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1

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

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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

Synthesis and Monoamine Oxidase Inhibitory Activities of some 3-(4-Fluorophenyl)-5-aryl-N-substituted-4,5-dihydro-(1H)-pyrazole-1-carbothioamide Derivatives.  

Science.gov (United States)

28 new 3-(4-fluorophenyl)-5-aryl-N-substituted-4,5-dihydro-1H-pyrazole-1-carbothioamide derivatives were synthesized and evaluated in vitro for their monoamine oxidase (MAO) A and B inhibitory activity and selectivity. The derivatives substituted by halogen on the fifth position of pyrazole ring, inhibited MAO-A enzyme with a high selectivity index. On the other hand, compounds substituted with 2-naphthyl inhibited MAO-B enzyme with a moderate selectivity index. Docking studies were done to highlight the interactions of the most active derivative with the active site of MAO-A. In addition, in vivo antidepressant and anxiolytic activities of the compounds having selective MAO-A inhibitory effects, were investigated by using Porsolt forced swimming and elevated plus-maze tests respectively. 3-(4-Fluorophenyl)-5-(4-chloro-phenyl)-N-allyl-4,5-dihydro-1H-pyrazole-1-carbothio-amide has antidepressant, 3-(4-fluorophenyl)-5-(4-chlorophenyl)-N-methyl-4,5-dihydro-1H-pyrazole-1-carbothioamide and 3-(4-fluoro-phenyl)-5-(4-bromophenyl)-N-ethyl-4,5-dihydro-1H-pyrazole-1-carbothioamide have anxiolytic activity. PMID:24452523

Koç, G S; Tan, O U; Uçar, G; Y?ld?r?m, E; Erol, K; Palaska, E

2014-11-01

3

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

Science.gov (United States)

Discovering dopamine D2-like receptor subtype-selective ligands has been a focus of significant investigation. The D2R-selective antagonist 3-[4-(4-chlorophenyl)-4-hydroxypiperidinyl]methylindole (1, L741,626; Ki(D2R/D3R) = 11.2:163 nM) has previously provided a lead template for chemical modification. Herein, analogues have been synthesized where the piperidine was replaced by a tropane ring that reversed the selectivity seen in the parent compound, in human hD2LR- or hD3R-transfected HEK 293 cells (31, Ki(D2R/D3R) = 33.4: 15.5 nM). Further exploration of both N-substituted and aryl ring-substituted analogues resulted in the discovery of several high affinity D2R/D3R ligands with 3-benzofurylmethyl-substituents (e.g., 45, Ki(D2R/D3R) = 1.7:0.34 nM) that induced high affinity not achieved in similarly N-substituted piperidine analogues and significantly (470-fold) improved D3R binding affinity compared to the parent ligand 1. X-ray crystallographic data revealed a distinctive spatial arrangement of pharmacophoric elements in the piperidinol vs tropine analogues, providing clues for the diversity in SAR at the D2 and D3 receptor subtypes. PMID:18774793

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

2011-01-01

4

Structure-activity relationships for a novel series of dopamine D2-like receptor ligands based on N-substituted 3-aryl-8-azabicyclo[3.2.1]octan-3-ol.  

Science.gov (United States)

Discovering dopamine D2-like receptor subtype-selective ligands has been a focus of significant investigation. The D2R-selective antagonist 3-[4-(4-chlorophenyl)-4-hydroxypiperidinyl]methylindole (1, L741,626; K(i)(D2R/D3R) = 11.2:163 nM) has previously provided a lead template for chemical modification. Herein, analogues have been synthesized where the piperidine was replaced by a tropane ring that reversed the selectivity seen in the parent compound, in human hD2(L)R- or hD3R-transfected HEK 293 cells (31, K(i)(D2R/D3R) = 33.4:15.5 nM). Further exploration of both N-substituted and aryl ring-substituted analogues resulted in the discovery of several high affinity D2R/D3R ligands with 3-benzofurylmethyl-substituents (e.g., 45, K(i)(D2R/D3R) = 1.7:0.34 nM) that induced high affinity not achieved in similarly N-substituted piperidine analogues and significantly (470-fold) improved D3R binding affinity compared to the parent ligand 1. X-ray crystallographic data revealed a distinctive spatial arrangement of pharmacophoric elements in the piperidinol vs tropine analogues, providing clues for the diversity in SAR at the D2 and D3 receptor subtypes. PMID:18774793

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

2008-10-01

5

Hemoglobin adducts of N-substituted aryl compounds in exposure control and risk assessment.  

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Arylamines, nitroarenes, and azo dyes yield a common type of metabolite, the nitroarene, which produces a hydrolyzable adduct with protein and is closely related to the critical, ultimate toxic and genotoxic metabolite. The target dose as measured by hemoglobin adducts in erythrocytes reflects not only the actual uptake from the environment but also an individual's capacity for metabolic activation and is therefore an improved dosimeter for human exposure. The usefulness of hemoglobin adducts...

Neumann, H. G.; Birner, G.; Kowallik, P.; Schu?tze, D.; Zwirner-baier, I.

1993-01-01

6

Heavy Grignard reagents: challenges and possibilities of aryl alkaline earth metal compounds.  

Science.gov (United States)

Compounds of the type aryl--M--X, with M=Ca, Sr, Ba and X as any kind of ligand (such as halide, phosphanide, amide, aryl), are presented. The low reactivity of the heavy alkaline earth metals calcium, strontium, and barium enforces an activation prior to use for the direct synthesis. The insertion of these metals into C--I bonds of aryl iodides (direct synthesis) yields aryl metal iodides and has to be performed at low temperatures and in THF. Aryl alkaline-earth-metal compounds show some characteristics: 1) the ease of ether cleavage enforces low reaction temperatures, 2) for Sr and Ba the Schlenk equilibrium is shifted towards homoleptic MI2 and MPh2, 3) high solubility of diaryl alkaline-earth-metal derivatives in THF even at low temperatures initiated quantum chemical investigations on the aggregation behavior, and 4) a strong low field shift of the 13C resonances of the ipso carbon atoms in NMR spectra was observed. First results from quantum chemical calculations on diaryl dicalcium(I) suggest a long Ca--Ca bond with a considerable Ca--Ca bond dissociation energy. Initial results on a selection of applications such as metallation, metathesis, and addition reactions of aryl calcium compounds are presented as well. PMID:17577250

Westerhausen, Matthias; Gärtner, Martin; Fischer, Reinald; Langer, Jens; Yu, Lian; Reiher, Markus

2007-01-01

7

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)

8

Impact of restricted mass transport on pyrolysis pathways for aryl ether containing lignin model compounds  

Energy Technology Data Exchange (ETDEWEB)

Pyrolysis studies have been conducted at 375{degree}C on several silica-immobilized phenethyl phenyl ether (PPE) model compounds, representative of related {beta}-O-4 aryl ether linkages in lignin, to explore the impact of restricted mass transport on reaction pathways. As found previously for fluid-phase PPE, two competitive free-radical decay pathways are operative including a significant rearrangement pathway involving an O,C-phenyl shift for surface-attached PhCH{sub 2}CH{center_dot}OPh radicals. The selectivity for the rearrangement pathway is found to be sensitive to substituent and, in particular, to the structure of neighbouring spacer molecules on the surface. In contrast to solution-phase behavior, dilution of PPE molecules on the surface with rigid aromatic spacers such as biphenyl or naphthalene hinder the rearrangement path. This phenomenon, attributed to steric constraints that decrease the rate of the 1,2-phenyl shift, is not observed when a more flexible spacer molecule (diphenylmethane) is employed. An improved knowledge of the pathways involved is important since this rearrangement pathway, which was also observed in the pyrolysis of {alpha}-aryl ether models, can result in the formation of valuable chemicals (aryl aldehydes and ketones) or undesirable refractory compounds (biphenyls and diphenylmethanes) during the thermochemical processing of lignin. 36 refs., 2 figs., 1 tab., Scheme 8.

Britt, P.F.; Buchanan, A.C. III; Malcolm, E.A. [Oak Ridge National Laboratory, Oak Ridge, TN (USA). Chemical & Analytical Sciences Division

2000-12-01

9

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2008-01-01

10

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 Buchwald–Hartwig-type reactions, copper-mediated Ullmann-type and Chan–Lam-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 Chan–Lam reactions. Chan–Lam 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 Buchwald–Hartwig-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 C–N bond formation in the course of a total synthesis or drug synthesis.

Burkhard Koenig

2011-01-01

11

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

Science.gov (United States)

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 Buchwald-Hartwig-type reactions, copper-mediated Ullmann-type and Chan-Lam-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 Chan-Lam reactions. Chan-Lam 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 Buchwald-Hartwig-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 C-N bond formation in the course of a total synthesis or drug synthesis. PMID:21286396

Fischer, Carolin; Koenig, Burkhard

2011-01-01

12

Aqueous high-temperature chemistry of carbo- and heterocycles. 29. Reactions of aryl hydrocarbons, aryl N-oxides and aryl carbonyl compounds in supercritical water at 460{degree}C  

Energy Technology Data Exchange (ETDEWEB)

A series of aryl hydrocarbons, aryl N-oxides, and aryl carbonyl compounds were subjected to thermolysis at 460{degree}C in water alone, in 15% aqueous formic acid, in 15% aqueous sodium formate, and, for comparison of purely thermal reactions, in cyclohexane. The runs were carried out initially for 7 min and, in most cases, also for 1 h. The aryl carbonyl substrates underwent mainly carbonyl reduction mainly under reduction conditions, with ring opening only observed in significant amounts for 1,4-naphthoquinone and 3,4-benzocoumarin. The arenes produced mainly reduction products with only low yields of ring-opened products observed. Aryl oximes underwent significant denitrogenation and subsequent reduction with only very little cleavage to simpler aromatic systems. The N-oxides underwent deoxygenation, and in the case of isoquinoline, ring opening of the heterocyclce was prevalent. 2-Aminobiphenyl was denitrogenated and cleaved to simpler systems in cyclohexane, but in the aqueous systems it underwent mainly cyclization to yield carbazole with only low yields of denitrogenated products. 2-Phenylphenol was unreactive under aqueous conditions with only low yields of deoxygenated products observed. 11 refs., 15 figs., 1 tab.

Katritzky, A.R.; Ignatchenko, E.S.; Allin, S.M.; Barcock, R.A.; Siskin, M.; Hudson, C.W. [University of Florida, Gainesville, FL (United States). Center for Heterocyclic Compounds, Dept. of Chemistry

1997-01-01

13

Synthesis and fungicidal activity of some sulphide derivatives of O-phenyl-N-substituted phenylcarbamates  

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Monosulphides of O-phenyl-N-substituted phenylcar- bamates were prepared by the reaction between O- phenyl-N-substituted phenylcarbamates and sulph- ur dichloride while the corresponding disulphides were prepared by the reaction between O-phenyl-N- substituted phenylcarbamates and sulphur monoch- loride. The synthesized compounds were characte-rized by elemental analysis, thin layer chromatogra-phy (TLC), Fourier-transform infrared, 1H and 13C nuclear magnetic resonance spectroscopic techniqu...

Adelowo, F. E.; Ojo, I. A. O.; Amuda, O. S.

2011-01-01

14

Synthesis of positron labeled photoactive compounds: 18F labeled aryl azides for positron labeling of biochemical molecules  

International Nuclear Information System (INIS)

The authors have prepared various [18F] fluorine labeled aryl azides as a novel photoactive compounds suitable for positron labeling of biochemical molecules. The introduction of fluorine substituents to aryl azides can be expected to have dramatic effects on their nature and reactivity toward photolysis. Positron labeled reagents for labeling proteins or peptides have recently attracted considerable attention due to their wide applicability in biochemistry and positron emission tomography (PET). Various labeled azide compounds are often used in biochemistry for radiolabeling biological molecules by photolysis, but there have been no reports on the preparation or use of fluorine-18 labeled azides. The authors now report a novel synthesis of 18F-labeled aryl azides which will have wide application in the biochemistry and nuclear medicine as a means for 18F-fluorine labeling for proteins, peptides, and nucleic acids. 2 tabs

15

Synthesis of positron labeled photoactive compounds: {sup 18}F labeled aryl azides for positron labeling of biochemical molecules  

Energy Technology Data Exchange (ETDEWEB)

The authors have prepared various [{sup 18}F] fluorine labeled aryl azides as a novel photoactive compounds suitable for positron labeling of biochemical molecules. The introduction of fluorine substituents to aryl azides can be expected to have dramatic effects on their nature and reactivity toward photolysis. Positron labeled reagents for labeling proteins or peptides have recently attracted considerable attention due to their wide applicability in biochemistry and positron emission tomography (PET). Various labeled azide compounds are often used in biochemistry for radiolabeling biological molecules by photolysis, but there have been no reports on the preparation or use of fluorine-18 labeled azides. The authors now report a novel synthesis of {sup 18}F-labeled aryl azides which will have wide application in the biochemistry and nuclear medicine as a means for {sup 18}F-fluorine labeling for proteins, peptides, and nucleic acids. 2 tabs.

Hashizume, Kazunari; Hashimoto, Naota; Miyake, Yoshihiro [Institute for Biofunctional Research, Osaka (Japan)

1995-10-20

16

Mesomorphic behaviour of N-benzoyl-N?-aryl thioureas liquid crystalline compounds  

Science.gov (United States)

A series of N-benzoyl- N'-aryl thiourea derivatives bearing alkoxy groups in terminal positions have been prepared and investigated for their potential liquid crystals properties. It was found that only the compounds which have only two alkoxy chains show calamitic mesomorphic behaviour, with nematic, smectic A and C phases being displayed. The type and stability of these mesophases are greatly influenced by the alkyl chain length. Successive introduction of additional alkoxy groups on the benzoyl moiety led to a significant decrease of the clearing points and suppression of the mesogenic character. Using of branched alkyl chain, 2-ethyl-hexyl, instead of normal alkyl group, led to the disappearance of mesogenic behaviour together with the lowering of the clearing temperature. The influence of chain length and number of chains is discussed.

