (5a-k) were synthesized by stirring N-(4-(N-(5-chloro-2-methoxyphenyl)sulfamoyl)phenyl)acetamide (3) with different electrophiles (4a-k) in the presence of sodium hydride (NaH) and N, N-dimethylformamide (DMF). The structures of all the synthesized compounds have been deduced from their spectral (1H-NMR, IR, EI-MS) data. All the new compounds displayed antiurease activity to varying degree. (author)

358

Systematic investigations on the reduction of 4-aryl-4-oxoesters to 1-aryl-1,4-butanediols with methanolic sodium borohydride  

Directory of Open Access Journals (Sweden)

Full Text Available 4-Aryl-4-oxoesters undergo facile reduction of both the keto and the ester groups with methanolic NaBH4 at room temperature to yield the corresponding 1-aryl-1,4-butanediols whereas 4-alkyl-4-oxoesters furnish the corresponding 1,4-butanolides via selective reduction of the keto moiety. Results of a detailed and systematic investigation of the reaction are described.

Subrata Kumar Chaudhuri

2010-09-01

359

Functionalization of heterocyclic compounds using polyfunctional magnesium and zinc reagents  

Directory of Open Access Journals (Sweden)

Full Text Available In this review we summarize the most important procedures for the preparation of functionalized organzinc and organomagnesium reagents. In addition, new methods for the preparation of polyfunctional aryl- and heteroaryl zinc- and magnesium compounds, as well as new Pd-catalyzed cross-coupling reactions, are reported herein. Experimental details are given for the most important reactions in the Supporting Information of this article.

Paul Knochel

2011-09-01

360

Functionalization of heterocyclic compounds using polyfunctional magnesium and zinc reagents.  

Science.gov (United States)

In this review we summarize the most important procedures for the preparation of functionalized organzinc and organomagnesium reagents. In addition, new methods for the preparation of polyfunctional aryl- and heteroaryl zinc- and magnesium compounds, as well as new Pd-catalyzed cross-coupling reactions, are reported herein. Experimental details are given for the most important reactions in the Supporting Information File 1 of this article. PMID:21977211

Knochel, Paul; Schade, Matthias A; Bernhardt, Sebastian; Manolikakes, Georg; Metzger, Albrecht; Piller, Fabian M; Rohbogner, Christoph J; Mosrin, Marc

2011-01-01

361

Unusual aryl-porphyrin rotational barriers in peripherally crowded porphyrins.  

Science.gov (United States)

Previous studies of 5,10,15,20-tetraarylporphyrins have shown that the barrier for meso aryl-porphyrin rotation (DeltaG++(ROT)) varies as a function of the core substituent M and is lower for a small metal (M = Ni) compared to a large metal (M = Zn) and for a dication (M = 4H(2+)) versus a free base porphyrin (M = 2H). This has been attributed to changes in the nonplanar distortion of the porphyrin ring and the deformability of the macrocycle caused by the core substituent. In the present work, X-ray crystallography, molecular mechanics (MM) calculations, and variable temperature (VT) (1)H NMR spectroscopy are used to examine the relationship between the aryl-porphyrin rotational barrier and the core substituent M in some novel 2,3,5,7,8,10,12,13,15,17,18,20-dodecaarylporphyrins (DArPs), and specifically in some 5,10,15,20-tetraaryl-2,3,7,8,12,13,17,18-octaphenylporphyrins (TArOPPs), where steric crowding of the peripheral groups always results in a very nonplanar macrocycle. X-ray structures of DArPs indicate differences in the nonplanar conformation of the macrocycle as a function of M, with saddle conformations being observed for M = Zn, 2H or M = 4H(2+) and saddle and/or ruffle conformations for M = Ni. VT NMR studies show that the effect of protonation in the TArOPPs is to increase DeltaG++(ROT), which is the opposite of the effect seen for the TArPs, and MM calculations also predict a strikingly high barrier for the TArOPPs when M = 4H(2+). These and other findings suggest that the aryl-porphyrin rotational barriers in the DArPs are closely linked to the deformability of the macrocycle along a nonplanar distortion mode which moves the substituent being rotated out of the porphyrin plane. PMID:12665356

Medforth, Craig J; Haddad, Raid E; Muzzi, Cinzia M; Dooley, Neal R; Jaquinod, Laurent; Shyr, David C; Nurco, Daniel J; Olmstead, Marilyn M; Smith, Kevin M; Ma, Jian-Guo; Shelnutt, John A

2003-04-01

362

Cyprodinil as an activator of aryl hydrocarbon receptor  

International Nuclear Information System (INIS)

Highlights: ? Cyprodinil activated the aryl hydrocarbon receptor (AHR). ? Cyprodinil induced nuclear translocation of the AHR, and the expression of CYP1A1. ? Cyprodinil enhanced dexamethasone-induced gene expression. ? Cyprodinil phosphorylated ERK, indicating its deregulation of ERK activity. -- Abstract: Cyprodinil is a pyrimidinamine fungicide, used worldwide by agriculture. It is used to protect fruit plants and vegetables from a wide range of pathogens. Benzo[a]pyrene (BaP) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are toxic environmental pollutants and are prototypes of aryl hydrocarbon receptor (AHR) ligands. Although the structure of cyprodinil distinctly differs from those of BaP and TCDD, our results show that cyprodinil induced nuclear translocation of the AHR, and induced the transcriptional activity of aryl hydrocarbon response element (AHRE). Cyprodinil induced the expression of cytochrome P450 (CYP) 1A1, a well-known AHR-targeted gene, in ovarian granulosa cells, HO23, and hepatoma cells, Hepa-1c1c7. Its induction did not appear in AHR signal-deficient cells, and was blocked by the AHR antagonist, CH-223191. Cyprodinil decreased AHR expression in HO23 cells, resulting in CYP1A1 expression decreasing after it peaked at 9 h of treatment in HO23 cells. Dexamethasone is a synthetic agonist of glucocorticoids. Cyprodinil enhanced dexamethasone-induced gene expression, and conversely, its induction of CYP1A1 expression was decreased by dexamethasone in HO23 cells, indicating its induction of crosstalk between the AHR and glucocorticoid receptor and its role as a potential endocrine disrupter. In addition to BaP, TCDD, and an AHR agonist, ?-NF, cyprodinil also phosphorylated extracellular signal-regulated kinase (ERK) in HO23 and Hepa-1c1c7 cells, indicating its deregulation of ERK activity. In summary, our results demonstrate that cyprodinil, similar to BaP, acts as an AHR activator, a potential endocrine disrupter, and an ERK disrupter

363

Organoantimony(III) compounds containing (imino)aryl ligands of the type 2-(RN=CH)C6H4 (R = 2',4',6'-Me3C6H2, 2',6'-(i)Pr2C6H3): bromides and chalcogenides.  

Science.gov (United States)

The reaction of 2-(RN=CH)C(6)H(4)MgBr [R = 2',4',6'-Me(3)C(6)H(2) (R(1)), 2',6'-(i)Pr(2)C(6)H(3) (R(2))] [prepared from 2-(R(1)N=CH)C(6)H(4)Br (1) or 2-(R(2)N=CH)C(6)H(4)Br (2) and Mg] with SbCl(3) in a 2 : 1 and 1 : 1 molar ratio followed by treatment with an aqueous KBr solution gave [2-(R(1)N=CH)C(6)H(4)](2)SbBr (3) and [2-(R(2)N=CH)C(6)H(4)](2)SbBr (4) as well as [2-(R(1)N=CH)C(6)H(4)]SbBr(2) (6) and [2-(R(2)N=CH)C(6)H(4)]SbBr(2) (7). Treatment of 4 with Na(2)S9H(2)O provided the dinuclear [{2-(R(2)N=CH)C(6)H(4)}(2)Sb](2)S (5). Heterocyclic species, i.e. the oxide cyclo-[{2-(R(2)N=CH)C(6)H(4)}SbO](3) (8) and the sulfides cyclo-[{2-(R(1)N=CH)C(6)H(4)}SbS](2) (9) and cyclo-[{2-(R(2)N=CH)C(6)H(4)}SbS](2) (10), were obtained by reacting dibromides 6 and 7 with KOH and Na(2)S9H(2)O, respectively, in a water-toluene solvent mixture. The sulfide 10 reacted with [W(CO)(5)(thf)] to yield the heterometallic complex cyclo-[{2-(R(2)N=CH)C(6)H(4)}SbS](2)[W(CO)(5)] (11). The compounds were characterised by multinuclear NMR spectroscopy in solution, mass spectrometry and IR spectroscopy in the solid state. The molecular structures of 4, 5, 6CHCl(3), 7, 9CH(2)Cl(2), 10 and 110.25CH(3)OH were established by single-crystal X-ray diffraction. Theoretical calculations using DFT methods were carried out on bromide 7 and the geometrical isomers of its dimer association as well as the geometrical isomers of sulfide 10 and its monomer. PMID:23184021

Preda, Ana Maria; Ra?, Ciprian I; Silvestru, Cristian; Breunig, Hans J; Lang, Heinrich; Rffer, Tobias; Mehring, Michael

2013-01-28

364

Palladium(II)-Catalyzed Regioselective Ortho Arylation of sp(2) C-H Bonds of N-Aryl-2-amino Pyridine Derivatives.  

Science.gov (United States)

The direct arylation of N-(2-pyridyl) substituted anilines is described. Arylation takes place in ortho position to the amine functionality and is directed by the pyridine N-substituent. Remarkably, N-arylation was never observed as a competing process even though conditions also suitable for Buchwald-Hartwig reactions were applied. The scope of the reaction was investigated in terms of aryl donors as well as the electronic nature of the substrate. Good yields were obtained for most examples through an operationally simple procedure, which did not require inert conditions or even glove box techniques. Pd(OAc)(2) was applied as a cheap catalyst and boronic acids as readily available aryl donors. To obtain full conversion, 1,4-benzoquinone and a silver salt (e.g., Ag(2)O) were required as additives and reacted at relatively mild temperatures (e.g., 80 C). Additionally, the pyridine-directing group was cleaved after the reaction to give ortho-arylated aniline derivatives. PMID:23136619

Koley, Moumita; Dastbaravardeh, Navid; Schnrch, Michael; Mihovilovic, Marko D

2012-09-01

365

Catalytic arylation methods from the academic lab to industrial processes  

CERN Document Server

A current view of the challenging field of catalytic arylation reactions. Clearly structured, the chapters in this one-stop resource are arranged according to the reaction type, and focus on novel, efficient and sustainable processes, rather than the well-known and established cross-coupling methods.The entire contents are written by two authors with academic and industrial expertise to ensure consistent coverage of the latest developments in the field, as well as industrial applications, such as C-H activation, iron and gold-catalyzed coupling reactions, cycloadditions or novel methodologies

Burke, Anthony J

2014-01-01

366

Synthesis of quinoxaline derivatives via condensation of aryl-1,2-diamines with 1,2-diketones using (NH4)6 Mo7 O24 . 4 H2 O as an efficient, mild and reusable catalyst  

International Nuclear Information System (INIS)

Ammonium heptamolybdate tetrahydrate [(NH4)6Mo7O24.4H2O] efficiently catalyzes the condensation of aryl-1,2-diamines with l,2-diketones in EtOH/H2O as a green media at room temperature to afford quinoxaline derivatives as biologically interesting compounds. Ease of recycling of the catalyst is one of the most advantages of the proposed method

367

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  

OpenAIRE

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

368

2D-QSPR/DFT studies of aryl-substituted PNP-Cr-based catalyst systems for highly selective ethylene oligomerization.  

Science.gov (United States)

1-Hexene and 1-octene are important comonomers for the synthesis of high performance polyolefins. Recently, various N-substituted Cr-bis(diphenylphosphino)amine (PNP-Cr) catalysts show the potential as excellent candidates for highly selective ethylene trimerization/tetramerization. In this work, a series of aryl-substituted PNP-Cr catalysts were studied by two-dimensional quantitative structure-property relationship (QSPR) method based on density functional theory (DFT) calculations. The heuristic method (HM) and best multi-linear regression (BMLR) were used to establish the best linear regression models to describe the relationship between selectivities and catalyst structures. Both Cr(I) and Cr(II) active site models for ethylene trimerization/tetramerization were considered. It was found that 1) the relativity and stability of the models were increased by using self-defined descriptors based on DFT calculations; 2) Cr(I)/Cr(III) centers were the most plausible active sites for ethylene trimerization, while Cr(II)/Cr(IV) active sites were most possibly responsible for ethylene tetramerization; and 3) the skeleton structures of the PNP-Cr system with good complanation and symmetry were crucial for achieving excellent catalytic selectivity of 1-octene, while the PNP-Cr backbone with a large steric effect on N atom would benefit ethylene trimerization. Six new PNP ligands with high selectivity toward ethylene trimerization/tetramerization were predicted based on descriptor analysis and the best linear regression models providing a good basis for further development of novel catalyst systems with better performance. PMID:24554126

Tang, Siyang; Liu, Zhen; Zhan, Xingwen; Cheng, Ruihua; He, Xuelian; Liu, Boping

2014-03-01

369

Pharmacological characterization of the vascular effects of aryl isothiocyanates: is hydrogen sulfide the real player?  