Ili?, Monica; Bucos, Madalina; Dumitra?cu, Florea; Cîrcu, Viorel

2011-02-01

17

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

18

Direct synthesis of high-valent aryl-Cu(II) and aryl-Cu(III) compounds: mechanistic insight into arene C-H bond metalation.  

Science.gov (United States)

Copper and its salts are abundant, inexpensive, and eco-friendly and have been used as the surrogates of noble metals to effect arene C-H bond activation and transformations. Despite of the recent significant progress of the study, syntheses of high-valent arylcopper(II-III) compounds are still very rare and mechanisms of copper(II)-catalyzed reactions remain elusive. With the use of azacalix[1]arene[3]pyridines as a platform, a number of arylcopper(II) compounds were synthesized efficiently from the reaction of Cu(ClO4)2 under ambient conditions. The resulting aryl-Cu(II) compounds, which contain an unprecedented (substituted) phenyl-Cu(II) ?-bond, were stable under atmospheric conditions and can undergo facile oxidation reaction by free copper(II) ions or oxone to afford arylcopper(III) compounds in good yields. Both arylcopper(II) and arylcopper(III) compounds were characterized unambiguously by means of XRD, XPS, and NMR methods. Experimental evidence including reaction kinetics, LFER and KIE, and theoretical calculations indicated that the Cu(ClO4)2-mediated arene C-H bond activation proceeds plausibly through an electrophilic aromatic metalation pathway. The synthesis of high-valent arylcopper compounds and the reaction mechanism reported here highlight the diversity and richness of organocopper chemistry. PMID:24730979

Zhang, Hu; Yao, Bo; Zhao, Liang; Wang, De-Xian; Xu, Bo-Qing; Wang, Mei-Xiang

2014-04-30

19

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

International Nuclear Information System (INIS)

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

20

Study using 1 H and 13 V NMR of 3-aryl-s-triazole benzoate azole type compounds and intermediaries  

International Nuclear Information System (INIS)

Approximately 62% of the compounds used for medical purposes are heterocyclic, and are distributed as follows: 95% containing hydrogen, 28% containing sulfur and 18% containing oxygen in the structural composition. Some triazole-s-triazole type hetero aromatic systems and intermediaries, such as 1-aryl hydrazides exhibited bactericide, anti inflammatory and fungi stat activities. All the triazoles are are obtained synthetically, and are not found in the Nature. The proton and carbon-13 spectra of the non usual I, II and III compounds that we obtained are discussed in this work

 
 
 
 
21

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 in vivo. 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

22

Synthesis and Fungicidal activity of some sulphide derivatives of O-Ethyl-N-substituted phenylcarbamates  

International Nuclear Information System (INIS)

Monosulphides of O-ethyl-N-substituted phenylcarbamates were prepared by the reaction between O-ethyl-N-substituted phenylcarbamates and sulphur dichloride, while the corresponding disulphides were prepared by the reaction between O-ethyl-N-substituted phenylcarbamates and sulphur monochloride. The synthesized compounds were characterized by elemental analysis, thin layer chromatography (TLC), Fourier-transform infrared, and /sup 1/H and /sup 13/C nuclear magnetic resonance spectroscopic techniques. In vitro fungicidal assay of these sulphides against Fusarium oxysporum, Aspergillus niger, Aspergillus flavus and Rhizopus stolonifer showed that they had Greater fungicidal activity than their parent carbamates. The synthesized sulphides were more active towards A. Niger and A. flavus. Unlike the parent carbamates, the type of substituents attached to the aromatic nucleus of these sulphides had little or no effect on their fungicidal activity as there was insignificant variation in the fungicidal activity of the monosulphide and the disulphide derivatives of O-ethyl-N-substituted phenylcarbamates. (author)

23

Synthesis and fungicidal activity of some sulphide derivatives of O-phenyl-N-substituted phenylcarbamates  

Directory of Open Access Journals (Sweden)

Full Text Available Monosulphides of O-phenyl-N-substituted phenylcar- bamates were prepared by the reaction between O- phenyl-N-substituted phenylcarbamates and sulph- ur dichloride while the corresponding disulphides were prepared by the reaction between O-phenyl-N- substituted phenylcarbamates and sulphur monoch- loride. The synthesized compounds were characte-rized by elemental analysis, thin layer chromatogra-phy (TLC, Fourier-transform infrared, 1H and 13C nuclear magnetic resonance spectroscopic techniques. In vitro fungicidal assay of these sulphides against Fusarium oxysporum, Aspergillus niger, Aspergillus flavus and Rhizopus stolonifer showed that they were more fungicidal than their parent carbamates. The synthesized sulphides were more active towards As-pergillus niger and Aspergillus flavus. There was little or no variations in the fungicidal activities of the synthesized monosulphides and disulphides of O-phen- yl-N-substituted phenyl carbamates.

F. E. Adelowo

2011-11-01

24

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

25

Alkylation of N-substituted 2-phenylacetamides  

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

SLOBODAN D. PETROVIC

2004-10-01

26

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

27

Amine-synthesizing enzyme N-substituted formamide deformylase: Screening, purification, characterization, and gene cloning  

Science.gov (United States)

N-substituted formamide was produced through the hydration of an isonitrile by isonitrile hydratase in the isonitrile metabolism. The former compound was further degraded by a microorganism, strain F164, which was isolated from soil through an acclimatization culture. The N-substituted formamide-degrading microorganism was identified as Arthrobacter pascens. The microbial degradation was found to proceed through an enzymatic reaction, the N-substituted formamide being hydrolyzed to yield the corresponding amine and formate. The enzyme, designated as N-substituted formamide deformylase (NfdA), was purified and characterized. The native enzyme had a molecular mass of ?61 kDa and consisted of two identical subunits. It stoichiometrically catalyzed the hydrolysis of N-benzylformamide (an N-substituted formamide) to benzylamine and formate. Of all of the N-substituted formamides tested, N-benzylformamide was the most suitable substrate for the enzyme. However, no amides were accepted as substrates. The gene (nfdA) encoding this enzyme was also cloned. The deduced amino acid sequence of nfdA exhibited the highest overall sequence identity (28%) with those of regulatory proteins among known proteins. Only the N-terminal region (residues 58–72) of NfdA also showed significant sequence identity (27–73%) to that of each member of the amidohydrolase superfamily, although there was no similarity in the overall sequence except in the above limited region. PMID:15358859

Fukatsu, Hiroshi; Hashimoto, Yoshiteru; Goda, Masahiko; Higashibata, Hiroki; Kobayashi, Michihiko

2004-01-01

28

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

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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

29

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

Science.gov (United States)

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. PMID:25325155

Steenackers, Hans; Dubey, Akanksha; Robijns, Stijn; Ermolat'ev, Denis; Delattin, Nicolas; Dovgan, Barbara; Girandon, Lenart; Fröhlich, Mirjam; De Brucker, Katrijn; Cammue, Bruno P A; Thevissen, Karin; Balzarini, Jan; Van der Eycken, Erik V; Vanderleyden, Jozef

2014-01-01

30

Biotransformation and biodegradation of N-substituted aromatics in methanogenic granular sludge.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Razo Flores, E.

1997-01-01

31

Synthesis and oxidation by xanthine oxidase from Arthrobacter M-4 of 6-aryl-4(3H)-pteridinones and related compounds.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this thesis xanthine oxidase from Arthrobacter M-4 in the form of a cell-free extract or as immobilized cells has been studied with regard to its application In preparative organic chemistry. The enzyme has a broad substrate specificity towards azaheterocycles as purines and pteridines.The unequivocal preparation of 6-aryl-4(3H)-pteridinones and 7-aryl-4(3H)- pteridinones with different substituents at the para position of the phenyl group is described. The oxidation of these compounds by ...

Meester, J. W. G.

1987-01-01

32

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

33

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

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

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

1980-01-01

34

Biotransformation and biodegradation of N-substituted aromatics in methanogenic granular sludge.  

Science.gov (United States)

N-Substituted aromatic compounds are environmental contaminants associated with the production and use of dyes, explosives, pesticides and pharmaceuticals. In this article, we examine the potential of anaerobic granular sludge from anaerobic treatment systems towards the detoxification, transformation, and mineralization of nitroaromatic and azo compounds. Nitroaromatics and azo dyes with strong electron withdrawing are highly inhibitory to acetoclastic methanogenic bacteria. However, nitro and azo substituted aromatics are readily reductively detoxified in methanogenic consortia to their respective aromatic amines, which are several orders of magnitude less toxic. This reductive detoxification has allowed the successful operation of anaerobic reactors for the treatment of highly toxic aromatic compounds. In the course of the experiments it was discovered that some aromatic amines were mineralized. These results indicate that some N-substituted aromatic compounds can be completely mineralized and serve as a carbon and energy source for anaerobic bacteria. PMID:9340000

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

1997-07-01

35

Lewis acid free high speed synthesis of nimesulide-based novel N-substituted cyclic imides  

International Nuclear Information System (INIS)

The first synthesis of nimesulide-based novel cyclic imides has been accomplished via the reaction of an amine prepared from nimesulide with appropriate anhydrides in the presence of sodium acetate. Using this process a variety of N-substituted cyclic imides was prepared in good yields in glacial acetic acid. Some of the compounds synthesized showed anti-inflammatory activities when tested in vivo. (author)

36

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...2-propenyl)-N-(substituted phenyl) acetamide. (a) Chemical substances...2-propenyl)-N -(substituted phenyl) acetamide (P-83-1085) is...

2010-07-01

37

Indium(III)-catalyzed synthesis of N-substituted pyrroles under solvent-free conditions  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Vários pirróis N-substituídos foram sintetizados pela reação de ?-dicetonas (R¹C(O)CH2CH2C(O)R²: R¹, R² = Me, Ph) com aminas (RNH2: R = Alkyl, Aryl, TsNH) ou diaminas (1,6-diaminohexano and 1,2-diaminoetano) na presença de tribrometo de índio, tricloreto de índio ou trifluorometanossulfonato de índi [...] o a temperatura ambiente e sem solventes. O protocolo envolve operações simples e os produtos são isolados em excelentes rendimentos (81-98%). Abstract in english A variety of N-substituted pyrroles have been synthesized by reacting ?-diketones (R¹C(O)CH2CH2C(O)R²: R¹, R² = Me, Ph) with amines (RNH2: R=Alkyl, Aryl, TsNH) or diamines (1,6-diaminohexane and 1,2-diaminoethane) in the presence of indium tribromide, indium trichloride or indium trifluoromethanesul [...] fonate at room temperature under solvent-free conditions. The experiment protocol features simple operations, and the products are isolated in high to excellent yields (81-98%).

Jiu-Xi, Chen; Miao-Chang, Liu; Xiao-Liang, Yang; Jin-Chang, Ding; Hua-Yue, Wu.

38

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

Directory of Open Access Journals (Sweden)

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

39

Synthesis and cytotoxic activity of N-substituted thiosemicarbazones of 3-(3,4-methylenedioxy)phenylpropanal.  

Science.gov (United States)

Five new N-substituted thiosemicarbazones of 3-(3,4-methylenedioxy)phenylpropanal were synthesized. Safrole, a natural product obtained from sassafras oil (Ocotea pretiosa), was oxidized to alcohol using BH3-THF and H2O2, followed by oxidation to aldehyde using pyridinium dichromate (PDC) and condensation with five N-substituted derivatives of thiosemicarbazide. Tests were performed to evaluate the cytotoxic activity with continuous chain KB cells (epidermoide carcinoma of the floor of the mouth). Compounds 5 and 6 showed IC50 values of 1.5 and 4.6 micrograms/ml, respectively. PMID:9639871

Joselice e Silva, M; Alves, A J; Do Nascimento, S C

1998-03-01

40

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

Science.gov (United States)

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

Shiino, M; Watanabe, Y; Umezawa, K

2001-05-01

 
 
 
 
41

Aromatic-hydroxyl interaction of an alpha-aryl ether lignin model-compound on SBA-15, present at pyrolysis temperatures.  

Science.gov (United States)

An aromatic alpha-aryl ether compound (a benzyl phenyl ether analogue) was covalently grafted to mesoporous silica SBA-15, to create BPEa-SBA-15. The BPEa-SBA-15 was subjected to successive heating cycles up to 600 °C, with in situ monitoring by DRIFTS. It was found that the toluene moiety coordinates to SBA-15 surface silanol hydroxyl groups via an aromatic-hydroxyl interaction. This interaction is evidenced by a red-shift of the aromatic C-H stretches, as well as a red-shift and broadening of the surface hydroxyl O-H stretches, which are features characteristic of a hydrogen bond. These features remain present during heating until ?400 °C whereupon the ether linkage of BPEa-SBA-15 is cleaved, accompanied by loss of the toluene moiety. PMID:25045863

Kandziolka, M V; Kidder, M K; Gill, L; Wu, Z; Savara, A

2014-10-21

42

[Influence of new N,N'-substituted piperazines on thrombin-induced platelet activation].  

Science.gov (United States)

We have studied the influence of new N,N'-substituted piperazines with variable nature of the linker between piperazine and aromatic cycles (carbonyl group in VR-0411 versus sulfonyl group in VR-0511) on thrombin-induced platelet aggregation, cytoplasmic Ca2+ mobilization in platelets, and P-selectin exposure on the platelet plasma membrane. The inhibitory effect of VR-0511 on platelet aggregation exceeds the effects of the reference compound aspirin and VR-0411 by 35 and 42%, respectively (p compounds on the mobilization of cytoplasmic Ca2+ in platelets and P-selectin exposure indicate that VR-0411 and VR-0511 inhibit platelet activation in these tests by 28 and 61%, (p < or = 0.01) and 34 and 58% (p < or = 0.01), respectively. The possible targets for VR-0411 and VR-0511 are thromboxane and inositol triphosphate-dependent (IP3 formation) pathways of activation signal transfer. PMID:25335388

Veselkina, O C; Petrishchev, N N; Vasina, L V; Borovitov, M E; Seliutin, A V; Chepanov, S V; Sel'kov, S A

2014-01-01

43

Synthesis of some N-substituted nitroimidazole derivatives as potential antioxidant and antifungal agents.  

Science.gov (United States)

Some new nitroimidazole derivatives have been synthesized by treating 4,5-dinitro- and 2-methyl-4,5-dinitroimidazoles with epoxypropane, epichlorohydrin or phenacyl bromide in alkylation reactions. The nitro group in N-substituted 4,5-dinitro- and 2-methyl-4,5-dinitroimidazoles has been replaced with primary and secondary amines to afford 4-amino-5-nitroimidazole derivatives. Some of the compounds have been tested for their antioxidant and antifungal properties against fungi species acting on timber. Nearly all of them have shown significant antioxidant activity in comparison with that of tocopherol, which is used as a reference substance. Two compounds from those tested have revealed very strong fungistatic activity against Sclerophoma pityophila. PMID:18590938

Olender, Dorota; Zwawiak, Justyna; Lukianchuk, Victor; Lesyk, Roman; Kropacz, Aleksandra; Fojutowski, Andrzej; Zaprutko, Lucjusz

2009-02-01

44

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

45

Investigation of various N-heterocyclic substituted piperazine versions of 5/ 7-{[2-(4-Aryl-piperazin-1-yl)-ethyl]-propyl-amino}-5,6,7,8-tetrahydro-naphthalen-2-ol: Effect on affinity and selectivity for dopamine D3 receptor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Here we report on the design and synthesis of several heterocyclic analogues belonging to the 5/ 7-{[2-(4-aryl-piperazin-1-yl)-ethyl]-propyl-amino}-5,6,7,8-tetrahydro-naphthalen-2-ol series of molecules. Compounds were subjected to [3H]spiperone binding assays, carried out with HEK-293 cells expressing either D2 or D3 dopamine receptors, in order to evaluate their inhibition constant (Ki) at these receptors. Results indicate that N-substitution on the piperazine ring can accommodate various s...

Brown, Dennis A.; Mishra, Manoj; Zhang, Suhong; Biswas, Swati; Parrington, Ingrid; Antonio, Tamara; Reith, Maarten E. A.; Dutta, Aloke K.

2009-01-01

46

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

47

Antifungal and cytotoxic activities of some N-substituted aniline derivatives bearing a hetaryl fragment.  

Science.gov (United States)

Diverse N-substituted anilines bearing hetaryl fragments were easily prepared from corresponding aldimines derived from commercially available aromatic aldehydes and anilines. 2-Furyl substituted anilines showed very good antifungal activities against dermatophytes, particularly against Trichophyton rubrum (MIC=3.12-6.25microg/mL). In addition, all active compounds, 45-47, 73, and 74, were tested for cytotoxic activities against breast (MCF-7), lung (H-460), and central nervous system (SF-268) human cancer cell lines with the NCI-anticancer-drug screen. The activity of amines described in this paper, along with the low toxicity of most of them, shows promise for the future development of non-toxic new antimycotic agents. PMID:17981473

Kouznetsov, Vladímir V; Vargas Méndez, Leonor Y; Sortino, Maximiliano; Vásquez, Yelkaira; Gupta, Mahabir P; Freile, Mónica; Enriz, Ricardo D; Zacchino, Susana A

2008-01-15

48

Synthesis and antibacterial activity of some novel N-substituted piperazinyl-quinolones.  

Science.gov (United States)

A series of N-substituted-piperazinyl-quinolones were synthesized and evaluated for in vitro antibacterial activity. Compounds with a 2-(2,4-dichlorophenyl)-2-oxoethyl group attached to the piperazine ring (5a-c) had similar antibacterial activity to the reference drugs, ciprofloxacin, norfloxacin and enoxacin against both Gram-positive and Gram-negative bacteria. The oximes 6a-c and 6g-i were almost less active than corresponding ketones against the tested microorganisms, however the 2,4-difluorophenyl analogues (6g-i) were more active than 2,4-dichlorophenyl derivatives (6a-c). If the hydrogen of oxime is replaced with a benzyl group (6d-f & 6j-l), in-vitro antibacterial activity was decreased against both Gram-positive and Gram-negative bacteria. Generally ciprofloxacin derivatives were more active than norfloxacin and enoxacin derivatives. PMID:11822230

Foroumadi, A; Davood, A; Mirzaei, M; Emami, S; Moshafi, M H

2001-01-01

49

Hydrazone- and hydrazide-containing N-substituted glycines as peptoid surrogates for expedited library synthesis: application to the preparation of Tsg101-directed HIV-1 budding antagonists.  

Science.gov (United States)

Replacing the Pro6 in the p6(Gag)-derived 9-mer "P-E-P-T-A-P-P-E-E" with N-substituted glycine (NSG) residues is problematic. However, incorporation of hydrazone amides ("peptoid hydrazones") can be readily achieved in library fashion. Furthermore, reduction of these hydrazones to N-substituted "peptoid hydrazides" affords a facile route to library diversification. This approach is demonstrated by application to Tsg101-binding compounds designed as potential HIV budding antagonists. [reaction: see text] PMID:17048869

Liu, Fa; Stephen, Andrew G; Adamson, Catherine S; Gousset, Karine; Aman, M Javad; Freed, Eric O; Fisher, Robert J; Burke, Terrence R

2006-10-26

50

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

Directory of Open Access Journals (Sweden)

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

Dr. S. M. Hipparagi

2010-05-01

51

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  

Directory of Open Access Journals (Sweden)

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

52

Assays of dioxins and dioxin-like compounds in actually contaminated soils using transgenic tobacco plants carrying a recombinant mouse aryl hydrocarbon receptor-mediated ?-glucuronidase reporter gene expression system  

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The transgenic tobacco plant XD4V-26 carrying the recombinant mouse aryl hydrocarbon receptor XD4V-mediated ?-glucuronidase (GUS) reporter gene expression system was used for assay of dioxins and dioxin-like compounds consisting of polychlorodibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls (Co-PCBs) in actually contaminated soils. The transgenic tobacco plant XD4V-26 showed a significant dose-dependent induced GUS activity when cultured on MS medium co...

Inui, Hideyuki; Gion, Keiko; Utani, Yasushi; Wakai, Taketo; Kodama, Susumu; Eun, Heesoo; Kim, Yun-seok; Ohkawa, Hideo

2012-01-01

53

Synthesis of sigma-aryl compounds of molybdenum, rhenium, ruthenium, and rhodium from the metal-metal bonded binuclear acetates of molybdenum(II), rhenium(III), ruthenium(II,III), and rhodium(II)  

International Nuclear Information System (INIS)

The interaction between diarylmagnesiums, MgAr2(Ar = C6H5, 2-MeOC6H4 and 4-FC6H4) and the metal-metal bonded binuclear bridged tetra-acetates, M2sup(II)(CO2Me)4, (M = Mo and Rh) and Rusup(II,III)(CO2Me)4Cl in the presence of trimethylphosphine produces monomeric (Ru,Rh) or dimeric (Mo)aryls; for Ru and the 2-methoxyphenyl, hydrogen loss from the MeO group leads to formation of a metallocycle. In the absence of PMe3, Re2(O2CMe)4Cl2 gives a dimeric binary aryl, Re2(2-MeOC6H4)6. The compounds have been studied by 1H, 31P, and 13C n.m.r. and i.r. spectroscopy. Likely structures are discussed. (author)

54

Synthesis and biological evaluation of N-substituted polycyclic imides derivatives.  

Science.gov (United States)

The preparation of 16 derivatives of 3,5,8-trioxo-4-azatricyclo- [5.2.2.0(2.6)]undec-1-yl acetate and 8 derivatives of 1-isobutoxy-4-azatricyclo[5.2.2.0(2.6)]undecane-3,5,8-trione was described. Substituents to the imide N-atom were alkyl-(aryl)piperazine fragments with an alkyl linker being propyl or butyl group. Selected newly obtained compounds were evaluated in vitro against anti-HIV-1 activity. A broad group o fderivatives were tested for their antibacterial and antifungal activity. The pharmacological properties of butyl derivatives of imide 6 were evaluated in three behavioral tests in mice. The molecular structures of starting polycyclic 6-acetyl-imides, 1 and 5, were determined by X-ray crystallography. Presented tests have not revealed any activity of the compounds, however, selected derivatives exerted no neurotoxicity in behavioral tests. PMID:24147359

Bielenica, Anna; Struga, Marta; Miros?aw, Barbara; Kozio?, Anna E; Kossakowski, Jerzy; Sanna, Giuseppina; La Colla, Paolo; Giliberti, Gabriele

2013-01-01

55

P-arylation: arynes to aryl-phosphonates, -phosphinates, and -phosphine oxides.  

Science.gov (United States)

Synthesis of organo-phosphorus compounds and their application in organic synthesis and life sciences has been a topic of contemporary interest. Michaelis-Arbuzov reaction is the most extensively utilized method for their preparation, which works well only with aliphatic halides. Hence, relatively harsh reaction conditions using transition-metal-catalyzed P-arylation (Arbuzov/Hirao reaction) are used for the preparation of aryl-phosphorus compounds. Presented herein is a competent process for the synthesis of aryl-phosphonates, -phosphinates, and -phosphine oxides by making an efficient use of arynes for C-P bond construction. PMID:23590457

Dhokale, Ranjeet A; Mhaske, Santosh B

2013-05-01

56

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

Directory of Open Access Journals (Sweden)

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

Muttu C.T

2010-12-01

57

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 structure–activity 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

58

Synthesis and Antifungal Activity of N-(Substituted pyridinyl-1-methyl(phenyl-3-(trifluoromethyl-1H-pyrazole-4-carboxamide Derivatives  

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Full Text Available A series of N-(substituted pyridinyl-1-methyl(phenyl-3-trifluoromethyl-1H-pyrazole-4-carboxamide derivatives were synthesized. All target compounds were characterized by spectral data (1H-NMR, 13C-NMR, IR, MS and elemental analysis and were bioassayed in vitro against three kinds of phytopathogenic fungi (Gibberella zeae, Fusarium oxysporum, Cytospora mandshurica. The results showed that some of the synthesized N-(substituted pyridinyl-1-methyl-3-trifluoromethyl-1H-pyrazole-4-carboxamides exhibited moderate antifungal activities, among which compounds 6a, 6b and 6c displayed more than 50% inhibition activities against G. zeae at 100 µg/mL, which was better than that of the commercial fungicides carboxin and boscalid.

Zhibing Wu

2012-11-01

59

N-substituted homopiperazine barbiturates as gelatinase inhibitors.  

Science.gov (United States)

Matrix metalloproteinases are implicated in a wide range of pathophysiological processes and potent selective inhibitors for these enzymes continue to be eagerly sought. 5,5-Disubstituted barbiturates hold promise as inhibitor types being stable in vivo and relatively selective for the gelatinases (MMP-2 and MMP-9). In this paper we describe the synthesis of 5-piperazine and -homopiperazine substituted barbiturates. The activity of these compounds as gelatinase inhibitors was evaluated using supernatants from 12-O-tetradecanoylphorbol-13-acetate (PMA)-stimulated HT-1080 cells as well as using recombinant human MMPs. N-Acyl homopiperazine compounds were found to be potent inhibitors of the gelatinases (range in nM) and generally more potent than the corresponding piperazine analogues. The panel of N-acyl homopiperazines was enlarged in order to exploit differences between the gelatinases at the S2' site in order to design MMP-2- or MMP-9-selective inhibitors. Compounds in this group exhibited single digit nano-molar potency and some selectivity between the two enzymes. Representative potent compounds were effective inhibitors of cancer cell migration. PMID:21764590

Wang, Jun; Medina, Carlos; Radomski, Marek W; Gilmer, John F

2011-08-15

60

Synthesis and Crystal Structures of N-Substituted Pyrazolines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

 
 
 
 
61

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

62

Synthesis and biological evaluation of N-substituted noscapine analogues.  

Science.gov (United States)

Noscapine is a phthalideisoquinoline alkaloid isolated from the opium poppy Papaver somniferum. It has long been used as an antitussive agent, but has more recently been found to possess microtubule-modulating properties and anticancer activity. Herein we report the synthesis and pharmacological evaluation of a series of 6'-substituted noscapine derivatives. To underpin this structure-activity study, an efficient synthesis of N-nornoscapine and its subsequent reduction to the cyclic ether derivative of N-nornoscapine was developed. Reaction of the latter with a range of alkyl halides, acid chlorides, isocyanates, thioisocyanates, and chloroformate reagents resulted in the formation of the corresponding N-alkyl, N-acyl, N-carbamoyl, N-thiocarbamoyl, and N-carbamate derivatives, respectively. The ability of these compounds to inhibit cell proliferation was assessed in cell-cycle cytotoxicity assays using prostate cancer (PC3), breast cancer (MCF-7), and colon cancer (Caco-2) cell lines. Compounds that showed activity in the cell-cycle assay were further evaluated in cell viability assays using PC3 and MCF-7 cells. PMID:23055449

DeBono, Aaron J; Xie, Jin Han; Ventura, Sabatino; Pouton, Colin W; Capuano, Ben; Scammells, Peter J

2012-12-01

63

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-06-15

64

Synthesis and Crystal Structures of N-Substituted Pyrazolines  

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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

65

Synthesis and crystal structures of N-substituted pyrazolines.  

Science.gov (United States)

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. PMID:23429377

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

2013-01-01

66

Superacid synthesis of halogen containing N-substituted-4-aminobenzene sulfonamides: new selective tumor-associated carbonic anhydrase inhibitors.  