Science.gov (United States)

Hydrogen sulfide (H?S) is an endogenous gasotransmitter, which mediates important physiological effects in the cardiovascular system. Accordingly, an impaired production of endogenous H?S contributes to the pathogenesis of important cardiovascular disorders, such as hypertension. Therefore, exogenous compounds, acting as H?S-releasing agents, are viewed as promising pharmacotherapeutic agents for cardiovascular diseases. Thus, this paper aimed at evaluating the H?S-releasing properties of some aryl isothiocyanate derivatives and their vascular effects. The release of H?S was determined by amperometry, spectrophotometry and gas/mass chromatography. Moreover, the vascular activity of selected isothiocyanates were tested in rat conductance (aorta) and coronary arteries. Since H?S has been recently reported to act as an activator of vascular Kv7 potassium channels, the possible membrane hyperpolarizing effects of isothiocyanates were tested on human vascular smooth muscle (VSM) cells by spectrofluorescent dyes. Among the tested compounds, phenyl isothiocyanate (PhNCS) and 4-carboxyphenyl isothiocyanate (PhNCS-COOH) exhibited slow-H?S-release, triggered by organic thiols such as L-cysteine. These compounds were endowed with vasorelaxing effects on conductance and coronary arteries. Moreover, these two isothiocyanates caused membrane hyperpolarization of VSM cells. The vascular effects of isothiocyanates were strongly abolished by the selective Kv7-blocker XE991. In conclusion, the isothiocyanate function can be viewed as a suitable slow H?S-releasing moiety, endowed with vasorelaxing and hypotensive effects, typical of this gasotransmitter. Thus, such a chemical moiety can be employed for the development of novel chemical tools for basic studies and promising cardiovascular drugs. PMID:24287004

Martelli, Alma; Testai, Lara; Citi, Valentina; Marino, Alice; Bellagambi, Francesca G; Ghimenti, Silvia; Breschi, Maria C; Calderone, Vincenzo

2014-01-01

370

Biaryl Synthesis by Ring-Opening Friedel-Crafts Arylation of 1,4-Epoxy-1,4-dihydronaphthalenes Catalyzed by Iron Trichloride.  

Science.gov (United States)

Biaryl and heterobiaryl compounds are important frameworks across a range of fields including pharmaceutical and functional material chemistries. We have accomplished the efficient synthesis of various naphthalene-linked arenes and heteroarenes as biaryls and heterobiaryls by the FeCl3 -catalyzed Friedel-Crafts reactions accompanied by the ring-opening of the 1,4-epoxy moiety of 1,4-epoxy-1,4-dihydronaphthalenes. Especially, it is noteworthy that 1-silylated substrates were regioselectively transformed to the 3-aryl-1-silylnaphthalenes and the double Friedel-Crafts reactions using thiophene derivatives could directly produce the corresponding bis-naphthlated thiophene derivatives. PMID:25469749

Sawama, Yoshinari; Asai, Shota; Kawajiri, Takahiro; Monguchi, Yasunari; Sajiki, Hironao

2015-01-26

371

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 ω-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

372

Synthesis, characterization and antibacterial activity of some 5-aryl-1, 3-Diphenyl 1-4, 5-dihydro-1H-Pyrazoles  

International Nuclear Information System (INIS)

The condensation of acetophenone (I) with arylaldehyde (II) was investigated and the resulting chalcones 2-Arylidene 1-Acetophenone (III) were reacted with phenyl hydrazine and acetic acid to produce substituted 5-aryl-1, 3-diphenyl-4, 5-dihydro-1H-Pyrazoles (IV). The structures of all products were studied by H-NMR, IR, thermal and elemental analysis. Thermo-gravimetric (TG) and differential thermal analysis (DTA) was applied to investigate the thermal behavior and structure of the synthesized compounds. 2-Pyrazolines (IV) exhibited moderate activity against Streptococcus faecalis ATCC 19433, Klebsiella pneumoniae ATCC 13883, Proteus vulgaris ATCC 25922, Shigella sonnei ATCC 25931 and Peseudom oaeruginosa ATCC 27853. (author)

373

Direct palladium-catalyzed C-4 arylation of tri-substituted furans with aryl chlorides: An efficient access to heteroaromatics  

International Nuclear Information System (INIS)

A series of functionalized furans were synthesized by way of a palladium -catalyzed coupling reaction of 2,3,5-tri substituted furans with aryl chlorides through C-H bond cleavages at C-4 position. The feature of the reaction was facilitative preparation of furan derivatives with good functional group tolerance. All reactions gave the desired products in moderate to good yields in the presences of BuAd2P and t-BuOK in DMF at 120 .deg. C after 15 h

374

Synthesis of alkyl- and aryl-amino-substituted anthraquinone derivatives by microwave-assisted copper(0)-catalyzed Ullmann coupling reactions.  

Science.gov (United States)

This protocol describes the efficient, generally applicable Ullmann coupling reaction of bromaminic acid with alkyl- or aryl-amines in phosphate buffer under microwave irradiation using elemental copper as a catalyst. The reaction leads to a number of biologically active compounds. As a prototypical example, the synthesis of a new, potent antagonist of human platelet P2Y(12) receptors, which has potential as an antithrombotic drug, is described in detail. The optimized protocol includes a description of an appropriate reaction setup, thin layer chromatography for monitoring the reaction and a procedure for the isolation, purification and characterization of the anticipated product. The reaction is performed without the use of a glove box and there is no requirement for an inert atmosphere. The reaction typically proceeds within 2-30 min, the protocol, including workup, generally takes 1-3 h to complete. PMID:20431540

Baqi, Younis; Mller, Christa E

2010-05-01

375

Synthesis and structure-active relationship of 1-aryl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline anticonvulsants.  

Science.gov (United States)

We have previously disclosed that some 6,7-dimethoxyisoquinoline derivatives are able to produce anticonvulsant effects in different animal models of epilepsy. Following these studies this paper describes the synthesis of a small series of new 1-aryl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines strictly related to previously reported analogues. This novel series of isoquinolines was designed on the basis of well defined structure-active relationship (SAR) information already acquired for this class of anticonvulsant agents. The pharmacological effects of the new synthesized compounds were evaluated against audiogenic seizures in Dilute Brown non-Agouti (DBA/2) mice. The preliminary pharmacological screening led to the identification of a new active molecule the 2-acetyl-1-(4'-methylphenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (6d) that displayed significant anticonvulsant activity. Computational studies helped to rationalize these obtained pharmacological results. PMID:21139262

Gitto, Rosaria; De Luca, Laura; Ferro, Stefania; Agnello, Stefano; Russo, Emilio; De Sarro, Giovanbattista; Chimirri, Alba

2010-12-01

376

Silicon dioxide surfaces with aryl interaction sites for chromatographic applications  

International Nuclear Information System (INIS)

The paper presents the results of a study on aryl phases aimed at the increase of the separation selectivity of substances containing ? electrons, and improving the reproducibility of retention data. The above phases contain not only a carbon chain of a different length, linking them to the support, but also one or two aromatic rings. The suitability of the newly obtained packings for the purposes of high-performance liquid chromatography was verified on the basis of a description of surface topography before and after the modification process. Various physicochemical methods were employed to determine the effectiveness of chemical modification, i.e., elemental analysis, infrared spectroscopy, and nuclear magnetic resonance. The aryl packings obtained were used for the separation of polynuclear aromatic hydrocarbons and budesonide epimers, tested under hydroorganic conditions (water/ethanol, water/methanol, water/acetonitrile). The application of a methanol/water mobile phase and a new-generation naphthylpropyl stationary phase for the separation of the 22R and 22S diastereoisomers of budesonide allowed the obtention of reproducible results and make qualitative and quantitative determinations of particular enantiomers

377

Synthesis of 17beta-N-substituted 19-Nor-10-azasteroids as inhibitors of human 5alpha-reductases I and II.  

Science.gov (United States)

The synthesis of 17beta-[N-(phenyl)methyl/phenyl-amido] substituted 10-azasteroids has been accomplished by either the TiCl4- or TMSOTf-catalysed reaction of carbamates 11 and 12 with Danishefsky's diene. The reaction provided 5alpha-H isomers 3a-5a and 5beta-H isomers 3b-5b depending on the reaction conditions. Both epimers of each compound were tested against human 5alpha-reductase types I and II. Unexpectedly, 5beta-H compounds were found more active than their 5alpha-H counterparts, the best inhibitors being 3b (IC50=279 and 2000 nM toward isoenzyme I and II, respectively) and 5b (IC50=913 and 247 nM toward isoenzymes I and II, respectively). PMID:12213459

Scarpi, Dina; Occhiato, Ernesto G; Danza, Giovanna; Serio, Mario; Guarna, Antonio

2002-11-01

378

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

379

A traceless aryl-triazene linker for DNA-directed chemistry.  

Science.gov (United States)

DNA-directed synthesis of encoded combinatorial libraries of small organic compounds most often involves transfer of organic building blocks from one DNA strand to another. This requires cleavable linkers to enable cleavage of the link to the original DNA strand from which the building block is transferred. Relatively few cleavable linkers are available for DNA-directed synthesis and most often they leave an amino group at the organic molecule. Here we have extended the application of aryltriazenes as traceless linkers for DNA-directed synthesis. After reaction of one building block with a building block at another DNA strand the triazene linker is cleaved and reduced with hypophosphorous acid in high yield to leave the aryl group with a hydrogen in place of the triazene i.e. without a functional group trace. It was also demonstrated that alternatively the triazene could be converted to an azide, which was used in a cycloaddition reaction. The linker is generally stable at pH > 7 and could be stored for several months in a freezer without significant degradation. PMID:23443893

Hejesen, Christian; Petersen, Lars K; Hansen, Nils Jakob V; Gothelf, Kurt V

2013-04-21

380

Interaction of fish aryl hydrocarbon receptor paralogs (AHR1 and AHR2) with the retinoblastoma protein  

Energy Technology Data Exchange (ETDEWEB)

The aryl hydrocarbon receptor (AHR) mediates the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. In some mammalian cell lines, TCDD induces G1 cell cycle arrest, which depends on an interaction between the AHR and the retinoblastoma tumor suppressor (RB). Mammals possess one AHR, whereas fishes possess two or more AHR paralogs that differ in the domains important for AHR-RB interactions in mammals. To test the hypothesis that fish AHR paralogs differ in their ability to interact with RB, we cloned RB cDNA from Atlantic killifish, Fundulus heteroclitus, and studied the interactions of killifish RB protein with killifish AHR1 and AHR2. In coimmunoprecipitation experiments, in vitro-expressed killifish RB coprecipitated with both AHR1 and AHR2. Consistent with these results, both killifish AHR1 and AHR2 interacted with RB in mammalian two-hybrid assays. These results suggest that both fish AHR1 and AHR2 paralogs may have the potential to influence cell proliferation through interactions with RB.

Merson, Rebeka R., E-mail: rmerson@ric.edu [Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 (United States); Biology Department, Rhode Island College, 500 Mt. Pleasant Ave., Providence, RI 02908 (United States); Karchner, Sibel I.; Hahn, Mark E. [Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 (United States)

2009-08-13

381

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

382

Regulation of Aryl Hydrocarbon Receptor Function by Selective Estrogen Receptor Modulators  

Science.gov (United States)

Selective estrogen receptor modulators (SERMs), such as tamoxifen (TAM), have been used extensively for the treatment and prevention of breast cancer and other pathologies associated with aberrant estrogen receptor (ER) signaling. These compounds exhibit cell-selective agonist/antagonist activities as a consequence of their ability to induce different conformational changes in ER, thereby enabling it to recruit functionally distinct transcriptional coregulators. However, the observation that SERMs can also regulate aspects of calcium signaling and apoptosis in an ER-independent manner in some systems suggests that some of the activity of drugs within this class may also arise as a consequence of their ability to interact with targets other than ER. In this study, we demonstrate that 4-hydroxy-TAM (4OHT), an active metabolite of TAM, directly binds to and modulates the transcriptional activity of the aryl hydrocarbon receptor (AHR). Of specific interest was the observation, that in the absence of ER, 4OHT can induce the expression of AHR target genes involved in estradiol metabolism, cellular proliferation, and metastasis in cellular models of breast cancer. The potential role for AHR in SERM pharmacology was further underscored by the ability of 4OHT to suppress osteoclast differentiation in vitro in part through AHR. Cumulatively, these findings provide evidence that it is necessary to reevaluate the relative roles of ER and AHR in manifesting the pharmacological actions and therapeutic efficacy of TAM and other SERMs. PMID:19901195

DuSell, Carolyn D.; Nelson, Erik R.; Wittmann, Bryan M.; Fretz, Jackie A.; Kazmin, Dmitri; Thomas, Russell S.; Pike, J. Wesley; McDonnell, Donald P.

2010-01-01

383

Cigarette smoke condensate induces aryl hydrocarbon receptor-dependent changes in gene expression in spermatocytes.  

Science.gov (United States)

Cigarette smoke contains numerous compounds that cause oxidative stress and alter gene expression in many tissues, and cigarette smoking is correlated with male infertility. To identify mechanisms by which this occurs, we evaluated expression of antioxidant genes in mouse spermatocytes in response to cigarette smoke condensate (CSC). CSC exposure led to oxidative stress and dose-dependent up-regulation of Hsp90aa1, Ahr, Arnt, Sod1, Sod2, and Cyp1a1 expression in a mouse spermatocyte cell line. An antagonist of the aryl hydrocarbon receptor (AHR) abrogated several CSC-mediated changes in mRNA and protein levels. Consistent with these results, spermatocytes isolated by laser-capture microdissection from CSC-treated mice showed increased expression of several antioxidant genes. In vivo exposure to CSC was genotoxic to spermatocytes, resulting in apoptosis and disruptions to the seminiferous tubules. Our in vivo and in vitro data indicate that CSC-mediated damage to murine spermatocytes is AHR-dependent and is mediated by oxidative stress. PMID:23069111

Esakky, Prabagaran; Hansen, Deborah A; Drury, Andrea M; Moley, Kelle H

2012-12-01

384

Novel fluorescent 1,8-naphthalimide derivatives containing thiophene and pyrazole moieties: Synthesis by direct C-H arylation and evaluation of photophysical and electrochemical properties  

Science.gov (United States)

A series of novel 1,8-naphthalimide derivatives containing thiophene and pyrazole moities were synthesized by direct Pd-catalyzed C-H arylation and then characterized by 1H NMR, 13C NMR, MALDI-HRMS, and elementary analysis. The photophysical and electrochemical properties of the derivatives were also investigated. All compounds have green emission both in diluted CH2Cl2 solution and solid film. The cyclic voltammetry (CV) measurements showed that the target compounds had a lowest unoccupied molecular orbital (LUMO) range from -3.49 eV to -3.29 eV and a highest occupied molecular orbital (HOMO) range from -6.04 eV to -5.81 eV. Quantum chemical calculations were performed to obtain the optimized ground-state geometry as well as the spatial distributions of the HOMO, LUMO levels of the compounds.

Jin, Zhengneng; Wu, Jiashou; Wang, Chuanfeng; Dai, Guoliang; Liu, Shiyong; Lu, Jianmei; Jiang, Huajiang

2014-01-01

385

Mechanism of arylating quinone toxicity involving Michael adduct formation and induction of endoplasmic reticulum stress.  

Science.gov (United States)

Quinones permeate our biotic environment, contributing to both homeostasis and cytotoxicity. All quinones generate reactive oxygen species through redox cycling, while partially substituted quinones also undergo arylation (Michael adduct formation) yielding covalent bonds with nucleophiles such as cysteinyl thiols. In contrast to reactive oxygen species, the role of arylation in quinone cytotoxicity is not well understood. We found that the arylating quinones, including unsubstituted 1,4-benzoquinone (1,4-BzQ) and partially substituted vitamin E congener gamma-tocopherol quinone (gamma-TQ), were cytotoxic, with gamma-TQ > 1,4-BzQ, whereas the fully substituted nonarylating vitamin E congener alpha-tocopherol quinone was not. In vitro, both arylating quinones formed Michael adducts with the thiol nucleophile N-acetylcysteine (NAC) at rates where 1,4-BzQ > gamma-TQ. In cultured cells, concurrent addition of NAC eliminated 1,4-BzQ caused toxicity, but preincubation was required for the same NAC detoxification effect on gamma-TQ. These data clearly established the role of arylation in quinone toxicity and revealed that arylating quinone structure affects cytotoxicity by governing detoxification through the rate of adduct formation. Furthermore, arylating quinones induced endoplasmic reticulum (ER) stress by activating the pancreatic ER kinase (PERK) signaling pathway including elF2alpha, ATF4, and C/EBP homologous protein (CHOP). Detoxification by NAC greatly attenuates CHOP induction in arylating quinone-treated cells, suggesting that ER stress is a cellular mechanism for arylating quinone cytotoxicity. PMID:16505371

Wang, Xinhe; Thomas, Beena; Sachdeva, Rakesh; Arterburn, Linnea; Frye, Lucy; Hatcher, Patrick G; Cornwell, David G; Ma, Jiyan

2006-03-01

386

Molecular polarizability of organic molecules and their complexes. Communication LIV. Molar volumes of polyaryl organoelement compounds in solutions, extrapolated to infinite dilution, and steric structure of the molecules  

International Nuclear Information System (INIS)

Molar volumes in various solvents were determined for organic derivatives of silicon, phosphorus, arsenic, sulfur, and tellurium, containing aryl nuclei capable to internal rotation about single bonds between them and bridging groups. Additive analysis of the molar volumes of these compounds showed that the aryl nuclei are acoplanar with respect to the bridging groups. Most probable is a conrotatory mutual orientation of the aromatic rings. Molar volumes were also determined for a series of compounds with two bridging groups, which can serve as models of an extreme case of mutual proximity of aryl ring planes in diaryl systems with one bridging group. A possibility for considerably simplifying the methods for determination of dipole moments and Kerr constants for compounds whose molar volumes can be calculated by our developed additive scheme is demonstrated

387

Mild Palladium-Catalyzed Cyanation of (Hetero)aryl Halides and Triflates in Aqueous Media.  

Science.gov (United States)

A mild, efficient, and low-temperature palladium-catalyzed cyanation of (hetero)aryl halides and triflates is reported. Previous palladium-catalyzed cyanations of (hetero)aryl halides have required higher temperatures to achieve good catalytic activity. This current reaction allows the cyanation of a general scope of (hetero)aryl halides and triflates at 2-5 mol % catalyst loadings with temperatures ranging from rt to 40 C. This mild method was applied to the synthesis of lersivirine, a reverse transcriptase inhibitor. PMID:25555140

Cohen, Daniel T; Buchwald, Stephen L

2015-01-16

388

Frontispiece: Palladium-Catalyzed ?-Arylation of Arylketones at Low Catalyst Loadings.  

Science.gov (United States)

?-Arylation of Arylketones The recently reported [Pd(IHept)(acac)Cl] complex has been found to be an outstanding catalyst for the ?-arylation of ketones. In their Communication on page?17272?ff., S. Nolan et?al. report a meticulous optimization of the reaction conditions that allows this reaction to proceed with high selectivity towards mono-arylation products for a broad scope of functionalized and challenging substrates. The protocol was also suitable for the synthesis of a pharmaceutically relevant intermediate using a much lower catalyst loading compared with previously reported methodologies. PMID:25515635

Marelli, Enrico; Corpet, Martin; Davies, Sian R; Nolan, Steven P

2014-12-22

389

Ni-Catalyzed ?-arylation of esters and amides with phenol derivatives.  

Science.gov (United States)

A nickel-catalyzed ?-arylation of esters and amides with phenol derivatives has been accomplished. In the presence of our unique nickel catalyst, prepared in situ from Ni(cod)2, 3,4-bis(dicyclohexylphosphino)thiophene (dcypt), and K3PO4, various esters and amides undergo ?-arylation with O-arylpivalates or O-arylcarbamates to afford the corresponding coupling products. The thus obtained ?-aryl esters and amides are useful precursors of privileged motifs such as ?-arylcarboxylic acids and ?-arylamines. PMID:25429373

Koch, Eva; Takise, Ryosuke; Studer, Armido; Yamaguchi, Junichiro; Itami, Kenichiro

2015-01-18

390

Synthesis of 3-substituted and 2,3-disubstituted quinazolinones via Cu-catalyzed aryl amidation.  

Science.gov (United States)

CuI/4-hydroxy-L-proline catalyzed coupling of N-substituted o-bromobenzamides with formamide takes place at 80 C, affording 3-substituted quinazolinones directly. Under these conditions other amides that were tested only provided simple coupling products, which can be converted into 2,3-disubstituted quinazolinones via HMDS/ZnCl(2) mediated condensative cyclization. PMID:22313025

Xu, Lanting; Jiang, Yongwen; Ma, Dawei

2012-02-17

391

Unusual aryl-porphyrin rotational barriers in peripherally crowded porphyrins.  

Energy Technology Data Exchange (ETDEWEB)

Previous studies of 5,10,15,20-tetraarylporphyrins have shown that the barrier for meso aryl-porphyrin rotation ({Delta}G{sub ROT}) varies as a function of the core substituent M and is lower for a small metal (M = Ni) compared to a large metal (M = Zn) and for a dication (M 4H{sup 2+}) versus a free base porphyrin (M = 2H). This has been attributed to changes in the nonplanar distortion of the porphyrin ring and the deformability of the macrocycle caused by the core substituent. In the present work, X-ray crystallography, molecular mechanics (MM) calculations, and variable temperature (VT) {sup 1}H NMR spectroscopy are used to examine the relationship between the aryl-porphyrin rotational barrier and the core substituent M in some novel 2,3,5,7,8,10,12,13,15,17,18,20-dodecaarylporphyrins (DArPs), and specifically in some 5,10,15,20-tetraaryl-2,3,7,8,12,13,17,18-octaphenylporphyrins (TArOPPs), where steric crowding of the peripheral groups always results in a very nonplanar macrocycle. X-ray structures of DArPs indicate differences in the nonplanar conformation of the macrocycle as a function of M, with saddle conformations being observed for M = Zn, 2H or M = 4H{sup 2+} and saddle and/or ruffle conformations for M = Ni. VT NMR studies show that the effect of protonation in the TArOPPs is to increase {Delta}G{sub ROT}, which is the opposite of the effect seen for the TArPs, and MM calculations also predict a strikingly high barrier for the TArOPPs when M = 4H{sup 2+}. These and other findings suggest that the aryl-porphyrin rotational barriers in the DArPs are closely linked to the deformability of the macrocycle along a nonplanar distortion mode which moves the substituent being rotated out of the porphyrin plane.

Shyr, David C. (University of California, Davis, CA); Dooley, Neal R. (University of California, Davis, CA); Haddad, Raid Edward (University of New Mexico, Albuquerque, NM); Shelnutt, John Allen; Muzzi, Cinzia M. (University of California, Davis, CA); Ma, Jian-Guo (University of New Mexico, Albuquerque, NM); Olmstead, Marilyn M. (University of California, Davis, CA); Jaquinod, Laurent A. (University of California, Davis, CA); Nurco, Daniel J. (University of California, Davis, CA); Medforth, Craig John; Smith, Kevin M. (Louisiana State University, Baton Rouge, LA)

2003-06-01

392

HPLC analysis of commercial alkyl and aryl quaternary ammonium compounds used in organoclay type rheological additives.  

Science.gov (United States)

Mixtures of aliphatic and aromatic "quats" can be qualitatively identified in a one step chromatographic run. After separation on a strong cation exchange column, the eluted components are detected using a UV and RI detector system in series. The quaternaries present in organoclays (e.g., BENTONE type products) can also be identified by prior destruction of the silicate with hydrofluoric acid followed by chromatography of the residual quat fluorides. PMID:3667837

Spagnolo, F; Hatcher, M T; Faulseit, B K

1987-09-01

393

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

394

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

395

Fluorescence characteristics of aryl boronic acid derivate (PBA).  

Science.gov (United States)

The absorption and fluorescence spectra of newly synthesized aryl boronic acid derivative namely Phenyl boronic acid (PBA) have been recorded in various solvents of different polarities. The ground state dipole moment of PBA was obtained from quantum chemical calculations. Solvatochromic correlations were used to estimate the ground state (?g) and excited state (?e) dipole moments. The excited state dipole moments are observed to be greater than the ground state dipole moments. Further, the ground and excited state dipole moments are not parallel but subtend by an angle of 70. The changes in dipole moment (??) were calculated both from solvatochromic shift method and microscopic solvent polarity parameter (ET(N)), and the values are compared. Solvent effects on the absorption and fluorescence spectra were quantified using Reichardt's and bulk solvent polarity parameters were complemented by the results of the Kamlet-Taft treatment. PMID:25463054

Patil, S S; Muddapur, G V; Patil, N R; Melavanki, R M; Kusanur, R A

2015-03-01

396

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

397

Isolable aryl-substituted silyl radicals: synthesis, characterization, and reactivity.  

Science.gov (United States)

Isolable aryl-substituted silyl radicals (tBu2 MeSi)2(Ar)Si() (Ar = C6H5, 4-tBuC6H4, 4-PhC6H4, 3,5-tBu2C6H3) 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-tBu2C6H3 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

398

Pd-Catalyzed Oxidative Arylation of Cinnamylphosphonates: An Efficient Synthesis of (Z)-Alkenylphosphonates  

Energy Technology Data Exchange (ETDEWEB)

Various alkenylphosphonates were prepared via the palladium-catalyzed oxidative arylation of cinnamylphosphonates with arenes. The regioselectivity during the ?-H elimination of the corresponding alkylpalladium intermediate was governed most likely by steric factors.

Lee, Hyun Seung; Lim, Cheol Hee; Lee, Hyun Ju; Kim, Jae Nyoung [Chonnam National Univ., Gwangju (Korea, Republic of)

2012-11-15

399

Pd-Catalyzed Oxidative Arylation of Cinnamylphosphonates: An Efficient Synthesis of (Z)-Alkenylphosphonates  

International Nuclear Information System (INIS)

Various alkenylphosphonates were prepared via the palladium-catalyzed oxidative arylation of cinnamylphosphonates with arenes. The regioselectivity during the ?-H elimination of the corresponding alkylpalladium intermediate was governed most likely by steric factors

400

Pd(II)-Catalyzed para-Selective CH Arylation of mono-Substituted Arenes  

OpenAIRE

Pd-catalyzed para-selective CH arylation of mono-substituted arenes including toluene is developed for the first time using F+ as a bystanding oxidant. This finding provides a new retrosynthetic disconnection for biaryl synthesis.