Science.gov (United States)

A series of new, halogen containing N-substituted 4-aminobenzenesulfonamides were synthesized by using superacid HF/SbF5 chemistry and investigated as inhibitors of several human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms, that is, the cytosolic hCA I and II and, the tumor-associated transmembrane isoforms hCA IX and XII. Despite the substitution of the sulfonamide function, the presence of fluorine atom(s) in ? position of the sulfonamide function strongly favors hCA inhibition. A similar effect of the ?-fluorinated alkyl substitution on the amino function has been also observed. Among the tested compounds, several chlorinated derivatives have been identified as selective nanomolar, tumor-associated isoforms inhibitors. These non-primary sulfonamides probably bind in the coumarin-binding site, at the entrance of the cavity, and not to the metal ion as the primary sulfonamide inhibitors. PMID:22705188

Compain, Guillaume; Martin-Mingot, Agnès; Maresca, Alfonso; Thibaudeau, Sebastien; Supuran, Claudiu T

2013-03-15

67

?-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

68

Synthesis, biological evaluation of 9-N-substituted berberine derivatives as multi-functional agents of antioxidant, inhibitors of acetylcholinesterase, butyrylcholinesterase and amyloid-? aggregation.  

Science.gov (United States)

A series of 9-N-substituted berberine derivatives were synthesized and biologically evaluated as antioxidant and inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase and amyloid-? aggregation. Most of these compounds exhibited very good antioxidant activities, inhibitive activities of AChE and amyloid-? aggregation. Among them, compound 8d, (o-methylphenethyl)amino linked at the 9-position of berberine, was found to be a good antioxidant (with 4.05 ?M of Trolox equivalents), potent inhibitor of AChE (an IC(50) value of 0.027 ?M), and high active inhibitor of amyloid-? aggregation (an IC(50) value of 2.73 ?M). PMID:22019228

Shan, Wen-Jun; Huang, Ling; Zhou, Qi; Meng, Fan-Chao; Li, Xing-Shu

2011-12-01

69

Synthesis and antimicrobial profile of N-substituted imidazolium oximes and their monoquaternary salts against multidrug resistant bacteria.  

Science.gov (United States)

Two different series of N-substituted imidazolium oximes and their monoquaternary salts were synthesized and biologically tested with respect to their ability to inhibit growth a diverse panel of antibiotic susceptible Gram-positive and antibiotic resistant Gram-negative bacteria as well fungal strains. The newly synthesized compounds were analyzed by spectral studies to confirm their structure. The preliminary results showed that all compounds tested possess promising antimicrobial potential against both susceptible Gram-positive and antibiotic resistant Gram-negative isolates, exhibiting a wide range of MIC values from 0.14 to 100.0 ?g/mL. The structure-activity relationship demonstrates that the p-methylphenyl and p-fluorophenyl groups in monoquaternary salts 6 and 7 attached directly to the imidazolium ring could be essential for observed remarkable inhibitory profiles against clinically important pathogens Pseudomonas aeruginosa (MIC=0.14 ?g/mL) and Klebsiella pneumoniae (MIC=1.56 ?g/mL). Furthermore, the broth microdilution assay was then used to investigate the antiresistance efficacy of compound 7 against fourteen extended-spectrum ?-lactamase (ESBL)-producing strains in comparison to eight clinically relevant antibiotics. Compound 7 exhibited a remarkable antiresistance profiles ranging between 0.39 and 12.50 ?g/mL against all of ESBL-producing strains, which leads to the suggestion that may be interesting candidate for development of new antimicrobials to combat multidrug resistant Gram-negative bacteria. PMID:24126094

Odžak, Renata; Sko?ibuši?, Mirjana; Maravi?, Ana

2013-12-01

70

Pyran derivatives. Part XXI. Antiproliferative and cytotoxic properties of novel N-substituted 4-aminocoumarins, their benzo-fused derivatives, and some related 2-aminochromones.  

Science.gov (United States)

The N-substituted tricyclic 2-aminochromone derivatives 1a, 2a, and 2b were obtained by treating the corresponding (methylthio) or (methylsulfinyl) derivatives 10, 11, or 12, respectively, with an excess of the proper amines. Compound 2c was synthesized through the reaction of 2-naphthol with the ethyl N,N-diphenylmalonamate/POCl(3) reagent 14. The N-substituted 4-aminocoumarin bicyclic and tricyclic derivatives 5-8 were prepared by treating the corresponding chloro derivatives with the excess suitable amines. Compounds 1, 2, 5-8 were tested in vitro for their antiproliferative activity (DNA synthesis inhibition in Ehrlich cells) and cytotoxicity (MTT test in HeLa cells). The inhibitory properties of three selected compounds (5c, 5e, 7c) on protein and RNA syntheses in Ehrlich cells were also evaluated. Among the 27 compounds tested, 10 4-aminocoumarin derivatives (5-8) and two 2-aminochromone derivatives (1a and 2a) showed an appreciable antiproliferative activity (IC(50) range: 1.74-13.8 microM), whereas only four compounds 5-8 exhibited a comparable cytotoxic activity (IC(50) range: 4.95-12.9 microM). PMID:14572859

Di Braccio, Mario; Grossi, Giancarlo; Roma, Giorgio; Marzano, Cristina; Baccichetti, Franca; Simonato, Morena; Bordin, Franco

2003-11-01

71

Synthesis and characterization of novel efficient and thermally stable 2-aryl-5-dicyanovinylthiophenes and 5-aryl-5´-dicyanovinyl-2,2´-bithiophenes as potentially promising nonlinear optical (NLO) materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two series of dicyanovinyl-substituted compounds namely 2-aryl-5-dicyanovinyl-thiophenes 4 and 5-aryl-5´-dicyanovinyl-2,2´-bithiophenes 6 were synthesized through Knoevenagel condensation of the corresponding 2-aryl-5-formyl-thiophenes 3 and 5-aryl-5´-formyl-2,2´-bithiophene 5 precursors. On the other hand, precursors 3 were prepared through the Vilsmeier-Haack-Arnold reaction (VHA) starting from inexpensive and easily available precursors such as acetophenones. This method produced the t...

Herbivo, Cyril; Comel, Alain; Kirsch, G.; Fonseca, A. Mauri?cio C.; Belsley, M.; Raposo, M. Manuela M.

2010-01-01

72

Aryl-palladium-NHC complex: efficient phosphine-free catalyst precursors for the carbonylation of aryl iodides with amines or alkynes.  

Science.gov (United States)

A series of aryl-palladium-NHC compounds was prepared according to the reported methods and their catalytic activity in the carbonylation of aryl iodides to synthesize ?-keto amides and alkynones was examined. These practical aryl-palladium-NHC complexes have shown highly efficient catalyzed carbonylation and Sonogashira carbonylation reactions, with high turnover number in synthesis of ?-keto amides (TON = 4300) and in synthesis of alkynones (TON = 980). PMID:25350346

Zhang, Chunyan; Liu, Jianhua; Xia, Chungu

2014-12-21

73

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

Science.gov (United States)

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

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

2013-11-01

74

A diversity oriented, microwave assisted synthesis of N-substituted 2-hydro-4-amino-pyrido[2,3-d]pyrimidin-7(8H)-ones.  

Science.gov (United States)

A protocol for the synthesis of N-substituted 2-hydro-4-amino-pyrido[2,3-d]pyrimidin-7(8H)-ones (11) is described. Thus, the formylation of a 2-aminopyridone 12 in 85% formic acid/Ac(2)O, proceeding via in situ cyclization to the intermediate formamide 13, affords the corresponding 2-hydro-4-oxo-pyridopyrimidine 14, which is converted to a 4-chloro-pyridopyrimidine 15 upon treatment with POCl(3). The subsequent transformation to the title compounds is carried by treatment with the corresponding amine in MeOH under microwave irradiation conditions. PMID:19037737

Mont, Núria; Teixidó, Jordi; Borrell, José I

2009-02-01

75

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

International Nuclear Information System (INIS)

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

76

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

77

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; Nádor, K

1976-01-01

78

Neat reaction microwave technology for the synthesis of N-substituted-1,4-dihydropyridines  

International Nuclear Information System (INIS)

Hantzsch synthesis of N-substituted-1,4-dihydropyridines (1,4-DHP) was carried out using an environmentally benign procedure. Neat reactants were subjected to microwave irradiation (MWI) to give the required products in excellent yield. Appreciable results were not obtained when conventional synthesis using neat reactants was carried out. The good yield and rate enhancement observed in the case of microwave irradiation is attributed to the uniform heating effect of microwaves. (author)

79

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

Directory of Open Access Journals (Sweden)

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

Zeynep Soyer

2013-01-01

80

Peripheral arylation of subporphyrazines.  

Science.gov (United States)

Peripherally hexaarylated subporphyrazines (SubPzs) have been prepared through a Pd-catalyzed, CuTC-mediated coupling of a hexaethylsulfanylated subporphyrazine with arylboronic acids. The introduced aryl substituents strongly influence the electronic properties of the subporphyrazine through effective conjugative interaction. Aryl rings endowed with ?-electron-donating groups at the para positions produce a remarkable perturbation of the electron density of the SubPz macrocycle. This is reflected through significant redshifts of the SubPz CT and Q-bands, together with increase of the molar absorptivity of the former, with respect to those exhibited by the hexaphenyl-SubPz 2?a. Moreover, the trend in the first SubPz reduction potentials correlates with the Hammett constants (?p ) corresponding to the para substituents of the aryl. The domed, extended SubPz ?-system self-assembles in the solid state to form a dimeric capsule that houses a solvent molecule. PMID:23784931

Higashino, Tomohiro; Rodríguez-Morgade, M Salomé; Osuka, Atsuhiro; Torres, Tomás

2013-07-29

 
 
 
 
81

Synthesis of novel imbricatolic acid analogues via insertion of N-substituted piperazine at C-15/C-19 positions, displaying glucose uptake stimulation in L6 skeletal muscle cells.  

Science.gov (United States)

A new class of N-substituted piperazine analogues of imbricatolic acid have been designed and synthesized by using the appropriate synthetic routes in excellent yield. All synthesised compounds were screened for their in vitro glucose uptake stimulatory activity. Among them compounds 4b, 4e, 8b, and 8e triggered L6 skeletal muscle cells for glucose uptake at 54.73%, 40.79%, 40.90%, and 39.55% stimulation, respectively. Compound 4b has emerged as important lead compound showing potential antidiabetic activity. Illustration about their synthesis and in vitro glucose uptake activity is described. PMID:22726926

Khan, Mohammad Faheem; Kumar, Padam; Pandey, Jyotsana; Srivastava, Arvind Kumar; Tamrakar, Akhilesh Kumar; Maurya, Rakesh

2012-07-15

82

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

83

Synthesis and complexing properties of N-substituted mono- or diaza-crown ethers  

International Nuclear Information System (INIS)

N-substituted mono- or diaza-crown ethers, containing fragments of ethylacetate, ethylene glycol ethers, n-methoxy and n-nitrobenzene group in their lateral chains, were synthesized. Their interaction with ions of alkali and alkaline-earth metals (MI=Li-Cs; MII=Ca, Sr, Ba) was studied by the method of pH-metric titration in methanol at 25 Deg C.; It is shown that introduction of substituent changes the complexing ability of basic macrocycle as a result of nitrogen atoms basicity change and participation of the lateral groups in additional coordination with the complexing ion

84

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

International Nuclear Information System (INIS)

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

85

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; Madsen, Robert

2008-01-01

86

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

87

Synthesis and characterization of partially fluorinated poly(aryl) ionomers for polymer electrolyte membrane fuel cells and ESR-spectroscopic investigation of the radically induced degradation of model compounds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Im ersten Teil dieser Arbeit werden zunächst verschiedene Strategien zum Aufbau sulfonierter teilfluorierter Poly(aryl)e entwickelt und synthetisch umgesetzt. Konzeptionell liegt dabei die Hypothese zugrunde, dass sich teilfluorierte Poly(aryl)-Ionomere gegenüber nichtfluorierten durch eine erhöhte Acidität auszeichnen. Außerdem weisen sie eine höhere Bindungsdissoziationsenergie sowohl der C-F-Bindungen als auch der benachbarten C-H-Bindungen auf, womit ein Gewinn an radikalischer und ...

Scho?nberger, Frank

2008-01-01

88

Synthesis and Photophysical Properties of 2-Aryl-6,8-bis(arylethenyl-4-methoxyquinolines  

Directory of Open Access Journals (Sweden)

Full Text Available Iodine-methanol mediated oxidative-aromatization of 2-aryl-6,8-dibromo-2,3-dihydroquinolin-4(1H-ones afforded the corresponding 2-aryl-6,8-dibromo-4-methoxy-quinolines in high yield and purity. The isomeric 1-(2-amino-3,5-dibromophenyl-3-aryl-2-propen-1-ones reacted with iodine in methanol afford in a single pot operation the corresponding 2-aryl-6,8-dibromo-4-methoxyquinoline (major and 2-aryl-6,8-dibromoquinolin-4(1H-one (minor products that were separated in sequence by column chromatography on silica gel. Suzuki-Miyaura cross-coupling of the 6,8-dibromo-4-methoxyquinoline derivatives with excess arylvinylboronic acids afforded the corresponding 2-aryl-6,8-bis(2-arylethenyl-4-methoxyquinolines. The absorption and fluorescence properties of these compounds were also determined.

Tebogo Ankie Khoza

2012-11-01

89

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

Scientific Electronic Library Online (English)

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

G.E., Camí; M.del C., Ramírez de Arellano; S., Fustero; J.C., Pedregosa.

90

Metal-free, one-pot conversion of proline derivatives into 2-aryl-3-iodo pyrrolidines by a sequential scission-iodination-arylation process.  