Wang, Xisheng; Leow, Dasheng; Yu, Jin-quan

2011-01-01

401

4-Aryl-2-anilinopyrimidines as corticotropin-releasing hormone (CRH) antagonists.  

Science.gov (United States)

A series of 4-aryl-2-(N-ethylanilino)pyrimidines has been synthesized as corticotropin-releasing hormone (CRH) inhibitors. The effect of substitution on each aromatic ring on receptor binding was investigated. PMID:10230640

Cocuzza, A J; Hobbs, F W; Arnold, C R; Chidester, D R; Yarem, J A; Culp, S; Fitzgerald, L; Gilligan, P J

1999-04-01

402

Iron- and Cobalt-Catalyzed Arylation of Azetidines, Pyrrolidines, and Piperidines with Grignard Reagents.  

Science.gov (United States)

Iron- and cobalt-catalyzed cross-couplings between iodo-azetidines, -pyrrolidines, -piperidines, and Grignard reagents are disclosed. The reaction is efficient, cheap, chemoselective and tolerates a large variety of (hetero)aryl Grignard reagents. PMID:25401684

Barr, Baptiste; Gonnard, Laurine; Campagne, Rmy; Reymond, Sbastien; Marin, Julien; Ciapetti, Paola; Brellier, Marie; Gurinot, Amandine; Cossy, Janine

2014-11-17

403

From ?-arylation of olefins to acylation with aldehydes: a journey in regiocontrol of the Heck reaction.  

Science.gov (United States)

The Pd-catalyzed Mizoroki-Heck reaction of olefins with aryl halides, more often simply called the Heck reaction, was recently recognized with the 2010 Nobel Prize in chemistry. Although highly selective with electron-deficient olefins, which generally yield the linear ?-arylated product exclusively, the Heck reaction is less satisfactory with electron-rich olefins. This substrate typically generates a mixture of both ?- and ?-arylated regioisomeric products, hampering wider application of the reaction in chemical synthesis. Pioneering studies by a number of researchers revealed that high ?-regioselectivity could be obtained under Pd-diphosphine catalysis either through (i) the substitution of aryl triflates for halides or (ii) the addition of stoichiometric silver or thallium salts when aryl halides are used. Under these conditions, the arylation is believed to proceed via an ionic pathway. However, silver introduces added cost, thallium salts are toxic, and triflates are generally commercially unavailable, base sensitive, and thermally labile. Believing that the ionic pathway would be promoted in an ionic medium, in the early 2000s, we attempted the Pd-catalyzed arylation of the benchmark electron-rich olefin butyl vinyl ether with aryl bromides in an imidazolium ionic liquid. We were delighted to observe that highly regioselective ?-arylation could readily be accomplished, with no need for silver additives, thallium additives, or aryl triflates. A range of other electron-rich olefins has since been shown to be viable as well. The high ?-selectivity probably results from the high ionic strength of the medium, which facilitates the dissociation of halide anions from the [L(2)Pd(Ar)X] intermediate, channeling the arylation into the ionic pathway. Hydrogen bonding interactions may also play a role, however. We subsequently discovered that the ?-arylation can indeed be significantly accelerated by a hydrogen bond donor salt, in both ionic liquids and common solvents. Evidence shows that the concentration of the cationic Pd(II)-olefin species along the ionic pathway is increased as a result of hydrogen bonding between the hydrogen bond donor and the halide anion. More recently, we reported that cheaper and greener alcohols allow the Heck arylation of electron-rich olefins to proceed in a much faster, productive, and totally ?-regioselective manner, circumventing the need for an ionic medium or hydrogen bond donor salt. In particular, aryl chlorides with diverse properties have been demonstrated to be viable substrates for the first time. Significantly, it appears that ethylene glycol facilitates both the oxidative addition of ArCl to Pd(0) and the subsequent dissociation of chloride from Pd(II). A closely related reaction, acylation of aryl halides with aldehydes, was also developed. Proceeding via the intermediacy of an electron-rich enamine, this Pd-pyrrolidine cooperative catalysis affords alkyl aryl ketones in a straightforward manner, extending the Heck reaction from olefins to aldehydes. PMID:21612205

Ruan, Jiwu; Xiao, Jianliang

2011-08-16

404

B-11 NMR-STUDIES OF AN ARYL BORONIC ACID BOUND TO CHYMOTRYPSIN AND SUBTILISIN  

OpenAIRE

The binding of aryl boronic acids to ?-chymotrypsin and subtilisin has been studied by 11B NMR spectroscopy; evidence is provided for the direct spectroscopic observation of a tetrahedral enzyme/boromate complex. 1991.

Baldwin, J.; Claridge, T.; Derome, A.; Schofield, C.; Smith, B.

1991-01-01

405

Cyprodinil as an activator of aryl hydrocarbon receptor.  

Science.gov (United States)

Cyprodinil is a pyrimidinamine fungicide, used worldwide by agriculture. It is used to protect fruit plants and vegetables from a wide range of pathogens. Benzo[a]pyrene (BaP) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are toxic environmental pollutants and are prototypes of aryl hydrocarbon receptor (AHR) ligands. Although the structure of cyprodinil distinctly differs from those of BaP and TCDD, our results show that cyprodinil induced nuclear translocation of the AHR, and induced the transcriptional activity of aryl hydrocarbon response element (AHRE). Cyprodinil induced the expression of cytochrome P450 (CYP) 1A1, a well-known AHR-targeted gene, in ovarian granulosa cells, HO23, and hepatoma cells, Hepa-1c1c7. Its induction did not appear in AHR signal-deficient cells, and was blocked by the AHR antagonist, CH-223191. Cyprodinil decreased AHR expression in HO23 cells, resulting in CYP1A1 expression decreasing after it peaked at 9h of treatment in HO23 cells. Dexamethasone is a synthetic agonist of glucocorticoids. Cyprodinil enhanced dexamethasone-induced gene expression, and conversely, its induction of CYP1A1 expression was decreased by dexamethasone in HO23 cells, indicating its induction of crosstalk between the AHR and glucocorticoid receptor and its role as a potential endocrine disrupter. In addition to BaP, TCDD, and an AHR agonist, ?-NF, cyprodinil also phosphorylated extracellular signal-regulated kinase (ERK) in HO23 and Hepa-1c1c7 cells, indicating its deregulation of ERK activity. In summary, our results demonstrate that cyprodinil, similar to BaP, acts as an AHR activator, a potential endocrine disrupter, and an ERK disrupter. PMID:23228475

Fang, Chien-Chung; Chen, Fei-Yun; Chen, Chang-Rong; Liu, Chien-Chiang; Wong, Liang-Chi; Liu, Yi-Wen; Su, Jyan-Gwo Joseph

2013-02-01

406

An LFER study of the protolytic equilibria of 4-aryl-2,4-dioxobutanoic acids in aqueous solutions  

Directory of Open Access Journals (Sweden)

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

407

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  

Energy Technology Data Exchange (ETDEWEB)

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

408

Synthesis and photochemical study of substituted heterohelicenes and related compounds  

Science.gov (United States)

Helicenes with aryl electron-withdrawing or/and electron-donating groups at one/both end/s are potential candidates for second order nonlinear optical applications. We have prepared such helicenes and related compounds. A single crystal X-ray structure showed the structure and architecture of 2,7-di-1-naphthylbenzo[1,2-b:4,3-b'] dithiophene to be racemic chiral helixes. Both terminal aryl rings contribute to the ?-? stacking. Theoretically, there are two synthetic routes (A and B) for the synthesis of 2-(4-methoxylphenyl)trithia-[5]-heterohelicene and 2-(4-methoxylphenyl)-9-(4-cyanophenyl)trithia- [5]-heterohelicene. Although route A is more complicated, it is more efficient because substituents improve solubility. Introducing an electron-donating group increases the yields of all reactions in A.

Hu, Ying; Wex, Brigitte; Perkovic, Marc W.; Neckers, Douglas C.

2006-08-01

409

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

410

Direct C-H bond arylation of fluorenes with aryl chlorides catalyzed by N-heterocyclic carbene-palladium(II)-1-methylimidazole complex and further transformation of the products in a one-pot procedure.  

Science.gov (United States)

We report here the NHC-Pd(II)-Im complex 1-catalyzed direct C-H bond functionalization of the C9 position of fluorenes with aryl chlorides and further transformation of the resulting products in a one-pot procedure. Under the optimal conditions, arylated fluorenes can be obtained in moderate to almost quantitative yields using various activated and unactivated (hetero)aryl chlorides as the arylating reagents. Furthermore, if the mixture from the arylation reaction is exposed to air, the C9-oxidized products can be obtained in acceptable to good yields in a one-pot procedure. In addition, alkyl groups can also be efficiently introduced to the above mixture from the arylation reaction, producing further C9-alkylated products in good to almost quantitative yields in a one-pot procedure, thus providing an expedient, inexpensive and practical strategy for the mono- and di-functionalization of fluorenes. PMID:25231668

Ji, Ya-Yun; Lu, Li-Li; Shi, Yu-Chun; Shao, Li-Xiong

2014-11-14

411

Copper(I) bromide catalyzed arylation of cyclic enamides and naphthyl-1-acetamides using diaryliodonium salts.  

Science.gov (United States)

Copper(I) bromide catalyzed direct C-H arylation of cyclic enamides was achieved using diaryliodonium salts in the absence of base/additive at ambient temperature with high yields. A biologically active dihydro[a]benzocarbazole scaffold was synthesized using the established protocol. The scope of the current methodology was further extended for the synthesis of C4-, C7-aryl-substituted 1-naphthyl acetamides in good yields. PMID:25111372

Prakash, Muthuraj; Muthusamy, Subramaniam; Kesavan, Venkitasamy

2014-09-01

412

Direct CH Arylation of Electron-Deficient Heterocycles with Arylboronic Acids  

OpenAIRE

A direct arylation of a variety of electron-deficient heterocycles with arylboronic acids has been developed. This new reaction proceeds readily at room temperature using inexpensive reagents: catalytic silver(I)nitrate in the presence of persulfate co-oxidant. The scope with respect to heterocycle and boronic acid coupling partner is broad, and sensitive functional groups are tolerated. This method allows for rapid access to a variety of arylated heterocycles that would be more difficult to ...

Seiple, Ian B.; Su, Shun; Rodriguez, Rodrigo A.; Gianatassio, Ryan; Fujiwara, Yuta; Sobel, Adam L.; Baran, Phil S.

2010-01-01

413

Iron-catalyzed homocoupling of aryl halides and derivatives in the presence of alkyllithiums.  

Science.gov (United States)

Direct synthesis of biaryl derivatives from aryl halides takes place under very mild temperature conditions by using a ligand-free iron catalytic system. The procedure, which proceeds via an in situ quantitative aryl halide exchange with alkyllithiums, allows for excellent control of the reactivity and is in line with the sustainable development. The method is also applicable to styryl and benzyl halides and to phenylacetylene. PMID:24004324

Toummini, Dounia; Ouazzani, Fouad; Taillefer, Marc

2013-09-20

414

PEGylated Polyamidoamine Dendrimers with Bis-Aryl Hydrazone Linkages for Enhanced Gene Delivery  

OpenAIRE

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...

Yuan, Quan; Yeudall, W. Andrew; Yang, Hu

2010-01-01

415

A cooperative Pd-Cu system for direct C-H bond arylation.  

Science.gov (United States)

A novel and efficient method for C-H arylation using well-defined Pd- and Cu-NHC systems has been developed. This process promotes the challenging construction of C-C bonds from arenes or heteroarenes using aryl bromides and chlorides. Mechanistic studies show that [Cu(OH)(NHC)] plays a key role in the C-H activation and is involved in the transmetallation with the Pd-NHC co-catalyst. PMID:24976025

Lesieur, Mathieu; Lazreg, Fama; Cazin, Catherine S J

2014-08-18

416

Synthesis of 5,5-Disubstituted Butenolides Based on a Pd-Catalyzed -Arylation Strategy  

OpenAIRE

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 L.

2009-01-01

417

Unprecedentedly mild direct Pd-catalyzed arylation of oxazolo[4,5-b]pyridine  

DEFF Research Database (Denmark)

Pd-catalyzed C-2 arylation of oxazolo[4,5-b]pyridine proceeds efficiently at 30 degrees C and tolerates a variety of aryl halides, including derivatized amino acids for which no racemization was observed during the reaction. Experimental evidence for facile deprotonation of oxazolo[4,5-b]pyridine under the reaction conditions is presented and the nature of the anionic intermediates is computationally examined. (c) 2006 Elsevier Ltd. All rights reserved.

Zhuravlev, Fedor

2006-01-01

418

Asymmetric synthesis of quaternary aryl amino acid derivatives via a three-component aryne coupling reaction  

OpenAIRE

A method was developed for the synthesis of ?-alkyl, ?-aryl-bislactim ethers in good to excellent yields and high diastereoselectivities, consisting of a facile one-pot procedure in which the aryl group is introduced by means of a nucleophilic addition to benzyne and the alkyl group by alkylation of a resultant benzylic anion. Hydrolysis of the sterically less hindered adducts gave the corresponding quaternary amino acids with no racemization, whereas hydrolytic ring opening gave th...

Jones, Elizabeth P.; Peter Jones; White, Andrew J. P.; Barrett, Anthony G. M.

2011-01-01

419

Mutation analysis of aryl hydrocarbon receptor interacting protein (AIP) gene in colorectal, breast, and prostate cancers  

OpenAIRE

Germline mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene were recently identified in individuals with pituitary adenoma predisposition (PAP). These patients have prolactin (PRL) or growth hormone (GH) oversecreting pituitary adenomas, the latter exhibiting acromegaly or gigantism. Loss-of-heterozygosity (LOH) analysis revealed that AIP is lost in PAP tumours, suggesting that it acts as a tumour-suppressor gene. Aryl hydrocarbon receptor interacting protein is involve...

Georgitsi, M.; Karhu, A.; Winqvist, R.; Visakorpi, T.; Waltering, K.; Vahteristo, P.; Launonen, V.; Aaltonen, L. A.

2007-01-01

420

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

421

Synthesis and NMR Studies of (E)-1-Aryl-3-(2-pyrrolyl)-2-propenones and (E)-3-Aryl-1-(2-pyrrolyl)-2-propenones  

International Nuclear Information System (INIS)

Series of (E)-1-aryl-3-(2-pyrrolyl)-2-propenones, that were aldol condensation products between pyrrole-2-carbaldehyde and m- and p-substituted acetophenones, were prepared and their 1H and 13C NMR spectra were examined to obtain the information on the conformation of the enone system. Similar studies were carried out with (E)-3-aryl-1-(2-pyrrolyl)-2-propenones that were prepared from 2-acetylpyrrole and m- and p-substituted benzaldehydes. The substituent chemical shifts were studied by applying the Hammett relationship

422

Synthesis of novel 1,2-benzothiazine 1,1-dioxide-3-ethanone oxime N-aryl acetamide ether derivatives as potent anti-inflammatory agents and inhibitors of monocyte-to-macrophage transformation.  

Science.gov (United States)

A series of novel 1,2-benzothiazine 1,1-dioxide-3-ethanone oxime N-aryl acetamide ether derivatives 7a-h and 9a-h were synthesized starting from sodium salt of saccharin 1 in series of steps. Final compounds 7a-h and 9a-h were evaluated for the anti-inflammatory activity and their ability to inhibit monocyte-to-macrophage transformation. Compounds 7e, 9b, 9e and 9h showed impressive anti-inflammatory activities (TNF-?, IL-8 and MCP-1) at micro molar concentration which was found to be better than positive control i.e., piroxicam. Compound 9e marginally and compound 9h significantly inhibited PMA-induced MMP-9 gelatinase activity. Also compounds 9e and 9h greatly inhibited the PMA-induced monocyte-to-macrophage transformation, a pre-requisite step in the formation of atheroma. PMID:24531227

Gannarapu, Malla Reddy; Vasamsetti, Sathish Babu; Punna, Nagender; Royya, Naresh Kumar; Pamulaparthy, Shanthan Rao; Nanubolu, Jagadeesh Babu; Kotamraju, Srigiridhar; Banda, Narsaiah

2014-03-21

423

N-heterocyclic carbene-palladium(II)-1-methylimidazole complex catalyzed ?-arylation of oxindoles with aryl chlorides and aerobic oxidation of the products in a one-pot procedure.  

Science.gov (United States)

NHC-Pd(II)-Im complex 1 was found to be an effective catalyst for the ?-arylation of unprotected oxindoles with aryl chlorides to give products 4 in 44-98% yields under a N2 atmosphere. Furthermore, if the reactions were first performed under conditions identical to those for the ?-arylation reaction for 12 h and then exposed to air for another 3 h, 3-aryl-3-hydroxy-2-oxindoles 5 can be obtained in 49-84% yields in a one-pot procedure. PMID:23451859

Xiao, Zheng-Kang; Yin, Hui-Ying; Shao, Li-Xiong

2013-03-15

424

Pd-Catalyzed O-Arylation of Ethyl Acetohydroximate: Synthesis of O-Arylhydroxylamines and Substituted Benzofurans  

OpenAIRE

An efficient Pd catalyst for the O-arylation of ethyl acetohydroximate with aryl chlorides, bromides, and iodides has been developed. Ethyl acetohydroximate serves as an efficient hydroxylamine equivalent for C?O cross-coupling, thereby allowing for the preparation of O-arylhydroxylamines from simple aryl halides. Short reaction times and broad substrate scope, including heteroaryl coupling partners, allow access to O-arylhydroxylamines that would be difficult to prepare in a single step by...

Maimone, Thomas J.; Buchwald, Stephen L.

2010-01-01

425

Evaluation of sensitizers found in wastewater from paper recycling areas, and their activation of the aryl hydrocarbon receptor in vitro.  

Science.gov (United States)

The in vitro potential of sensitizers and related compounds (SRCs) originating from impurities in waste paper in activating the human aryl hydrocarbon receptor (AhR) ? was assessed using yeast reporter gene as well as cytochrome P450 (CYP)1A1 and ethoxyresorufin O-deethylase (EROD) assays. In the yeast assay, eight compounds exhibited agonist activity, and their activity relative to ?-naphthoflavone (BNF) ranged from 1.4 10(-4) to 8.3 10(-2), with the highest activity observed for benzyl 2-naphthyl ether (BNE). In the EROD assay, six compounds caused a more significant induction of CYP1A-dependent activity than did the vehicle control at 50 ?M (p<0.01), and their induction levels were 5.1- to 11-fold more potent; 1,2-bis(3-methylphenoxy)ethane (BME) was the most effective inducer. The water from the waste paper recycling area was fractioned using solid-phase extraction (SPE) combined with a C18 disk and florisil cartridge. In gas chromatography-mass spectrometry (GC-MS) analysis, SRCs were detected in the first fraction, at a total concentration of 5.5 ?g/L. This fraction also activated AhR, and its activity, expressed as a BNF equivalent value, was 0.42 nM in the yeast assay. The contribution ratio of active compounds accounted for up to 34% and 4.4% observed activity of the fraction and total samples, respectively. To our knowledge, this is the first study to show that paper industry-related compounds, namely aromatic sensitizers, activate AhR by using a yeast assay and HepG2 cells. PMID:24950494

Terasaki, Masanori; Yasuda, Michiko; Shimoi, Kayoko; Jozuka, Kazuhiko; Makino, Masakazu; Shiraishi, Fujio; Nakajima, Daisuke

2014-09-15

426

Rh(I)-Catalyzed Arylation of Heterocycles via C-H Bond Activation: Expanded Scope Through Mechanistic Insight  

OpenAIRE

A practical, functional group tolerant method for the Rh-catalyzed direct arylation of a variety of pharmaceutically important azoles with aryl bromides is described. Many of the successful azole and aryl bromide coupling partners are not compatible with methods for the direct arylation of heterocycles using Pd(0) or Cu(I) catalysts. The readily prepared, low molecular weight ligand, Z-1-tert-butyl-2,3,6,7-tetrahydrophosphepine, which coordinates to Rh in a bidentate P-olefin fashion to provi...

Lewis, Jared C.; Berman, Ashley M.; Bergman, Robert G.; Ellman, Jonathan A.

2008-01-01

427

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)

428

Computational Study on the Acid Catalyzed Reactions of Fluorine-Containing 2,4-Dialkoxy-3,4-dihydro-2H-pyrans with Aromatic Compounds  

Directory of Open Access Journals (Sweden)

Full Text Available 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 different products under each condition were studied on the basis of DFT calculations. Moreover, the proposed mechanism for the reaction of 5-trifluoroacetyl-6-trifluoromethyl-3,4-dihydro-2H-pyran (5 with aromatic compounds affording butadiene derivatives (6 exclusively was also discussed based on the calculations and comparison with the reactivity of pyrylium intermediate (7.

Norio Ota

2012-02-01

429

Phosphorgruppenhaltige Carbonsaeurederivate mit organisch polymerisierbaren Gruppen  

OpenAIRE

WO2004026884 A UPAB: 20040527 NOVELTY - omega -Phosphonyl-(thio)carboxylic ester and N-substituted amide compounds (I), in which the ester or N-substituent is linear or branched and has polymerizable group(s), are new. DETAILED DESCRIPTION - omega -Phosphonyl(thio)carboxylic ester and N-substituted amide compounds of formula ((R1)(R2)P(O)-(CHR3)-(CHR4)- (CHR5)m-C(O)X-)n (B) (I) are new; X = O, NH, NR6 or S; R1, R2 = H or (substituted) alk(en)yl(oxy), (alkyl)aryl(oxy) or arylalkyl(oxy); R3, R4...

Wolter, H.

2004-01-01

430

Synthesis of New Bioactive Sulfur Compounds Bearing Heterocyclic Moiety and Their Analytical Applications  

OpenAIRE

Some new bioactive sulfur compounds bearing heterocyclic nitrogen moieties such as 3- imino2-thioxo-4,5-dihydro- thiazolidin 4-one (3), 3-imino 2-thioxo -3,4,5,6-tetrahydro-1, 3-thiazine-4, 6- (2 H)dione(4), N- substituted pyrazol -3,5-dione (10) , 1,3 disubstituted -2-thioxo-pyrimidin-4,6 dione (11) and di (3,5-diaminopyrazolin-1-yl)thioketone (13) derived from dithioc formic acid hydrazide (1) and thiocarbohydrazide (7)were prepared via conden...

Makki, Mohammad S. T.; Abdel-rahman, Reda M.; El-shahawi, Mohammad S.

2011-01-01

431

Polymorphism of the aryl-hydrocarbon receptor gene in intron 10 of human cancers  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Polychlorinated dibenzo-p-dioxins (PCDDs) and related halogenated aromatic hydrocarbons (e.g., PCDFs), often called "dioxins", are ubiquitously present environmental contaminants. Some of them, notably 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are among the most toxic synthetic compounds known. Th [...] e biological effects of dioxins are mediated via the aryl hydrocarbon receptor (AhR). Mutations in the AhR transactivation domain are linked to sensitivity to the acute lethality of TCDD. We present here a study of AhR gene polymorphism in normal and cancer human tissues affecting pre-mRNA splicing in the AhR gene-coding transactivation domain region (exon 10, intron 10, exon 11 region), previously shown to be associated with AhR dysfunction. We tested 126 pairs of normal and cancer tissue samples from liver, lung, stomach, kidney, mucous, breast, and pancreas of 49 males and 77 females (45-70 years of age). We used in vitro splicing assay, RT-PCR and sequencing methods. Our results showed that in an in vitro system it is possible to reconstitute cellular pre-mRNA splicing events. Tested cancer tissues did not contain mutations in the AhR transactivation domain region when the DNA sequences were compared with those from normal tissues. There were also no differences in AhR mRNA splice variants between normal and malignant breast tissues and no polymorphisms in the studied regions or cDNA.

M., Rocas; E., Jakubauskiene; A., Kanopka.

1112-11-01

432

Toxicological implications of polymorphisms in receptors for xenobiotic chemicals: The case of the aryl hydrocarbon receptor  

International Nuclear Information System (INIS)

Mechanistic toxicology has predominantly been focused on adverse effects that are caused by reactive metabolites or by reactive oxygen species. However, many important xenobiotics exert their toxicity, not by generating reactive products, but rather by altering expression of specific genes. In particular, some environmental contaminants target nuclear receptors that function as regulators of transcription. For example, binding of xenobiotic chemicals to steroid receptors is a principle mechanism of endocrine disruption. The aryl hydrocarbon receptor (AHR) mediates toxicity of dioxin-like compounds. In mice, a polymorphism in the AHR ligand-binding domain reduces binding affinity by about 10-fold in the DBA/2 strain compared with the C57BL/6 strain; consequently, dose-response curves for numerous biochemical and toxic effects are shifted about one log to the right in DBA/2 mice. In the Han/Wistar (Kuopio) (H/W) rat strain, a polymorphism causes a deletion of 38 or 43 amino acids from the AHR transactivation domain. This deletion is associated with a greater than 1000-fold resistance to lethality from 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Genes in the conventional AH gene battery (e.g. CYP1A1, CYP1A2, CYP1B1, ALDH3A1, NQO1 and UGT1A1) remain responsive to TCDD in H/W rats despite the large deletion. However, the deletion may selectively alter the receptor's ability to dysregulate specific genes that are key to dioxin toxicity. We are identifying these genes using ity. We are identifying these genes using an expression array approach in dioxin-sensitive vs. dioxin-resistant rat strains and lines. Polymorphisms exist in the human AH receptor, but thus far they have not been shown to have any substantial effect on human responses to AHR-ligands

433

Harman induces CYP1A1 enzyme through an aryl hydrocarbon receptor mechanism  

International Nuclear Information System (INIS)

Harman is a common compound in several foods, plants and beverages. Numerous studies have demonstrated its mutagenic, co-mutagenic and carcinogenic effects; however, the exact mechanism has not been fully identified. Aryl hydrocarbon receptor (AhR) is a transcription factor regulating the expression of the carcinogen-activating enzyme; cytochrome P450 1A1 (CYP1A1). In the present study, we examined the ability of harman to induce AhR-mediated signal transduction in human and rat hepatoma cells; HepG2 and H4IIE cells. Our results showed that harman significantly induced CYP1A1 mRNA in a time- and concentration-dependent manner. Similarly, harman significantly induced CYP1A1 at protein and activity levels in a concentration-dependent manner. Moreover, the AhR antagonist, resveratrol, inhibited the increase in CYP1A1 activity by harman. The RNA polymerase inhibitor, actinomycin D, completely abolished the CYP1A1 mRNA induction by harman, indicating a transcriptional activation. The role of AhR in CYP1A1 induction by harman was confirmed by using siRNA specific for human AhR. The ability of harman to induce CYP1A1 was strongly correlated with its ability to stimulate AhR-dependent luciferase activity and electrophoretic mobility shift assay. At post-transcriptional and post-translational levels, harman did not affect the stability of CYP1A1 at the mRNA and the protein levels, excluding other mechanisms participating in the obtained effects. We concluded that harman can did effects. We concluded that harman can directly induce CYP1A1 gene expression in an AhR-dependent manner and may represent a novel mechanism by which harman promotes mutagenicity, co-mutagenicity and carcinogenicity.