Science.gov (United States)

The metal-free, direct conversion of readily available proline derivatives into 2-aryl-3-iodopyrrolidines is carried out under mild conditions and in good yields, using a sequential radical decarboxylation-oxidation-iodination-arylation reaction. These iodinated pyrrolidines are valuable precursors of other compounds. For instance, they can be cyclized to tricyclic compounds or undergo dehalogenation to 2-aryl-2,5-dihydro-1H-pyrroles, which are iminosugar and 2-arylpyrrole precursors. This process provides a short pathway to a variety of alkaloid and drug analogues of potential pharmaceutical interest. PMID:25333212

Batchu, Venkateswara Rao; Romero-Estudillo, Iván; Boto, Alicia; Miguélez, Javier

2014-12-21

91

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

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Full Text Available Quaternary ammonium ionomers of Methacrylamidopropyltrimethyl ammonium chloride with N-substituted acrylamides were prepared at 55±1°C 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

92

Effect of Secondary Structure on the Persistence Length of a Poly N-substituted Glycine  

Science.gov (United States)

A polymer containing helical secondary structure is shown to be nearly as flexible as a chemically analogous polymer containing no structure. Polypeptoids or poly N-substituted glycines are a class of sequence specific polymers in which chain shape can be controlled via monomer choice involving both sterics and chirality. In this study, a polypeptoid containing aromatic chiral sidechains was synthesized. Classical measurements such as circular dichroism and NMR have shown previously that the bulky chiral side chains cause the polypeptoid to adopt a helical conformation. However, small angle neutron scattering demonstrated that in acetonitrile, the persistence length of the helical polypeptoid was approximately 1 nm, only about 15% of the fully extended helical length. This small persistence length indicates that the chain likely adopts several conformations in solution and is not rigidly locked into its helical shape throughout the entire length of the polymer

Murnen, Hannah K.; Rosales, Adrianne M.; Kline, Steven R.; Zuckermann, Ronald N.; Segalman, Rachel A.

2012-02-01

93

N-Substituted acetamidines and 2-methylimidazole derivatives as selective inhibitors of neuronal nitric oxide synthase.  

Science.gov (United States)

A series of N-substituted acetamidines and 2-methylimidazole derivatives structurally related to W1400 were synthesized and evaluated as Nitric Oxide Synthase (NOS) inhibitors. Analogs with sterically hindering isopropyl and phenyl substituents on the benzylic carbon connecting the aromatic core of W1400 to the acetamidine nitrogen, showed good inhibitory potency for nNOS (IC(50)=0.2 and 0.3 ?M) and selectivity over eNOS (500 and 1166) and to a lesser extent over iNOS (50 and 100). A molecular modeling study allowed to shed light on the effects of the structural modifications on the selectivity of the designed inhibitors toward the different NOS isoforms. PMID:20933416

Maccallini, Cristina; Patruno, Antonia; Lannutti, Fabio; Ammazzalorso, Alessandra; De Filippis, Barbara; Fantacuzzi, Marialuigia; Franceschelli, Sara; Giampietro, Letizia; Masella, Simona; Felaco, Mario; Re, Nazzareno; Amoroso, Rosa

2010-11-15

94

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

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

Rodney J. Ouellette

2010-08-01

95

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

International Nuclear Information System (INIS)

Highlights: ? N-substituted 5,5-diphenylhydantoins and 1,3-thiazolidine-2,4-diones were prepared. ? All synthesized compounds showed good inhibition effect in oil–water medium. ? The test results were supported with water contact angle measurements and with SEM. ? 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, 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.

96

Direct N9-arylation of purines with aryl halides  

DEFF Research Database (Denmark)

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

Larsen, Anders Foller; Ulven, Trond

2014-01-01

97

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

Science.gov (United States)

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

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

2011-08-15

98

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

99

Hammett dependences and deuterium kinetic isotope effect in arylation and dimerization reactions of substituted styrenes under palladium (2) action  

International Nuclear Information System (INIS)

Kinetics of oxidative dimerization of n-substituted styrenes under the effect of acetate Pd(2) has been studied. Kinetic isotope effect of the reaction k(C6H5CH = CH2)/kx(C6H5CH = CD2) = 3.0+-0.1 is found. The reaction rate constants obey the Hammett equation with inclination rho=-2.4. Using the method of competing reactions relative rate constants of phenyl group transfer for n-substituted styrenes in the reaction of their oxidative arylation with benzene under the effect of Pd(2) acetate are determined. The absence of isotope effect and simple Hammett correlation for the constants is established, however, they are in a satisfactory agreement with modified equation of the type lg(ksub(X)/ksup(H)) = 1.65 ? - 0.95 ?+

100

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

Science.gov (United States)

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

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

2010-03-10

 
 
 
 
101

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

102

ON THE ANTIOXIDANT EFFECTIVENESS OF N,N´–SUBSTITUTED 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 C–H 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.

Vladimír Lukeš

2004-10-01

103

CO2 adsorption thermodynamics over N-substituted/grafted graphanes: a DFT study.  

Science.gov (United States)

This work examines CO2 adsorption over various N-substituted/grafted graphanes to identify the promotional effects of various N-functionalities have on the adsorption characteristics using DFT. CO2 adsorbs weakly on a graphane surface functionalized with a single, isolated substituted N- or grafted NH2-sites. The presence of coadsorbed H2O on the surface promotes CO2 adsorption on both N- and NH2-sites, with highly exothermic adsorption energies (?-50 kJ mol(-1)). Directly grafted -NH2 or -OH functional groups on C atoms adjacent to C atoms which have a -NH2 group grafted suffer from geometrical restrictions preventing dual stabilization of formed carbamate upon adsorption of CO2. CO2 adsorption can be greatly enhanced with the presence of a -OH group or second -NH2 group in the proximity of a -NH2 site on graphane, and only if a n(-CH2-) (n ? 1) linker is introduced between the -NH2 or -OH and graphane surface (adsorption energies of -58.8 or -43.1 kJ mol(-1) at n = 2). The adsorption mechanistics provided by DFT can be used to guide the atomic-level rational design of N-based graphane and carbon adsorbents for CO2 capture. PMID:24475953

Xiao, Jing; Sitamraju, Siddarth; Janik, Michael J

2014-02-25

104

Functionality of aryl hydrocarbon receptors (AhR1 and AhR2) of white sturgeon (Acipenser transmontanus) and implications for the risk assessment of dioxin-like compounds.  

Science.gov (United States)

Worldwide, populations of sturgeons are endangered, and it is hypothesized that anthropogenic chemicals, including dioxin-like compounds (DLCs), might be contributing to the observed declines in populations. DLCs elicit their toxic action through activation of the aryl hydrocarbon receptor (AhR), which is believed to regulate most, if not all, adverse effects associated with exposure to these chemicals. Currently, risk assessment of DLCs in fishes uses toxic equivalency factors (TEFs) developed for the World Health Organization (WHO) that are based on studies of embryo-lethality with salmonids. However, there is a lack of knowledge of the sensitivity of sturgeons to DLCs, and it is uncertain whether TEFs developed by the WHO are protective of these fishes. Sturgeons are evolutionarily distinct from salmonids, and the AhRs of sturgeons differ from those of salmonids. Therefore, this study investigated the sensitivity of white sturgeon (Acipenser transmontanus) to DLCs in vitro via the use of luciferase reporter gene assays using COS-7 cells transfected with AhR1 or AhR2 of white sturgeon. Specifically, activation and relative potencies (RePs) of 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachloro-dibenzofuran, 2,3,7,8-tetrachloro-dibenzofuran, 3,3',4,4',5-pentachlorobiphenyl, 3,3',4,4'-tetrachlorobiphenyl, and 2,3,3',4,4'-pentachlorobiphenyl were determined for each AhR. It was demonstrated that white sturgeon expresses AhR1s and AhR2s that are both activated by DLCs with EC50 values for 2,3,7,8-TCDD that are lower than those of any other AhR of vertebrates tested to date. Both AhRs of white sturgeon had RePs for polychlorinated dibenzofurans more similar to TEFs for birds, while RePs for polychlorinated biphenyls were most similar to TEFs for fishes. Measured concentrations of select DLCs in tissues of white sturgeon from British Columbia, Canada, were used to calculate toxic equivalents (TEQs) by use of TEFs for fishes used by the WHO and TCDD equivalents (TCDD-EQs) via the use of RePs for AhR2 of white sturgeon as determined by transfected COS-7 cells. TCDD-EQs calculated for endangered populations of white sturgeon were approximately 10-fold greater than TEQs and were within ranges known to cause adverse effects in other fishes, including other species of sturgeons. Therefore, TEFs used by the WHO might not adequately protect white sturgeon, illuminating the need for additional investigation into the sensitivity of these fish to DLCs. PMID:24950391

Doering, Jon A; Farmahin, Reza; Wiseman, Steve; Kennedy, Sean W; Giesy, John P; Hecker, Markus

2014-07-15

105

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

106

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

107

New 1-Aryl-3-Substituted Propanol Derivatives as Antimalarial Agents  

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Full Text Available This paper describes the synthesis and in vitro antimalarial activity against a P. falciparum 3D7 strain of some new 1-aryl-3-substituted propanol derivatives. Twelve of the tested compounds showed an IC50 lower than 1 ?M. These compounds were also tested for cytotoxicity in murine J774 macrophages. The most active compounds were evaluated for in vivo activity against P. berghei in a 4-day suppressive test. Compound 12 inhibited more than 50% of parasite growth at a dose of 50 mg/kg/day. In addition, an FBIT test was performed to measure the ability to inhibit ferriprotoporphyrin biocrystallization. This data indicates that 1-aryl-3-substituted propanol derivatives hold promise as a new therapeutic option for the treatment of malaria.

Antonio Monge

2009-10-01

108

Nucleophilic addition of nitrogen to aryl cations: mimicking Titan chemistry.  

Science.gov (United States)

The reactivity of aryl cations toward molecular nitrogen is studied systematically in an ion trap mass spectrometer at 10(2) Pascal of nitrogen, the pressure of the Titan main haze layer. Nucleophilic addition of dinitrogen occurs and the nature of aryl group has a significant influence on the reactivity, through inductive effects and by changing the ground state spin multiplicity. The products of nitrogen activation, aryldiazonium ions, react with typical nitriles, aromatic amines, and alkynes (compounds that are relevant as possible Titan atmosphere constituents) to form covalently bonded heterocyclic products. Theoretical calculations at the level [DFT(B3LYP)/6-311++G(d,p)] indicate that the N2 addition reaction is exothermic for the singlet aryl cations but endothermic for their triplet spin isomers. The -OH and -NH2 substituted aryl ions are calculated to have triplet ground states, which is consistent with their decreased nitrogen addition reactivity. The energy needed for the generation of the aryl cations from their protonated precursors (ca. 340 kJ/mol starting with protonated aniline) is far less than that required to directly activate the nitrogen triple bond (the lowest energy excited state of N2 lies ca. 600 kJ/mol above the ground state). The formation of aza-aromatics via arene ionization and subsequent reactions provide a conceivable route to the genesis of nitrogen-containing organic molecules in the interstellar medium and Titan haze layers. PMID:23982933

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

2013-11-01

109

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

110

Chemometric approach in studying of the retention behavior and lipophilicity of potentially biologically active N-substituted-2-phenylacetamide derivatives  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A atividade biológica potencial de moléculas depende largamente da sua lipofilicidade. A lipofilicidade de derivados de 2-fenilacetamida N-substituída foi investigada experimentalmente, aplicando cromatografia em camada delgada em fase inversa (RP-TLC em RP 18 F254s) na presença de etanol e de dioxa [...] no, e usando pacotes de software. A fim de estabelecer a dependência entre a lipofilicidade obtida de diferentes formas foram usados análise de regressão linear e métodos multivariados. Agrupamentos aproximadamente semelhantes dos parâmetros lipofílicos e dos compostos testados foram registados no caso de ambos os métodos quimiométricos usados. Todos os resultados obtidos confirmam o fato de que as análises de regressão linear e multivariada aplicadas oferecem oportunidades para comparar os dados sobre a retenção cromatográfica e parâmetros lipofílicos dos derivados de fenilacetamida investigados. Os resultados sugerem que a lipofilicidade das moléculas estudadas depende largamente da natureza dos substituintes ligados ao átomo de nitrogênio e, por outro lado, que as constantes retenção cromatográfica, R M0, determinada pelo método de RP-TLC, são semelhantes à medida padrão de lipofilicidade, log P, o que torna este método adequado para a previsão de lipofilicidade. Abstract in english The potential biological activity of a molecule largely depends on its lipophilicity. The lipophilicity of derivatives of N-substituted-2-phenylacetamide was investigated experimentally, by applying thin-layer chromatography on reversed phase (RP-TLC on RP 18 F254s) in the presence of ethanol and di [...] oxane and by using relevant software packages. In order to establish dependence between lipophilicity obtained in different ways, linear regression analysis and multivariate methods were used. Approximately similar groupings of lipophilic parameters and tested compounds were registered in case of both chemometric methods. The obtained results confirm the fact that the applied linear regression analysis and multivariate analysis provide opportunities for comparing chromatographic retention data and lipophilic parameters of the investigated phenylacetamide derivatives. Results suggest that the lipophilicity of investigated molecules largely depends on the nature of the substituents linked to nitrogen atom and on the other hand that the chromatographic retention constants, R M0, determined by RP-TLC method, are similar to the standard measure of lipophilicity, log P, which makes this method appropriate for predicting lipophilicity.

Gyöngyi Gy., Vastag; Suzana Lj., Apostolov; Borko M., Matijevi& #263; ; Aleksandar D., Marinkovi& #263; .

1948-19-01

111

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

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

Milan Potácek

1999-08-01

112

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

113

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

International Nuclear Information System (INIS)

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 Cs2CO3 or K2CO3 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

114

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

115

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

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

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

2011-01-01

116

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

117

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

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Full Text Available A new series of asymmetrically N,N'-substituted ureas 20–25 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 20–25 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

NiXantphos: a deprotonatable ligand for room-temperature palladium-catalyzed cross-couplings of aryl chlorides.  

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

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

2014-04-30

119

Palladium-catalyzed aminosulfonylation of aryl halides.  

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

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

2010-01-01

120

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 6a–f. 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) 9a–d and the N-(2-aminoethyl) 10a–d 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, 12a–d, 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

 
 
 
 
121

Radiation protection agents : synthesis of some N-substituted mercapto alkyl guanidines, isothiouronium salts and thiosulphuric acid derivatives I  

International Nuclear Information System (INIS)

The aromatic guanidines prepared from substituted anilines with the help of S-methyl isothiourea sulphate when treated with excess of ?-?-dibromo alkanes in presence of pyridine yielded N-aryl-N'-(?-bromo) alkyl guanidines (1). 1 were used to synthesise radiation protection agents : (i) N-aryl-N'-(?-mercapto) alkyl guanidines was obtained by treating 1 with sodium hydrogen sulphade, (ii) isothiouronium salts (Bunte salts) by treating 1 with thiourea and (iii) thiosulphuric acid derivatives by treating hydrobromide salts of 1 with sodium thiosulphate. (M.G.B.)

122

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

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

Michelle Farbaniec

2013-04-01

123

Gold-catalyzed direct arylation.  

Science.gov (United States)

Biaryls (two directly connected aromatic rings, Ar(1)-Ar(2)) are common motifs in pharmaceuticals, agrochemicals, and organic materials. Current methods for establishing the Ar(1)-Ar(2) bond are dominated by the cross-coupling of aryl halides (Ar(1)-X) with aryl metallics (Ar(2)-M). We report that, in the presence of 1 to 2 mole percent of a gold catalyst and a mild oxidant, a wide range of arenes (Ar(1)-H) undergo site-selective arylation by arylsilanes (Ar(2)-SiMe(3)) to generate biaryls (Ar(1)-Ar(2)), with little or no homocoupling (Ar(1)-Ar(1)/Ar(2)-Ar(2)). Catalysis proceeds at room temperature and tolerates a broad range of functional groups, including those incompatible with cross-coupling. These features expedite biaryl preparation, as demonstrated by synthesis of the nonsteroidal anti-inflammatory diflunisal. PMID:23019647

Ball, Liam T; Lloyd-Jones, Guy C; Russell, Christopher A

2012-09-28

124

Synthesis and opioid activity of enantiomeric N-substituted 2,3,4,4a,5,6,7,7a-octahydro-1H-benzofuro[3,2-e]isoquinolines.  

Science.gov (United States)

A series of enantiomeric N-substituted 2,3,4,4a,5,6,7,7a-octahydro-1H-benzofuro[3,2-e]isoquinolines was synthesized. The (-)-enantiomers had much greater kappa-, mu-, and delta-opioid receptor binding affinity than the corresponding (+)-enantiomers. Compounds (-)-1a, (-)-1b, and (-)-1c displayed subnanomolar binding affinity for the mu-receptor, and (-)-1b had a high affinity for the kappa-receptor. Compound (-)-1a was a mu-partial agonist and kappa-antagonist. Compound (-)-1b was a potent neutral mu-antagonist (K(d) = 0.22 nM) and a kappa-partial agonist. PMID:20055417

Hsin, Ling-Wei; Chang, Li-Te; Rothman, Richard B; Dersch, Christina M; Fishback, James A; Matsumoto, Rae R

2010-02-11

125

Enzyme Inhibition Studies on N-Substituted Sulfonamides Derived from m-phenetidine  

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Organic synthesis of various compounds followed by biological activities is the going on methodology in the world for pharmacological evaluation. The undertaken research is the synthesis of N-(3-ethoxyphenyl)-4-methylbenzenesulfonamide (3) through condensation reaction of m-phenetidine (1) and -methylbenzenesulfonyl chloride (2) using basic aqueous media of sodium carbonate. Further, the synthesized compound 3 was reacted with different alkyl/aralkyl halides (4a-j) using DMF as aprotic polar ...

Ashraf, M.; Gul, S.; Siddiqui, S. Z.; Rasool, S.; Abbasi, M. A.; Siddiqa, A.; Aziz-ur-Rehman; Nasar, R.

2013-01-01

126

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

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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

127

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)

128

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

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Full Text Available A series of novel substituted 1-amino-3-(5-phenyl-4, 5-dihydro-1H-pyrazol-3-yl quinolin-2(1H-one (AJP1-AJP8 have been synthesized upon reaction with 1-amino-3-cinnamoyl-quinolin-2(1H-one by using hydrazine hydrate as cyclising medium in alcohol medium. 1-amino-3-cinnamoyl-quinolin-2(1H-one were synthesized by condensing 3-acetyl-1-amino-quinolin-2-one with different substituted benzaldehyde in presence of ethanolic KOH. The structures of the final synthesized compounds were confirmed by IR, 1H NMR and mass spectra. The synthesized compounds were screened for their antibacterial and antifungal activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans, Aspergillus niger respectively by cup plate method. Compounds AJP1, AJP3, AJP4, AJP5, AJP6 and AJP7 showed good antibacterial activity compared to the standard drug amoxicillin. Compounds AJP1, AJP3, AJP5 and AJP7 showed moderate antifungal activity compared to the standard drug fluconazole. The synthesized compounds were screened for their anti-inflammatory activity by Carrageenan induced paw edema method. Compounds AJP1 and AJP7 showed significant anti-inflammatory activity compared to the standard drug diclofenac sodium.

Jennifer Fernandes

2013-10-01

129

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

Science.gov (United States)

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

Lapadatescu, Carmen; Ginies, Christian; Le Quere, Jean-Luc; Bonnarme, Pascal

2000-01-01

130

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

Science.gov (United States)

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

Lapadatescu, C; Giniès, C; Le Quéré, J L; Bonnarme, P

2000-04-01

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

2-Substituted N-aryl piperazines as novel triple reuptake inhibitors for the treatment of depression.  

Science.gov (United States)

Recently a class of compounds known as triple reuptake inhibitors has emerged as a new strategy for the treatment of depression. These compounds work by simultaneously inhibiting the synaptic reuptake of serotonin, norepinephrine and dopamine. In this Letter we describe the optimization of a novel series of 2-substituted N-aryl piperazine based triple reuptake inhibitors. PMID:20570146

Carter, David S; Cai, Hai-Ying; Lee, Eun Kyung; Iyer, Pravin S; Lucas, Matthew C; Roetz, Ralf; Schoenfeld, Ryan C; Weikert, Robert J

2010-07-01

133

Antibacterial, antifungal and cytotoxic properties of novel N-substituted sulfonamides from 4-hydroxycoumarin.  

Science.gov (United States)

A new series of 4-({[2, 4-dioxo-2H-chromen-3 (4H)-ylidene] methyl} amino) sulfonamides have been obtained by the condensation reaction of 4-hydroxycoumarin with various sulfonamides (sulfanilamide, sulfaguanidine, p-aminomethyl-sufanilamide, p-aminoethylsufanilamide, sulfathiazole, sulfamethoxazole, sulfamethazine and 4-[(2-amino-4-pyrimidinyl) amino] benzenesulfonamide) in the presence of an excess of ethylorthoformate. These compounds were screened for their in-vitro antibacterial activity against four Gram-negative (E. coli, S. flexneri, P. aeruginosa and S. typhi) and two Gram-positive (B. subtilis and S. aureus) bacterial strains and for in-vitro antifungal activity against T. longifusus, C. albicans, A. flavus, M. canis, F. solani and C. glaberata. Results revealed that a significant antibacterial activity was observed by compounds (4) and (5), (6) and (8) against two Gram-negative, (P. aeruginosa and S. typhi) and two Gram-positive (B. subtilis and S. aureus) species, respectively. Of these (4) was found to be the most active. Similarly, for antifungal activity compounds (3) and (8) showed significant activity against M. canis and, (6) and (8) against F. solani. The brine shrimp bioassay was also carried out to study their in-vitro cytotoxic properties and only two compounds, (4) and (8) possessing LD50 = 2.9072 x 10(-4) and 3.2844 x 10(-4) M, respectively, displayed potent cytotoxic activity against Artemia salina PMID:17252948

Chohan, Zahid H; Shaikh, Ali U; Rauf, Abdul; Supuran, Claudiu T

2006-12-01

134

N-substituted pyrrolidines and tetrahydrofurans as novel AMPAR positive modulators.  

Science.gov (United States)

A series of novel AMPA receptor positive modulators displaying CNS penetration have been discovered with sub-micromolar activity and good selectivity over the cardiac channel receptor, hERG. We describe here the synthesis of these compounds which are biaryl pyrrolidine and tetrahydrofuran sulfonamides and disclose their activities against the human GluA2 flip isoform homotetrameric receptor. PMID:20971003

Thewlis, Kevin M; Aldegheri, Laura; Harries, Mark H; Mookherjee, Claudette; Oliosi, Beatrice; Ward, Simon E

2010-12-01

135

Room-Temperature Chromium(II)-Catalyzed Direct Arylation of Pyridines, Aryl Oxazolines, and Imines Using Arylmagnesium Reagents.  

Science.gov (United States)

We report a CrCl2-catalyzed oxidative arylation of various pyridines, aryl oxazolines, and aryl imines using aromatic Grignard reagents in the presence of 2,3-dichlorobutane (DCB). Most of the reactions proceed rapidly at 25 °C and do not require any additional ligand. Benzo[h]quinoline, 2-arylpyridine, aryl oxazoline, and imines were successfully arylated in good yields under these conditions. A TMS-substituent was used to prevent double arylation. After oxidative cross-coupling the TMS-group was further converted to a second ortho-aryl substituent. Remarkably, inexpensive aryl N-butylimine derivatives are excellent substrates for this oxidative arylation. PMID:25230000

Kuzmina, Olesya M; Knochel, Paul

2014-10-01

136

Ruthenium(II)-catalyzed sp3 C-H bond arylation of benzylic amines using aryl halides.  

Science.gov (United States)

A ruthenium(II)-catalyzed protocol for the direct arylation of benzylic amines was developed. Employing 3-substituted pyridines as directing groups, arylation was achieved using aryl bromides or aryl iodides as the aryl source. Potassium pivalate proved to be an important additive in this transformation. The arylation took place selectively in the benzylic sp(3) position, and no significant competitive sp(2) arylation was observed. Arylated imines were observed as byproducts in minor amounts. Additionally, reaction conditions for cleaving the pyridine group were established, enabling access to bis-arylated methylamines. PMID:22789033

Dastbaravardeh, Navid; Schnürch, Michael; Mihovilovic, Marko D

2012-07-20

137

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 conversão direta de nitrilas a amidas N-substituídas. A síntese seletiva do tipo one pot de amidas N-substituídas a partir de nitrilas e aminas primárias foi realiza [...] da em refluxo de água. O catalisador foi recuperado e reusado no mínimo 4 vezes, mantendo a sua eficiência. 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

138

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

Science.gov (United States)

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

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

2012-09-15

139

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

140

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

Directory of Open Access Journals (Sweden)

Full Text Available 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%.

Moara T. da Silva

2012-06-01

 
 
 
 
141

N-SUBSTITUTION AND á1-ADRENERGIC RECEPTOR AFFINITY OF LAUDANOSINE ANALOGUES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 [³H]pr...

PATRICIO ITURRIAGA-VÁSQUEZ; Cassels, Bruce K.; Dolores Ivorra, M.; Ocon, M. Pilar D.

2006-01-01

142

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Mu?ller, Thomas J. J.; Eugen Merkul; Gers, Charlotte F.; Christina Boersch; Lucilla Levi

2011-01-01

143

Compound  

Science.gov (United States)

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

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

2014-06-01

144

Rh(I)-Catalyzed Direct Arylation of Pyridines and Quinolines  

Energy Technology Data Exchange (ETDEWEB)

The pyridine and quinoline nuclei are privileged scaffolds that occupy a central role in many medicinally relevant compounds. Consequently, methods for their expeditious functionalization are of immediate interest. However, despite the immense importance of transition-metal catalyzed cross-coupling for the functionalization of aromatic scaffolds, general solutions for coupling 2-pyridyl organometallics with aryl halides have only recently been presented. Direct arylation at the ortho position of pyridine would constitute an even more efficient approach because it eliminates the need for the stoichiometric preparation and isolation of 2-pyridyl organometallics. Progress towards this goal has been achieved by activation of the pyridine nucleus for arylation via conversion to the corresponding pyridine N-oxide or N-iminopyridinium ylide. However, this approach necessitates two additional steps: activation of the pyridine or quinoline starting material, and then unmasking the arylated product. The use of pyridines directly would clearly represent the ideal situation both in terms of cost and simplicity. We now wish to document our efforts in this vein, culminating in an operationally simple Rh(I)-catalyzed direct arylation of pyridines and quinolines. We recently developed an electron-rich Rh(I) system for catalytic alkylation at the ortho position of pyridines and quinolines with alkenes. Therefore, we initially focused our attention on the use of similarly electron-rich Rh(I) catalysts for the proposed direct arylation. After screening an array of electron-rich phosphine ligands and Rh(I) salts, only marginal yields (<20%) of the desired product were obtained. Much more efficient was an electron-poor Rh(I) system with [RhCl(CO){sub 2}]{sub 2} as precatalyst (Table 1). For the direct arylation of picoline with 3,5-dimethyl-bromobenzene, addition of P(OiPr){sub 3} afforded a promising 40% yield of the cross coupled product 1a (entry 1). The exclusion of phosphite additive proved even more effective, with the yield of 1a improving to 61% (entry 2). Further enhancement in yield was not observed upon the inclusion of other additives such as MgO (entry 3), various organic bases (entries 4, 5), or a protic acid source (entry 6). Absolute concentration proved very important, with the best results being obtained at relatively high concentrations of the aryl bromide (compare entries 7 and 8). A marginal improvement was observed upon running the reaction with 6 equivalents of 2-methyl pyridine (entry 9). The reaction temperature could also be increased to 175 or 190 C while maintaining reaction yield, to enable the reaction time to be reduced to 24 h (entries 10 and 11). In summary, we have developed a Rh(I)-catalyzed strategy for the direct arylation of pyridines and quinolines. The heterocycle is used without the need for prefunctionalization, and all reaction components are inexpensive and readily available. The strategy represents an expeditious route to an important class of bis(hetero)aryls and should be of broad utility.