434

In vitro cytotoxicity and apoptotic inducing activity of the synthesized 4-aryl-4H-chromenes derivatives against human cancer cell lines  

Directory of Open Access Journals (Sweden)

Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: 4-Aryl-4H-chromenes are novel anticancer agents which induce apoptosis in cancer cells. These compounds were found to induce apoptosis by targeting the tubulin/microtubule system in cell proliferation process. The aim of this study was to report cyototoxic and apoptosis inducing activities of a new series of synthesized 4-aryl-4H-chromenes compounds."n"n Methods: The in vitro cytotoxic activity of the synthesized 4-aryl-4H-chromenes was investigated against a paned of human cancer cell lines including MCF-7 (breast carcinoma, A549 (lung carcinoma, HEPG-2 (liver carcinoma, SW-480 (colon adenocarcinoma, U87-MG (glioblastoma, 1321N1 (astrocytoma, and DAOY (medulloblastoma. The percentage of growth inhibitory activity was evaluated using MTT colorimetric assay versus controls not treated with test derivatives. The data for etoposide, a well known anticancer drug, was included for comparison. For each compound, the 50% inhibitory concentration (IC50 were determined. Apoptosis inducing activity were assessed by DAPI staining."n"n Results: Preliminary screening showed that those chromenes analogs bearing phenyl-isoxazole-3-yl substitution or the derivatives containing methoxyphenyl in chromene ring exhibited cytotoxic and apoptotic inducing activity comparable with or even superior than the reference drug, etoposide. The compounds without this type of substitution have lower activity. "n"nConclusions: Replacement of 3, 4, 5-trimethoxyphenyl group with thiazol ring in the synthesized derivatives reduced the cytotoxic activity. However, the derivatives with phenyl-isoxazole analogue showed potent cytotoxic and apoptotic inducing activity.

Mohagheghi MA

2009-09-01

435

THE IMPACT OF PHTHALATE ESTERS IN THE ENVIRONMENTAL AND HUMAN HEALTH ARE THESE COMPOUNDS, A NECESSARY EVIL?  

OpenAIRE

Phthalates are a group of diesters of phthalic acid (dialkyl or alkyl aryl esters of 1,2-benzenedicarboxylicacid) and they are primarily used as plasticizers (substances added to plastics to increase their flexibility). Asthe phthalates are not chemically bonded to the polymer, these compounds can migrate from the plasticmaterial to the environment and, consequently, they are found in food, water, soil, air and in the human body.This article discusses the problem of using those compounds, the...

Dos Santos, Marcel Silveira

2011-01-01

436

Design, synthesis, and biological evaluation of 3-aryl-3-hydroxy-1-phenylpyrrolidine derivatives as novel androgen receptor antagonists.  

Science.gov (United States)

We designed and synthesized a series of 3-aryl-3-hydroxy-1-phenylpyrrolidine derivatives D and evaluated their potential as novel androgen receptor (AR) antagonists therapeutically effective against castration-resistant prostate cancer (CRPC). Introduction of a methyl group at the 2-position (R(2)) of the pyrrolidine ring increased the AR binding affinity. The (2S,3R) configuration of the pyrrolidine ring was favorable for the AR antagonistic activity. It was found that introduction of an amide substituent (R(1)) and a pyridin-3-yl group (Q) was effective for reducing the AR agonistic activity which appeared during the optimization of lead compound 6. Compound 54 showed potent antitumor effects against a CRPC model of LNCaP-hr cell line in a mouse xenograft, in which bicalutamide exhibited only partial suppression of tumor growth. Thus, the pyrrolidine derivatives such as 54 are novel AR antagonists, and their properties having efficacy against CRPC are distinct from those of a representative first-generation antagonist, bicalutamide. PMID:23199477

Yamamoto, Satoshi; Kobayashi, Hiromi; Kaku, Tomohiro; Aikawa, Katsuji; Hara, Takahito; Yamaoka, Masuo; Kanzaki, Naoyuki; Hasuoka, Atsushi; Baba, Atsuo; Ito, Mitsuhiro

2013-01-01

437

Aryl sulfate formation in sea urchins (Strongylocentrotus droebachiensis) ingesting marine algae (Fucus distichus) containing 2,6-dimethylnapthalene  

International Nuclear Information System (INIS)

The metabolism of tritiated 2,6-dimethylnapthalene (2,6-DMN) was studied in sea urchins (Strongylocentrotus droebachiensis) feeding on marine algae (Fucus distichus). The Fucus accumulated this hydrocarbon from sea water without converting it to metabolites. Most of the tritium accumulated by the sea urchins (e.g., 70.8% after 3 days) from feeding on 2,6-DMN-exposed Fucus was present in the exoskeleton (shell and spines). Moreover, after 3 days feeding, about 90% of the tritium in the total metabolite fraction of the gonads and digestive tract of the sea urchin was present as sulfate derivatives. These metabolites were identified through hydrolysis with aryl sulfatase, followed by thin-layer chromatography of the products. After 14 days of feeding, the tritium associated with the sulfate derivatives decreased in the gonads and digestive tract to 61 and 65%, respectively, of the total metabolite fraction. Hydroxy compounds from sulfatase hydrolysis were chromatographed using multiple elutions with toluene. The hydroxy isomers were separated and the R/sub f/ values were compared to those of pure reference compounds. The data indicated that 80% of the 2,6-dimethylnaphtyl sulfate contained the sulfate on the 1 and/or 3 position of the aromatic ring. Moreover, 6-methyl-2-naphthalenemethanol was not detected, which implies that sea urchins, unlike fish, metabolize alkyl-substituted aromatic hydrocarbons primarily through aromatic ring oxidationsng oxidations

438

Compound Interest  

Science.gov (United States)

Albert Einstein called compound interest the 8th wonder of the world. Find out why compound interest and the time value of money are so important. What is Interest Click on the following link to read about the different types of interest. Loans and Interest So why learn about compound interest? Using time and interest to your advantage, you can make more money than you have ever dreamed of. See how the time value of ...

Ms. Riches

2007-10-16

439

Evodiamine as a novel antagonist of aryl hydrocarbon receptor  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} Evodiamine interacted with the AhR. {yields} Evodiamine inhibited the specific binding of [{sup 3}H]-TCDD to the AhR. {yields} Evodiamine acts as an antagonist of the AhR. -- Abstract: Evodiamine, the major bioactive alkaloid isolated from Wu-Chu-Yu, has been shown to interact with a wide variety of proteins and modify their expression and activities. In this study, we investigated the interaction between evodiamine and the aryl hydrocarbon receptor (AhR). Molecular modeling results revealed that evodiamine directly interacted with the AhR. Cytosolic receptor binding assay also provided the evidence that evodiamine could interact with the AhR with the K{sub i} value of 28.4 {+-} 4.9 nM. In addition, we observed that evodiamine suppressed the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced nuclear translocation of the AhR and the expression of CYP1A1 dose-dependently. These results suggested that evodiamine was able to bind to the AhR as ligand and exhibit antagonistic effects.

Yu, Hui [State Key Laboratory of Trauma, Burns, and Combined Injury, Department 1, Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China); Department of Laboratory Medicine, The Affiliated Tenth People' s Hospital, Tongji University, Shanghai 200072 (China); Tu, Yongjiu; Zhang, Chun; Fan, Xia; Wang, Xi [State Key Laboratory of Trauma, Burns, and Combined Injury, Department 1, Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China); Wang, Zhanli [College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310014 (China); Liang, Huaping, E-mail: huaping_liang@yahoo.com.cn [State Key Laboratory of Trauma, Burns, and Combined Injury, Department 1, Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing 400042 (China)

2010-11-05

440

Evodiamine as a novel antagonist of aryl hydrocarbon receptor  

International Nuclear Information System (INIS)

Research highlights: ? Evodiamine interacted with the AhR. ? Evodiamine inhibited the specific binding of [3H]-TCDD to the AhR. ? Evodiamine acts as an antagonist of the AhR. -- Abstract: Evodiamine, the major bioactive alkaloid isolated from Wu-Chu-Yu, has been shown to interact with a wide variety of proteins and modify their expression and activities. In this study, we investigated the interaction between evodiamine and the aryl hydrocarbon receptor (AhR). Molecular modeling results revealed that evodiamine directly interacted with the AhR. Cytosolic receptor binding assay also provided the evidence that evodiamine could interact with the AhR with the Ki value of 28.4 4.9 nM. In addition, we observed that evodiamine suppressed the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced nuclear translocation of the AhR and the expression of CYP1A1 dose-dependently. These results suggested that evodiamine was able to bind to the AhR as ligand and exhibit antagonistic effects.

441

8-Aryl- and alkyloxycaffeine analogues as inhibitors of monoamine oxidase.  

Science.gov (United States)

Recently it was reported that a series of 8-benzyloxycaffeine analogues are potent reversible inhibitors of human monoamine oxidase (MAO) A and B. In an attempt to discover additional C8 oxy substituents of caffeine that lead to potent MAO inhibition, a series of related 8-aryl- and alkyloxycaffeine analogues were synthesized and their MAO-A and -B inhibition potencies were compared to those of the 8-benzyloxycaffeines. The results document that while the 8-substituted-oxycaffeine analogues inhibited both human MAO isoforms, they displayed a high degree of selectivity for MAO-B. 8-(3-Phenylpropoxy)caffeine, 8-(2-phenoxyethoxy)caffeine and 8-[(5-methylhexyl)oxy]caffeine were found to be the especially potent MAO-B inhibitors with IC(50) values ranging from 0.38 to 0.62?M. These inhibitors are therefore 2.5-4.6 fold more potent MAO-B inhibitors than is 8-benzyloxycaffeine (IC(50)=1.77?M). It is also demonstrated that, analogous to 8-benzyloxycaffeine, halogen substitution on the phenyl ring of the C8 substituent significantly enhances MAO binding affinity. For example, the most potent MAO-B inhibitor of the present series is 8-[2-(4-bromophenoxy)ethoxy]caffeine with an IC(50) value of 0.166?M. This study also reports possible binding orientations of selected oxy caffeines within the active site cavities of MAO-A and MAO-B. PMID:21621312

Strydom, Belinda; Bergh, Jacobus J; Petzer, Jacobus P

2011-08-01

442

An Efficient Process for Pd-Catalyzed C?N Cross-Coupling Reactions of Aryl Iodides: Insight Into Controlling Factors  

OpenAIRE

An investigation into Pd-catalyzed C?N cross-coupling reactions of aryl iodides is described. NaI is shown to have a significant inhibitory effect on these processes. By switching to a solvent system in which the iodide byproduct was insoluble, reactions of aryl iodides were accomplished with the same efficiencies as aryl chlorides and bromides. Using catalyst systems based on certain biarylphosphine ligands, aryl iodides were successfully reacted with an array of primary and secondary amin...

Fors, Brett P.; Davis, Nicole R.; Buchwald, Stephen L.

2009-01-01

443

Palladium-catalyzed ?-arylation of zinc enolates of esters: reaction conditions and substrate scope.  