Berman, Ashley; Lewis, Jared; Bergman, Robert; Ellman, Jonathan

2008-07-29

145

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

146

Aryl hetaryl ketones and thioketones as efficient inhibitors of peptidyl-prolyl cis-trans isomerases.  

Science.gov (United States)

A series of 18 differently substituted new aryl hetaryl ketones and thioketones were synthesized in four to six steps from commercial starting materials. The new ketones were evaluated as inhibitors of the peptidyl-prolyl cis-trans isomerase hPin1 with K(i) values ranging in the one-digit micromolar to sub-micromolar numbers. A crystal structure revealed the non-planar arrangement of the aryl residues at the carbonyl compound and supports the hypothesis that the new compounds might mimic the transition state of the enzymatic conversion. PMID:23161639

Hediger, Thomas; Frank, Walter; Schumann, Michael; Fischer, Gunter; Braun, Manfred

2012-11-01

147

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

Science.gov (United States)

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

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

2009-12-15

148

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

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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

149

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

150

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, Réjean; Berthe, Franck C J; Siah, Ahmed

2011-11-01

151

Ring[bond]chain tautomerism of 2-Aryl-substituted cis- and trans-decahydroquinazolines.  

Science.gov (United States)

In CDCl(3) at 300 K, 2-aryl-substituted cis- and trans-3-isopropyldecahydroquinazolines and trans-3-phenyldecahydroquinazolines proved to be three-component (r(1)[bond]o[bond]r(2)) ring[bond]chain tautomeric mixtures, whereas only ring-closed tautomers could be detected for the 3-methyl-substituted analogues. The proportions of the ring-chain tautomeric forms at equilibrium were strongly influenced by the N-substitutents and the cis-trans ring junction and could be described by the equation log K(X) = rho sigma(+) + log K(X=H). These are the first examples among 2-aryl-1,3-N,N-heterocycles of a three-component ring-chain tautomeric equilibrium characterized by a Hammett-type equation. The stabilities of the ring-closed forms of cis- and trans-2-aryldecahydroquinazolines and the corresponding 3,1-benzoxazines were found to increase in the following sequence of the heteroatom at position 3: NPh < N-i-Pr < O < NMe. PMID:12098282

Lázár, László; Göblyös, Anikó; Martinek, Tamás A; Fülöp, Ferenc

2002-07-12

152

N-SUBSTITUTION AND á1-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 [³H]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-VÁSQUEZ; BRUCE K, CASSELS; M. DOLORES, IVORRA; M. PILAR, D' OCON.

2006-09-01

153

N-SUBSTITUTION AND á1-ADRENERGIC RECEPTOR AFFINITY OF LAUDANOSINE ANALOGUES  

Directory of Open Access Journals (Sweden)

Full Text Available Benzyltetrahydroisoquinoline (BTHIQ molecules are able to adopt widely differing conformations that depend on the presence or absence of N-substituents. To assess the possible role of BTHIQ conformation on the affinity of these compounds for a 1-adrenergic receptors, of interest for the management of hypertension, the racemic N-unsubstituted BTHIQ norlaudanosine and a series of N-alkylated derivatives were assessed for binding to rat brain cortical sites labelled with the radioligand [³H]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-VÁSQUEZ

2006-09-01

154

Discovery of simplified N²-substituted pyrazolo[3,4-d]pyrimidine derivatives as novel adenosine receptor antagonists: efficient synthetic approaches, biological evaluations and molecular docking studies.  

Science.gov (United States)

In the present study, a molecular simplification approach was employed to design novel bicyclic pyrazolo[3,4-d]pyrimidine (PP) derivatives from tricyclic pyrazolo[4,3-e]-1,2,4-triazolo-[1,5-c]pyrimidines (PTP) as promising human A3 adenosine receptor (hA3AR) antagonists. All the target compounds were synthesized using novel and efficient synthetic schemes and the structure-activity relationship studies of these PPs were explored through the synthesis of a series of PTP analogues with various substituents. Substituents with different lipophilicity and steric hindrance (e.g., alkyl and aryl-alkyl) functions were introduced at N(2) position of the pyrazole ring, while acyl groups with different electronic properties were introduced at C(6) position of the bicyclic nucleus to probe both electronic and positional effects. Most of the synthesized derivatives of the PP series presented good affinity at the hA3AR, as indicated by the low micromolar range of Ki values and among them, compound 63 with N(2) neopentyl substituents showed most potent hA3AR affinity with Ki value of 0.9 ?M and high selectivity (hA1AR/hA3AR=>111 & hA2AAR/hA3AR=>111) towards other adenosine receptor subtypes. Interestingly, small isopropyl groups at N(2) position displayed high affinity at another receptor subtype (hA2AAR, e.g., compound 55, with Ki hA2AAR=0.8 ?M), while they were less favorable at the hA3AR. Molecular docking analysis was also performed to predict the possible binding mode of target compounds inside the hA3AR and hA2AAR. Overall, PP derivatives represent promising starting points for new AR antagonists. PMID:24518296

Venkatesan, Gopalakrishnan; Paira, Priyankar; Cheong, Siew Lee; Vamsikrishna, Kosaraju; Federico, Stephanie; Klotz, Karl-Norbert; Spalluto, Giampiero; Pastorin, Giorgia

2014-03-01

155

Synthesis and antitubercular evaluation of aryl substituted 2-oxazolines from L-amino acids  

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes the synthesis and the in vitro antibacterial activity of a series of twelve substituted aryl-2-oxazolines against Mycobacterium tuberculosis. Seven compounds showed activity and two compounds exhibited a minimal inhibitory concentration (MIC of 25 ?g/mL were not cytotoxic for the host cells in cell viability assay. These results could be a good starting point for the development of new antitubercular lead series based on this family of compounds.

Leidiane Araújo de Souza

2014-07-01

156

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, Møller-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

157

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

158

Gas chromatograpic retention indices for N-substituted amino s-triazines on capillary columns. Part IV. Influence of column polarity on retention index  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The retention index increment for the addition of a methylene group to the alkyl group of an analyte molecule is shown to be lower than 100 i.u. for N-substituted amino s-triazines. In temperature progammed gas chromatography, a linearly interpolated retention index I, determined from the linear regression equation, I = AZ + (GRF)z, with the number of atoms (Z) in the molecule as variable, was used to describe the retention of 25 N-substituted amino s-triazines, on DB-1, DB-5 and DB-WAX capil...

Rajkovic, Olga S.; Jovanovic, Bratislav Z.; GORDANA BONCIC-CARICIC; Antonovic, Dusan G.; Mijin, Dusan Z.

2003-01-01

159

Design and synthesis of N-aryl isothioureas as a novel class of gastric H(+) /K(+) -ATPase inhibitors.  

Science.gov (United States)

To find new H(+) /K(+) -ATPase inhibitors for the treatment of peptic ulcer disease, a series of novel N-aryl isothiourea derivatives were synthesized and their structures were identified by (1) H NMR and GC-MS. The effects of these compounds on inhibiting gastric acid secretion were evaluated by the guinea pig stomach mucous membrane study with pantoprazole magnesium as a positive control. The results showed that, of the 37 N-aryl isothiourea compounds synthesized, 20 compounds have comparable or stronger gastric acid inhibitory activities than that of pantoprazole magnesium. The quantitative structure-activity relationships (QSARs) of the N-aryl isothiourea compounds were also studied by comparative molecular field analysis (CoMFA) computation, and the model structure that was supposed to give more powerful bioactivities was finally predicted. PMID:24301963

Ma, Chao; Wu, Anhui; Wu, Yongqi; Ren, Xuhong; Cheng, Maosheng

2013-12-01

160

Microwave-assisted synthesis of C-8 aryl and heteroaryl inosines and determination of their inhibitory activities against Plasmodium falciparum purine nucleoside phosphorylase.  

Science.gov (United States)

8-Arylinosines have been scarcely studied for therapeutic purposes, probably due to difficulties in their synthesis. The recently described direct arylation reaction at position 8 of purine nucleosides has been employed to synthesize a series of 8-aryl and 8-pyridylinosines. These compounds have been studied for hydrolytic stability and subjected to biological evaluation. Three compounds have shown a pronounced specific inhibition of Plasmodium falciparum-encoded purine nucleoside phosphorylase, an important target for antimalarial chemotherapy. PMID:24929343

Gigante, Alba; Priego, Eva-María; Sánchez-Carrasco, Paula; Ruiz-Pérez, Luis Miguel; Vande Voorde, Johan; Camarasa, María-José; Balzarini, Jan; González-Pacanowska, Dolores; Pérez-Pérez, María-Jesús

2014-07-23

 
 
 
 
161

Antileishmanial, Antimicrobial and Antifungal Activities of Some New Aryl Azomethines  

Directory of Open Access Journals (Sweden)

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

162

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

163

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

164

Synthesis and antiproliferative studies of 5-aryl-2-(3-thienylamino)-1,3,4-thiadiazoles.  

Science.gov (United States)

A series of 5-aryl-2-(3-thienylamino)-1,3,4-thiadiazoles 3a-m were synthesized in good yields in two steps starting from thiophen-3-isothiocyanates. Those compounds as well as the thiosemicarbazide intermediates 2a-m were screened for their antiproliferative activity against a panel of six cancer cell lines. Among them, two 5-aryl-2-(3-thienylamino)-1,3,4-thiadiazoles (3f and 3i) have shown very interesting results with IC50 <10?M on three cell lines. PMID:24815511

Revelant, Germain; Gadais, Charlène; Mathieu, Véronique; Kirsch, Gilbert; Hesse, Stéphanie

2014-06-15

165

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

Energy Technology Data Exchange (ETDEWEB)

An efficient, regioselective synthesis of some 2-aroylimino-3-aryl-thiazolidin-4-ones (2aj) involving base-catalyzed cyclization of 1-aroyl-3-aryl thioureas with chloroacetyl chloride in dioxane is reported. The structures were confirmed by spectroscopic data, elemental analyses and in one case (2j) by single crystal X-ray diffraction data. Compounds (2a-j) were assayed in vitro for their antimicrobial activity against Gram positive and Gram negative bacteria and were found to exhibit promising activity towards the tested microorganisms, comparable to and in some cases better than those of the standard drugs. (author)

Saeed, Aamer; Abbas, Naeem [Quaid-I-Azam University, Islamabad (Pakistan). Dept. of Chemistry]. E-mail: aamersaeed@yahoo.com; Floerke, Ulrich [Universitat Paderborn (Germany). Fakultat fur Naturwissenschaften. Dept. de Chemie

2007-07-01

166

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

International Nuclear Information System (INIS)

An efficient, regioselective synthesis of some 2-aroylimino-3-aryl-thiazolidin-4-ones (2aj) involving base-catalyzed cyclization of 1-aroyl-3-aryl thioureas with chloroacetyl chloride in dioxane is reported. The structures were confirmed by spectroscopic data, elemental analyses and in one case (2j) by single crystal X-ray diffraction data. Compounds (2a-j) were assayed in vitro for their antimicrobial activity against Gram positive and Gram negative bacteria and were found to exhibit promising activity towards the tested microorganisms, comparable to and in some cases better than those of the standard drugs. (author)

167

Direct, metal-free amination of heterocyclic amides/ureas with NH-heterocycles and N-substituted anilines in POCl3.  

Science.gov (United States)

A POCl(3)-mediated, direct amination reaction of heterocyclic amides/ureas with NH-heterocycles or N-substituted anilines is described. Compared to the existing methods, this operationally simple protocol provides unique reactivity and functional group compatibility because of the metal-free, acidic reaction conditions. The yields are generally excellent. PMID:21899258

Deng, Xiaohu; Roessler, Armin; Brdar, Ivana; Faessler, Roger; Wu, Jiejun; Sales, Zachary S; Mani, Neelakandha S

2011-10-21

168

Radioiodination of Aryl-Alkyl Cyclic Sulfates  

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Full Text Available Among the currently available positron emitters suitable for Positron Emission Tomography (PET, 124I has the longest physical half-life (4.2 days. The long half-life and well-investigated behavior of iodine in vivo makes 124I very attractive for pharmacological studies. In this communication, we describe a simple yet effective method for the synthesis of novel 124I labeled compounds intended for PET imaging of arylsulfatase activity in vivo. Arylsulfatases have important biological functions, and genetic deficiencies of such functions require pharmacological replacement, the efficacy of which must be properly and non-invasively evaluated. These enzymes, even though their natural substrates are mostly of aliphatic nature, hydrolyze phenolic sulfates to phenol and sulfuric acid. The availability of [124I]iodinated substrates is expected to provide a PET-based method for measuring their activity in vivo. The currently available methods of synthesis of iodinated arylsulfates usually require either introducing of a protected sulfate ester early in the synthesis or introduction of sulfate group at the end of synthesis in a separate step. The described method gives the desired product in one step from an aryl-alkyl cyclic sulfate. When treated with iodide, the source cyclic sulfate opens with substitution of iodide at the alkyl center and gives the desired arylsulfate monoester.

Mikhail I. Papisov

2012-11-01

169

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 applied–ve 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 applied–ve field and to release the metal ion on stepping the potential to zero

170

Exploring structural requirements of 1-N-substituted thiocarbamoyl-3-phenyl-2-pyrazolines as antiamoebic agents using comparative QSAR modelling.  