Science.gov (United States)

The intermolecular ?-arylation of esters by palladium-catalyzed coupling of aryl bromides with zinc enolates of esters is reported. Reactions of three different types of zinc enolates have been developed. ?-Arylation of esters occurs in high yields with isolated Reformatsky reagents, with Reformatsky reagents generated from ?-bromo esters and activated zinc, and with zinc enolates generated by quenching alkali metal enolates of esters with zinc chloride. The use of zinc enolates, instead of alkali metal enolates, greatly expands the scope of the arylation of esters. The reactions occur at room temperature or at 70 C with bromoarenes containing cyano, nitro, ester, keto, fluoro, enolizable hydrogen, hydroxyl, or amino functionality and with bromopyridines. The scope of esters encompasses acyclic acetates, propionates, and isobutyrates, ?-alkoxyesters, and lactones. The arylation of zinc enolates of esters was conducted with catalysts bearing the hindered pentaphenylferrocenyl di-tert-butylphosphine (Q-phos) or the highly reactive dimeric Pd(I) complex {[P(t-Bu)3]PdBr}2. PMID:23931445

Hama, Takuo; Ge, Shaozhong; Hartwig, John F

2013-09-01

444

Configuration-dependent electronic and magnetic properties of graphene monolayers and nanoribbons functionalized with aryl groups  

International Nuclear Information System (INIS)

Graphene monolayers functionalized with aryl groups exhibit configuration-dependent electronic and magnetic properties. The aryl groups were adsorbed in pairs of neighboring atoms in the same sublattice A (different sublattices) of graphene monolayers, denoted as the M2AA (M2AB) configuration. The M2AA configuration behaved as a ferromagnetic semiconductor. The band gaps for the majority and minority bands were 1.1 eV and 1.2 eV, respectively. The M2AB configuration behaved as a nonmagnetic semiconductor with a band gap of 0.8 eV. Each aryl group could induce 1 Bohr magneton (?B) into the molecule-graphene system. Armchair graphene nanoribbons (GNRs) exhibited the same configuration-dependent magnetic properties as the graphene monolayers. The net spin of the functionalized zigzag GNRs was mainly localized on the edges demonstrating an adsorption site-dependent magnetism. For the zigzag GNRs, both the M2AA and M2AB configurations possibly had a magnetic moment. Each aryl group could induce 1.53.5 ?B into the molecule-graphene system. There was a metal-to-insulator transition after adsorption of the aryl groups for the zigzag GNRs

445

Configuration-dependent electronic and magnetic properties of graphene monolayers and nanoribbons functionalized with aryl groups  

Energy Technology Data Exchange (ETDEWEB)

Graphene monolayers functionalized with aryl groups exhibit configuration-dependent electronic and magnetic properties. The aryl groups were adsorbed in pairs of neighboring atoms in the same sublattice A (different sublattices) of graphene monolayers, denoted as the M{sub 2}{sup AA} (M{sub 2}{sup AB}) configuration. The M{sub 2}{sup AA} configuration behaved as a ferromagnetic semiconductor. The band gaps for the majority and minority bands were 1.1 eV and 1.2 eV, respectively. The M{sub 2}{sup AB} configuration behaved as a nonmagnetic semiconductor with a band gap of 0.8 eV. Each aryl group could induce 1 Bohr magneton (?{sub B}) into the molecule-graphene system. Armchair graphene nanoribbons (GNRs) exhibited the same configuration-dependent magnetic properties as the graphene monolayers. The net spin of the functionalized zigzag GNRs was mainly localized on the edges demonstrating an adsorption site-dependent magnetism. For the zigzag GNRs, both the M{sub 2}{sup AA} and M{sub 2}{sup AB} configurations possibly had a magnetic moment. Each aryl group could induce 1.53.5 ?{sub B} into the molecule-graphene system. There was a metal-to-insulator transition after adsorption of the aryl groups for the zigzag GNRs.

Tian, Xiaoqing, E-mail: xqtian2008@gmail.com; Gu, Juan [College of Physics and Technology, Shenzhen University, Shenzhen 518060, Guangdong (China); Xu, Jian-bin, E-mail: jbxu@ee.cuhk.edu.hk [Department of Electronic Engineering and Materials Science and Technology Research Center, The Chinese University of Hong Kong, Shatin, New Territories (Hong Kong)

2014-01-28

446

Expedient synthesis of C-aryl carbohydrates by consecutive biocatalytic benzoin and aldol reactions.  

Science.gov (United States)

The introduction of aromatic residues connected by a C?C bond into the non-reducing end of carbohydrates is highly significant for the development of innovative structures with improved binding affinity and selectivity (e.g., C?aril-sLex). In this work, an expedient asymmetric "de novo" synthetic route to new aryl carbohydrate derivatives based on two sequential stereoselectively biocatalytic carboligation reactions is presented. First, the benzoin reaction of aromatic aldehydes to dimethoxyacetaldehyde is conducted, catalyzed by benzaldehyde lyase from Pseudomonas fluorescens biovar I. Then, the ?-hydroxyketones formed are reduced by using NaBH4 yielding the anti diol. After acetal hydrolysis, the aldol addition of dihydroxyacetone, hydroxyacetone, or glycolaldehyde catalyzed by the stereocomplementary D-fructose-6-phosphate aldolase and L-rhamnulose-1-phosphate aldolase is performed. Both aldolases accept unphosphorylated donor substrates, avoiding the need of handling the phosphate group that the dihydroxyacetone phosphate-dependent aldolases require. In this way, 6-C-aryl-L-sorbose, 6-C-aryl-L-fructose, 6-C-aryl-L-tagatose, and 5-C-aryl-L-xylose derivatives are prepared by using this methodology. PMID:25640727

Hernndez, Karel; Parella, Teodor; Joglar, Jess; Bujons, Jordi; Pohl, Martina; Claps, Pere

2015-02-16

447

Inhibitors of the acetyltransferase domain of N-acetylglucosamine-1-phosphate-uridylyltransferase/glucosamine-1-phosphate-acetyltransferase (GlmU). Part 2: Optimization of physical properties leading to antibacterial aryl sulfonamides.  

Science.gov (United States)

A previously described aryl sulfonamide series, originally found through HTS, targets GlmU, a bifunctional essential enzyme involved in bacterial cell wall synthesis. Using structure-guided design, the potency of enzyme inhibition was increased in multiple isozymes from different bacterial species. Unsuitable physical properties (low LogD and high molecular weight) of those compounds prevented them from entering the cytoplasm of bacteria and inhibiting cell growth. Further modifications described herein led to compounds that possessed antibacterial activity, which was shown to occur through inhibition of GlmU. The left-hand side amide and the right-hand side sulfonamides were modified such that enzyme inhibitory activity was maintained (IC(50) <0.1 ?M against GlmU isozymes from Gram-negative organisms), and the lipophilicity was increased giving compounds with LogD -1 to 3. Antibacterial activity in an efflux-pump deficient mutant of Haemophilus influenzae resulted for compounds such as 13. PMID:23099094

Stokes, Suzanne S; Albert, Robert; Buurman, Ed T; Andrews, Beth; Shapiro, Adam B; Green, Oluyinka M; McKenzie, Andrew R; Otterbein, Ludovic R

2012-12-01

448

Regioselective Multi-component Synthesis of 7-Aryl-benzo[h][1,2,4]-triazolo[5,1-b]quinazoline-5,6-diones Catalyzed by n-Propylsulfonated ?-Al{sub 2}O{sub 3}  

Energy Technology Data Exchange (ETDEWEB)

We have developed a straightforward method for the synthesis of 7-aryl-benzo[h][1,2,4]-triazolo[5,1-b] quinazoline-5,6-dione derivatives by nano n-propylsulfonated ?-Al{sub 2}O{sub 3} catalyzed three-component reaction of aldehyde, 2-hydroxy-1,4-naphthoquinone and 3-amino-1,2,4-triazole. A series of 7-aryl-benzo[h][1,2,4]-triazolo[5,1-b]quinazoline-5,6-dione derivatives have been synthesized in excellent yield (85-96%). The catalyst can be recycled up to six cycles without much decrease in catalytic activity. Environment friendly catalyst, high regioselectivity and good yield are the advantages of the method. To the best of our knowledge this is the first report on synthesis of 7-aryl-benzo[h][1,2,4]-triazolo[5,1-b]quinazoline-5,6-dione derivatives. We are evaluating anticancer activity of 4, which will be published elsewhere. Naphthoquinones constitute a major class of naturally occurring compounds, and interests in their chemistry continues unabated because of their wide range of biological and therapeutic properties such as antioxidant, antifungal, anti-inflammatory, antiallergic, antiviral, and anticancer activity.

Li, Weilin; Tian, Shuanbao; Wu, Liqiang [Xinxiang Medical Univ., Xinxiang (China)

2013-09-15

449

New N-aryl-N'-(3-(substituted)phenyl)-N'-methylguanidines as leads to potential PET radioligands for imaging the open NMDA receptor.  

Science.gov (United States)

An expansive set of N-aryl-N'-(3-(substituted)phenyl)-N'-methylguanidines was prepared in a search for new leads to prospective PET ligands for imaging of the open channel of the N-methyl-d-aspartate (NMDA) receptor in vivo. The N-aryl rings and their substituents were varied, whereas the N-methyl group was maintained as a site for potential labeling with the positron-emitter, carbon-11 (t1/2=20.4min). At micromolar concentration, over half of the prepared compounds strongly inhibited the binding of [(3)H]TCP to its binding site in the open NMDA receptor in vitro. Four ligands displayed affinities that are similar or superior to those of the promising SPECT radioligand ([(123)I]CNS1261). The 3'-dimethylamino (19; Ki 36.7nM), 3'-trifluoromethyl (20; Ki 18.3nM) and 3'-methylthio (2; Ki 39.8nM) derivatives of N-1-naphthyl-N'-(phenyl)-N'-methylguanidine were identified as especially attractive leads for PET radioligand development. PMID:25499436

Naumiec, Gregory R; Cai, Lisheng; Pike, Victor W

2015-01-15

450

Aryl hydrocarbon receptor (AHR)-active pharmaceuticals are selective AHR modulators in MDA-MB-468 and BT474 breast cancer cells.  

Science.gov (United States)

Leflunomide, flutamide, nimodipine, mexiletine, sulindac, tranilast, 4-hydroxytamoxifen, and omeprazole are pharmaceuticals previously characterized as aryl hydrocarbon receptor (AHR) agonists in various cell lines and animal models. In this study, the eight AHR-active pharmaceuticals were investigated in highly aggressive aryl hydrocarbon (Ah)-responsive BT474 and MDA-MB-468 breast cancer cell lines, and their effects on AHR protein, CYP1A1 (protein and mRNA), CYP1B1 (mRNA), and cell migration were determined. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was used as a positive control. The AHR agonist activities of the pharmaceuticals depended on structure, response, and cell context. Most compounds induced one or more AHR-mediated responses in BT474 cells, whereas in Ah-responsive MDA-MB-468 cells effects of the AHR-active pharmaceuticals were highly variable. 4-Hydroxytamoxifen, mexiletine, and tranilast did not induce CYP1A1 in MDA-MB-468 cells; moreover, in combination with TCDD, mexiletine was a potent AHR antagonist, tranilast was a partial antagonist, and 4-hydroxytamoxifen also exhibited some AHR antagonist activity. Omeprazole and, to a lesser extent, sulindac and leflunomide were full and partial AHR agonists, respectively, in both breast cancer cell lines. These data indicate that the AHR-active pharmaceuticals are selective AHR modulators, and applications of these drugs for targeting the AHR must be confirmed by studies using the most relevant cell context. PMID:22879383

Jin, Un-Ho; Lee, Syng-ook; Safe, Stephen

2012-11-01

451

N-heterocyclic carbene-palladium(II)-1-methylimidazole complex catalyzed amination between aryl chlorides and amides.  

Science.gov (United States)

We report herein that amides are excellent N-sources in the NHC-Pd(II)-Im complex 1 catalyzed amination of aryl chlorides. In the presence of KO(t)Bu, various aryl chlorides and amides can react smoothly to give the corresponding aminated products in moderate to almost quantitative yields at room temperature within 6 h. PMID:23020672

Chen, Wen-Xin; Shao, Li-Xiong

2012-10-19

452

Intramolecular Acylation of Aryl- and Aroyl-Aliphatic Acids by the Action of Pyrophosphoryl Chloride and Phosphorus Oxychloride  

Directory of Open Access Journals (Sweden)

Full Text Available Both pyrophosphoryl chloride and phosphorus oxychloride react with aryl aliphatic acids to form mixed anhydrides which undergo intramolecular acylation to afford cyclic ketones without the addition of a Friedel-Crafts catalyst. Aryl and aroylbenzoic acids could be cyclized to the corresponding anthrones and anthraquinones respectively.

Saleh Rayyan

2001-03-01

453

Homocoupling of aryl halides in flow: Space integration of lithiation and FeCl3 promoted homocoupling  

Directory of Open Access Journals (Sweden)

Full Text Available The use of FeCl3 resulted in a fast homocoupling of aryllithiums, and this enabled its integration with the halogenlithium exchange reaction of aryl halides in a flow microreactor. This system allows the homocoupling of two aryl halides bearing electrophilic functional groups, such as CN and NO2, in under a minute.

Aiichiro Nagaki

2011-08-01

454

Copper-Catalyzed N-Arylation of Amides Using (S-N-Methylpyrrolidine-2-carboxylate as the Ligand  

Directory of Open Access Journals (Sweden)

Full Text Available (S-N-methylpyrrolidine-2-carboxylate, a derivative of natural L-proline, was found to be an efficient ligand for the copper-catalyzed Goldberg-type N-arylation of amides with aryl halides under mild conditions. A variety of N-arylamides were synthesized in good to high yields.

Dong-Sheng Ma

2010-03-01

455

Effect of dioxins on regulation of tyrosine hydroxylase gene expression by aryl hydrocarbon receptor: a neurotoxicology study  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Dioxins and related compounds are suspected of causing neurological disruption. Epidemiological studies indicated that exposure to these compounds caused neurodevelopmental disturbances such as learning disability and attention deficit hyperactivity disorder, which are thought to be closely related to dopaminergic dysfunction. Although the molecular mechanism of their actions has not been fully investigated, a major participant in the process is aryl hydrocarbon receptor (AhR. This study focused on the effect of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD exposure on the regulation of TH, a rate-limiting enzyme of dopamine synthesis, gene expression by AhR. Methods N2a-R? cells were established by transfecting murine neuroblastoma Neuro2a with the rat AhR cDNA. TH expression induced by TCDD was assessed by RT-PCR and Western blotting. Participation of AhR in TCDD-induced TH gene expression was confirmed by suppressing AhR expression using the siRNA method. Catecholamines including dopamine were measured by high-performance liquid chromatography. A reporter gene assay was used to identify regulatory motifs in the promoter region of TH gene. Binding of AhR with the regulatory motif was confirmed by an electrophoretic mobility shift assay (EMSA. Results Induction of TH by TCDD through AhR activation was detected at mRNA and protein levels. Induced TH protein was functional and its expression increased dopamine synthesis. The reporter gene assay and EMSA indicated that AhR directly regulated TH gene expression. Regulatory sequence called aryl hydrocarbon receptor responsive element III (AHRE-III was identified upstream of the TH gene from -285 bp to -167 bp. Under TCDD exposure, an AhR complex was bound to AHRE-III as well as the xenobiotic response element (XRE, though AHRE-III was not identical to XRE, the conventional AhR-binding motif. Conclusion Our results suggest TCDD directly regulate the dopamine system by TH gene transactivation via an AhR-AHRE-III-mediated pathway. The AhR- mediated pathway could have a particular AhR-mediated genomic control pathway transmitting the effects of TCDD action to target cells in the development of dopaminergic disabilities.

Akahoshi Eiichi

2009-06-01

456

Direct oxidative coupling of enamides and 1,3-dicarbonyl compounds: a facile and versatile approach to dihydrofurans, furans, pyrroles, and dicarbonyl enamides.  

Science.gov (United States)

An efficient manganese(III)-mediated oxidative coupling reaction between ?-aryl enamides and 1,3-dicarbonyl compounds has been developed. A series of dihydrofurans and dicarbonyl enamides were synthesized in moderate to good yields. Moreover, these dihydrofurans could be readily transformed into the corresponding furans and pyrroles via the Paal-Knorr reaction. PMID:25369562

Li, Pan; Zhao, Jingjing; Xia, Chungu; Li, Fuwei

2014-11-21

457

A heterogeneous nickel catalyst for the hydrogenolysis of aryl ethers without arene hydrogenation.  

Science.gov (United States)

A heterogeneous nickel catalyst for the selective hydrogenolysis of aryl ethers to arenes and alcohols generated without an added dative ligand is described. The catalyst is formed in situ from the well-defined soluble nickel precursor Ni(COD)(2) or Ni(CH(2)TMS)(2)(TMEDA) in the presence of a base additive, such as (t)BuONa. The catalyst selectively cleaves C(Ar)-O bonds in aryl ether models of lignin without hydrogenation of aromatic rings, and it operates at loadings down to 0.25 mol % at 1 bar of H(2) pressure. The selectivity of this catalyst for electronically varied aryl ethers differs from that of the homogeneous catalyst reported previously, implying that the two catalysts are distinct from each other. PMID:23163756

Sergeev, Alexey G; Webb, Jonathan D; Hartwig, John F

2012-12-19

458

Controlling the oxidative addition of aryl halides to Au(I).  

Science.gov (United States)

By means of density functional theory calculations, we computationally analyze the physical factors governing the oxidative addition of aryl halides to gold(I) complexes. Using the activation strain model of chemical reactivity, it is found that the strain energy associated with the bending of the gold(I) complex plays a key role in controlling the activation barrier of the process. A systematic study on how the reaction barrier depends on the nature of the aryl halide, ligand, and counteranion allows us to identify the best combination of gold(I) complex and aryl halide to achieve a feasible (i.e., low barrier) oxidative addition to gold(I), a process considered as kinetically sluggish so far. PMID:25263428

Fernndez, Israel; Wolters, Lando P; Bickelhaupt, F Matthias

2014-11-01

459

Photorefractive properties of bifunctional N-arylated carbazole derivatives in a carbazole polymer host matrix  

Science.gov (United States)

We report on the synthesis and the molecular properties of new N-arylated carbazole derivatives that are used as bifunctional chromophores in photorefractive (PR) polymer composites. The C-N bond of the N-aryl carbazole chromophore was formed directly by a nucleophilic aromatic substitution and Ullmann type coupling of carbazole with aryl halides. We performed calculations on the molecular conformation, the magnitude of the dipole moment and the linear polarizability tensor and their relative orientation. The PR performance of the chromophores, doped in an inert polymer host matrix and in a carbazole matrix, with C 60 as sensitizer, was evaluated using four-wave mixing experiments and photoconductivity measurements at 680 nm. The impact of the relative orientation of dipole moment and polarizability tensor on the Figure-Of-Merit (FOM) of photorefractive experiments was clearly demonstrated.

Schaerlaekens, M.; Hendrickx, E.; Hameurlaine, A.; Dehaen, W.; Persoons, A.

2002-03-01

460

Palladium-catalyzed aryl C-H olefination with unactivated, aliphatic alkenes.  

Science.gov (United States)

Palladium-catalyzed coupling between aryl halides and alkenes (Mizoroki-Heck reaction) is one of the most popular reactions for synthesizing complex organic molecules. The limited availability, problematic synthesis, and higher cost of aryl halide precursors (or their equivalents) have encouraged exploration of direct olefination of aryl carbon-hydrogen (C-H) bonds (Fujiwara-Moritani reaction). Despite significant progress, the restricted substrate scope, in particular noncompliance of unactivated aliphatic olefins, has discouraged the use of this greener alternative. Overcoming this serious limitation, we report here a palladium-catalyzed chelation-assisted ortho C-H bond olefination of phenylacetic acid derivatives with unactivated, aliphatic alkenes in good to excellent yields with high regio- and stereoselectivities. The versatility of this operationally simple method has been demonstrated through drug diversification and sequential C-H olefination for synthesizing divinylbenzene derivatives. PMID:25188679

Deb, Arghya; Bag, Sukdev; Kancherla, Rajesh; Maiti, Debabrata

2014-10-01

461

Merging photoredox with nickel catalysis: Coupling of ?-carboxyl sp3-carbons with aryl halides  

Science.gov (United States)

Over the past 40 years, transition metal catalysis has enabled bond formation between aryl and olefinic (sp2) carbons in a selective and predictable manner with high functional group tolerance. Couplings involving alkyl (sp3) carbons have proven more challenging. Here, we demonstrate that the synergistic combination of photoredox catalysis and nickel catalysis provides an alternative cross-coupling paradigm, in which simple and readily available organic molecules can be systematically used as coupling partners. By using this photoredox-metal catalysis approach, we have achieved a direct decarboxylative sp3sp2 cross-coupling of amino acids, as well as ?-O or phenyl-substituted carboxylic acids, with aryl halides. Moreover, this mode of catalysis can be applied to direct cross-coupling of Csp3H in dimethylaniline with aryl halides via CH functionalization. PMID:24903563

Zuo, Zhiwei; Ahneman, Derek T.; Chu, Lingling; Terrett, Jack A.; Doyle, Abigail G.; MacMillan, David W. C.

2015-01-01

462

Pd-catalyzed Heck reactions of aryl bromides with 1,2-diarylethenes  

Energy Technology Data Exchange (ETDEWEB)

A catalytic system composed of Pd(OAc){sub 2} and P(o-tol){sub 3} was found to be effective for the Heck reaction of aryl bromides with diarylethylenes. Using K{sub 2}CO{sub 3} as a base and DMF as a solvent, trisubstituted olefins were obtained in good to excellent yields. Aryl bromides containing an electron-withdrawing group in para position were less reactive for the Heck coupling reaction and gave substantial amount of homocoupling by-product suggesting that oxidative addition is not the rate-determining step. Electron withdrawing group substituent in the para position of stilbene affects the regioselectivity of the reaction. In this case, the phenyl group from the Ph-Pd complex migrates preferentially to the same carbon of the double bond to which the phenyl is bonded. Finally, a one pot sequential double Heck arylation of styrene was performed, giving trisubstituted olefin with an overall yield of 73%. (author)

Limberger, Jones; Poersch, Silvia; Monteiro, Adriano L., E-mail: adriano.monteiro@ufrgs.b [Universidade Federal do Rio Grande do Sul (LCM/UFRGS), Porto Alegre, RS (Brazil). Lab. of Molecular Catalysis

2011-07-01

463

Pd-catalyzed Heck reactions of aryl bromides with 1,2-diarylethenes  

International Nuclear Information System (INIS)

A catalytic system composed of Pd(OAc)2 and P(o-tol)3 was found to be effective for the Heck reaction of aryl bromides with diarylethylenes. Using K2CO3 as a base and DMF as a solvent, trisubstituted olefins were obtained in good to excellent yields. Aryl bromides containing an electron-withdrawing group in para position were less reactive for the Heck coupling reaction and gave substantial amount of homocoupling by-product suggesting that oxidative addition is not the rate-determining step. Electron withdrawing group substituent in the para position of stilbene affects the regioselectivity of the reaction. In this case, the phenyl group from the Ph-Pd complex migrates preferentially to the same carbon of the double bond to which the phenyl is bonded. Finally, a one pot sequential double Heck arylation of styrene was performed, giving trisubstituted olefin with an overall yield of 73%. (author)

464

Enhanced interfacial properties of carbon fiber composites via aryl diazonium reaction on water  

Science.gov (United States)

Polyacrylonitrile-based carbon fibers were functionalized with phenyl amine group via aryl diazonium reaction on water to improve their interfacial bonding with resin matrix. Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were employed to characterize ordered degree, functional groups, chemical states and morphology of carbon fiber surface, respectively. The results showed that phenyl amine groups were grafted on the fiber surface successfully. Mechanical property test results indicated that the aryl diazonium reaction in this paper could improve the interfacial shear strength by 73%, while the tensile strength was down very slightly. Hence aryl diazonium reaction on water could be a facile green platform to functionalize carbon fibers for many interesting applications.

Wang, Yuwei; Meng, Linghui; Fan, Liquan; Ma, Lichun; Qi, Meiwei; Yu, Jiali; Huang, Yudong

2014-10-01

465

N-aryl pyrrolo-tetrathiafulvalene based ligands: synthesis and metal coordination.  

Science.gov (United States)

A straightforward general synthetic access to N-aryl-1,3-dithiolo[4,5-c]pyrrole-2-thione derivatives 6 from acetylenedicarbaldehyde monoacetal is depicted. In addition to their potentiality as precursors to dithioalkyl-pyrrole derivatives, thiones 6 are key building blocks to N-aryl monopyrrolo-tetrathiafulvalene (MPTTF) derivatives 10. X-ray structures of four of these thiones intermediates, reminiscent of the corresponding MPTTF derivatives, are provided. When the aryl group is a binding pyridyl unit, the MPTTF derivative 10a can coordinate M(II) salts (M = Pt, Pd). The first examples of metal-directed orthogonal MPTTF-based dimers 11-14, obtained through coordination of 10a to cis-blocked square planar Pt or Pd complexes are described. Studies on the parameters influencing the dimer construction are presented, as well as first recognition properties of the resulting electron-rich clip for C(60). PMID:20143799

Balandier, Jean-Yves; Chas, Marcos; Dron, Paul I; Goeb, Sbastien; Canevet, David; Belyasmine, Ahmed; Allain, Magali; Sall, Marc

2010-03-01

466

State-dependent global and local electrophilicity of the aryl cations.  

Science.gov (United States)

Two alternative approachesvertical and adiabaticare used to estimate global and local electrophilicity (? and ?k+) indexes for a series of aryl cations in both the ground and first excited electronic states using the well-known Parr scheme. The energy parameters used in these methods are obtained by the B3LYP/6-311++G(2d,2p) calculations of the aryl cations and of their oxidized and reduced forms in acetonitrile medium. The ground state ? values are lower than those for the excited state, which is in accord with the maximum hardness principle. Analysis of the ? indexes calculated with more reliable adiabatic approach reveals a dependence of the ground and first excited state ? indexes on the singlettriplet energy gap of the aryl cations. A plot of the above dependence has a hyperbola-like shape; thus, the maximum (ground state) and minimum (first excited state) ? indexes correspond to the aryl cation, for which the singlettriplet splitting is close to zero. Moreover, the ?k+ index distribution at the ipso-carbon atoms does not obey the maximum hardness principle, since it depends on spin multiplicity, not on the electronic state spatial type. For many singlet ground state aryl cations, the ?k+ indexes at the ipso-carbon atom are lower when calculated in the excited triplet state; that is due to a strong ? delocalization onto two electrophilic centers. This explains a higher chemoselectivity of the triplet aryl cations in reactions with the ?-nucleophiles compared to the corresponding singlet arylium species. Applicability of the adiabatic approach for calculation of the ? and ?k+ indexes is supported by the experimental data on the nucleophile-independent parameter E for the singlet and triplet state of the p-Me2NC6H4+ cation. PMID:24712741

Bondarchuk, Sergey V; Minaev, Boris F

2014-05-01

467

Synthesis, structure and properties of compounds with chalcogen-nitrogen bond  

International Nuclear Information System (INIS)

Using the methods of IR, UV and 19F NMR spectroscopy the structure of synthesized diaryl-N-trifluoroacetyl tellurium imides is studied. It is shown that these compounds due to considerable degree of binary bond in the nitrogen-carbon bond can coexist in the form of syn- and anti-isomers. Electron donor substituents in aryl nuclei induce the change of the positive charge on tellurium atom, as a result, the relative stability of two forms also changes

468