Science.gov (United States)

Amoebiasis is a potentially lethal disease and causes 70,000 deaths per year. To find structural requirements for more active antiamoebic agents than metronidazole, comparative QSAR modelling was done on thirty 1-N-substituted thiocarbamoyl-3-phenyl-2-pyrazolines. The best model was obtained by using PLS technique with R(A)(2) and R(CV)(2) value of 88.50% and 82.90%, respectively. Amoebicidal activity may increase when Wang-Ford charges at atom numbers 6 and 12 have large positive values. Number of six-membered ring and sum of Kier-Hall electrotopological states may also increase amoebicidal activity when these have large positive values. Increasing value of rotatable bond fraction, approximate surface area and mean atomic polarizability scaled on carbon atom may be detrimental for antiamoebic activity. Decrease in values of electrostatic potential charges at atom numbers 1 and 12 may be conducive for activity. Electrophilic attacks may be favourable at these positions. PMID:20561784

Adhikari, Nilanjan; Maiti, Milan Kumar; Jha, Tarun

2010-07-15

171

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

International Nuclear Information System (INIS)

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

172

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

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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. What’s more, it is also a key intermediate for the synthesis of arylglyoxals.

Zhiling Cao

2013-12-01

173

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

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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. What’s 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

174

Synthesis of thiophene-based TAK-779 analogues by C-H arylation.  

Science.gov (United States)

A rapid synthesis of thiophene-based TAK-779 analogues 1 is reported using a late-stage diversification strategy. At the end of the synthesis, the key building block 2, which was prepared in six steps from thiophene, was arylated regioselectively at the ?-position directly with iodoarenes. Since 2 offers several reactive positions, various established catalyst systems were tested. It was found that Crabtree catalyst (an Ir catalyst) converted efficiently and selectively the thiophene system 2 into 2-aryl-substituted compounds 9. The direct C-H arylation of 2 with electron-rich iodoarenes led to high yields, whereas electron-deficient iodoarenes required longer reaction times for complete conversion. A small set of diverse amides 1 was synthesized by hydrolysis of 9 and subsequent HATU coupling with primary amines 4. PMID:23642160

Junker, Anna; Yamaguchi, Junichiro; Itami, Kenichiro; Wünsch, Bernhard

2013-06-01

175

Synthesis and anticancer activity of new 2-aryl-4h-3,1-benzothiazines.  

Science.gov (United States)

New compounds of 2-aryl-4H-3,1-benzothiazine set were synthesized and tested for their antiproliferative activity as part of our research in the antitumor field. The title compounds were obtained by the reaction of aryl-modified sulfinylbis((2,4-dihydroxyphenyl)methanethione) with 2-aminobenzyl alcohols. The reaction proceeded through thiobenzanilide intermediates, which were converted to the 4H-3,1-benzothiazine fused ring by an endocyclization process. The structures of compounds were identified from elemental, IR, (1) H-NMR, (13) C-NMR, and MS spectra analyses. The cytotoxicity in vitro against four human cancer cell lines was determined. The antiproliferative properties of some compounds were more beneficial than cisplatin studied comparatively. PMID:21469171

Niewiadomy, Andrzej; Matysiak, Joanna; Karpi?ska, Monika M

2011-04-01

176

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

177

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

International Nuclear Information System (INIS)

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

178

Synthesis, structure, and bioactivity of N'-substituted benzylidene-3,4,5-trimethoxybenzohydrazide and 3-acetyl-2-substituted phenyl-5-(3,4,5-trimethoxyphenyl)-2,3-dihydro-1,3,4-oxadiazole derivatives.  

Science.gov (United States)

Some 3-acetyl-2-substituted phenyl-5-(3,4,5-trimethoxyphenyl)-2,3-dihydro-1,3,4-oxadiazole derivatives were synthesized by cyclization reaction of N'-substituted benzylidene-3,4,5-trimethoxybenzohydrazide in acetic anhydride. Their structures were verified by elemental analysis, IR, (1)H NMR, and (13)C NMR. Compound 3i was provided with X-ray crystallographic data. The compounds were evaluated for their antiproliferative activities against some cancer cells in vitro by MTT method. Among them, 2a, 2b, 2c, 2f, 3l, and 3m were highly effective against PC3 cells and 2a, 2c, and 2f showed moderate activities against Bcap37 and BGC823 cells. The IC(50) values of high active compounds 2a, 2b, 2c, 2f, 3l, and 3m against PC3 cells were 0.2, 1.8, 0.2, 1.2, 1.7, and 0.3muM, respectively. PMID:16876405

Jin, Linhong; Chen, Jiang; Song, Baoan; Chen, Zhuo; Yang, Song; Li, Qianzhu; Hu, Deyu; Xu, Ruiqing

2006-10-01

179

On-surface aryl-aryl coupling via selective C-H activation.  

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Through the interplay of high-resolution scanning tunneling microscopy (STM) imaging/manipulation and density functional theory (DFT) calculations, we have demonstrated that an unprecedented selective aryl-aryl coupling via direct C-H bond activation can be successfully achieved on Cu(110). These findings present a simple and generalized route for preparing low dimensional carbon nanomaterials. PMID:25156416

Sun, Qiang; Zhang, Chi; Kong, Huihui; Tan, Qinggang; Xu, Wei

2014-09-11

180

Cobalt-catalyzed ortho-arylation of aromatic imines with aryl chlorides.  

Science.gov (United States)

An ortho-arylation reaction of aromatic imines with aryl chlorides has been achieved using a cobalt-N-heterocyclic carbene catalyst in combination with a neopentyl Grignard reagent. The reaction takes place at room temperature to afford biaryl products in moderate to good yields. PMID:22873283

Gao, Ke; Lee, Pin-Sheng; Long, Chong; Yoshikai, Naohiko

2012-08-17

 
 
 
 
181

Synthesis and antiplatelet evaluation of novel aryl-sulfonamide derivatives, from natural safrole.  

Science.gov (United States)

In the scope of a research program aiming at the synthesis and pharmacological evaluation of novel possible antiplatelet prototype compounds, exploring bioisosterism principles for molecular design, we describe in this paper the synthesis of new aryl-sulfonamides derivatives, structurally similar to known thromboxane A2 receptor antagonists. The synthetic route used to access the new compounds described herein starts from safrole, an abundant Brazilian natural product, which occurs in Sassafras oil (Ocotea pretiosa). The results from preliminary evaluation of these novel aryl-sulfonamide compounds by the platelet aggregation inhibitory test, using rabbit PRP, induced by ADP, collagen, arachidonic acid, and U46619, identified the N-[2-(4-carboxymethoxyphenyl)ethyl]-6-methyl-3,4-methylenedioxyphe nyl- sulfonamido derivative as the most active among them, presenting in IC50 value for the U-46619-induced platelet aggregation in rabbit platelet-rich plasma: 329 microM. PMID:10443173

Lima, L M; Ormelli, C B; Brito, F F; Miranda, A L; Fraga, C A; Barreiro, E J

1999-06-01

182

Dioxides of diphosphines as extractants for actinoid extraction. On effect of anomalous aryl strengthening  

International Nuclear Information System (INIS)

Investigations on the extraction of mineral acids, actinides and lanthanides by diphosphine dioxides of different structure are generalized. It is found that during extraction of actinides and lanthanides (3, 4, 6), accompanied by bidentate coordination, the effect of anomalous aryl strengthening of the complexes is detected: when electronegative aryl groups are introduced into methylenediphosphine dioxide molecule the dioxide basicity decreases, and the strength of the complexes, inspite of established regularities, increases considerably. It is found that due to the anomaly the extraction of actinides (3, 4, 6) increases by a factor of 150 per two aryl groups and by a factor of 2x104 - per four ones. Electron density transfer from phenyl groups to the main cycle of the complex, increase in the main solvate number and, very likely, the cycle aromatization are the reasons for the effect. High extractivity of bidentate organic phosphorus compounds and carbamoylphosphine oxides, conditioned by the effect of anomalous aryl strength ening, relatively weak dependence of distribution coefficien ts on acidity permit to extract actinides from aqueous solut ions of practically any com position without special preparat ion. Bad compatibility of t he extractants with hydrocarbon diluents, which is the main di fficulty of the process, can be overcome by the introducti o n of sufficiently long hydrocarbon radicals into phenyl rin g, by the use of solubilization by tributylphosphate and oth er compounds

183

Synthesis and bioactivity of 4-alkyl(aryl)thioquinazoline derivatives.  

Science.gov (United States)

Some S'-substituted 4-alkyl(aryl)thioquinazoline derivatives were synthesized through thioetherification reaction of 4-chloroquinazolines 2 and thiol compounds 1 refluxed in acetone in the presence of K(2)CO(3). Their structures were verified by elemental analysis, IR, (1)H NMR, and (13)C NMR. The compounds were evaluated for their anti-proliferative activities against some cancer cells in vitro by MTT method. Among them, 3c, 3a, 3d, 3f, and 3l were highly effective against PC3 cells and 3a-3m showed weak activities against Bcap37 and BGC823 cells. The IC(50) value of 3c, 3a, 3d, 3f, and3l against PC3 cell was 1.8, 5.6, 8.1, 8.7, and 8.9 microM, respectively. PMID:17317179

Yang, Song; Li, Zhi; Jin, Linhong; Song, Baoan; Liu, Gang; Chen, Jiang; Chen, Zhuo; Hu, Deyu; Xue, Wei; Xu, Ruiqing

2007-04-15

184

Unusual inner C-alkylation of 2-N-substituted N-confused porphyrin cobalt complexes in toluene and p-xylene.  

Science.gov (United States)

The inner C-benzyl- and C-p-xylyl-substituted cobalt(II) complexes of a 2-N-substituted N-confused porphyrin were synthesized from the reaction of 2-NCH2COOCH2C6H5NCTPPH (1) and CoCl2·6H2O in toluene (or p-xylene), and the structures were revealed by single-crystal X-ray analysis. PMID:24016258

Wang, Yu-Cheng; Chen, Jyh-Horung; Wang, Shin-Shin; Tung, Jo-Yu

2013-10-01

185

Selective arylation reactions of bismuth-transition metal salicylate complexes.  

Science.gov (United States)

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

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

2009-07-20

186

The effects of H-F and H-D substitutions on Jahn-Teller effects and charge transfer in the monocations of B, N-substituted acenes  

International Nuclear Information System (INIS)

The effects of H-D and H-F substitution on the electron-phonon interactions in the monocations of B, N-substituted acenes are studied. The B-N stretching modes around 1400 cm-1 afford large electron-phonon coupling constants in the monocations of B3N3F6 (1f) and B5N5F8 (2f). The total electron-phonon coupling constants for the monocations (l HOMO) are 0.479 and 0.402 eV in 1f and 2f, respectively. The l HOMO values become much larger by H-F substitution than by H-D substitution in the monocations of B, N-substituted acenes. The reason for the calculational results are discussed in detail in view of the phase patterns of the frontier orbitals and the vibronic active modes. The effects of H-D and H-F substitution on the charge transfer in the positively charged B, N-substituted acenes are also discussed

187

The Effect of the 3- and 4-Methyl Groups on the Opioid Receptor Properties of N-Substituted trans-3,4-dimethyl-4-(3-hydroxyphenyl)piperidines  

Science.gov (United States)

N-substituted trans-3,4-dimethyl-4-(3-hydroxyphenyl)piperidines (2a–b) are opioid receptor antagonists where the antagonist properties are not due to the type of N-substituent. In order to gain a better understanding of the contribution that the 3- and 4-methyl groups make to the pure antagonist properties of 2a–b, we synthesized analogues of 2a–b which lacked the 4-methyl (5a–b), 3-methyl (6a–b) and both the 3- and 4-methyl group (7a–b) and compared their opioid receptor properties. We found that (1) all N-methyl and N-phenylpropyl substituted compounds were non-selective opioid antagonists (2) all N-phenylpropyl analogues were more potent than their N-methyl counterparts and (3) compounds 2a–b which have both a 3- and 4-methyl substituent, were more potent antagonists than analogs 5a–b, 6a–b and 7a–b. We also found that the removal of 3-methyl substituent of N-methyl and N-phenylpropyl 3-methyl-4-(3-hydroxyphenyl)piperazines (8a–b) gives (4a–b) which are opioid antagonists. PMID:24635568

Kormos, Chad M.; Cueva, Juan Pablo; Gichinga, Moses G.; Runyon, Scott P.; Thomas, James B.; Brieaddy, Lawrence E.; Mascarella, S. Wayne; Gilmour, Brian P.; Navarro, Hernán A.; Carroll, F. Ivy

2014-01-01

188

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

189

Transition-metal-free highly chemo- and regioselective arylation of unactivated arenes with aryl halides over recyclable heterogeneous catalysts.  

Science.gov (United States)

A novel heterogeneous catalysis system using metal-organic frameworks as catalyst demonstrated excellent chemo- and regioselectivity for the direct arylation of unactivated arenes with aryl iodides/bromides without the assistance of any transition metals. PMID:22227601

Liu, Hongli; Yin, Biaolin; Gao, Zhiqiang; Li, Yingwei; Jiang, Huanfeng

2012-02-14

190

Synthesis of 1-acetyl-3-(2-thienyl)-5-aryl-2-pyrazoline derivatives and evaluation of their anticancer activity.  

Science.gov (United States)

In the present study, 1-acetyl-3-(2-thienyl)-5-aryl-2-pyrazoline derivatives (1-6) were synthesized via the ring closure reaction of 1-(2-thienyl)-3-aryl-2-propen-1-ones with hydrazine hydrate in acetic acid. The chemical structures of the compounds were elucidated by IR, (1)H-NMR, (13)C-NMR and mass spectral data and elemental analyses. MTT assay, analysis of DNA synthesis and caspase-3 activation assay were carried out to determine anticancer effects of the compounds on A549 and C6 cancer cell lines. They exhibited dose-dependent anticancer activity against A549 and C6 cancer cell lines. Anticancer activity screening results revealed that compounds 1, 2 and 4 were the most potent derivatives among these compounds. But anticancer effects of these compounds may result from different death mechanisms in A549 and C6 cell lines. PMID:23020635

Özdemir, Ahmet; Alt?ntop, Mehlika Dilek; Kaplanc?kl?, Zafer As?m; Turan-Zitouni, Gülhan; Ciftçi, Gül?en Akal?n; Y?ld?r?m, Safak Ulusoylar

2013-12-01

191

SYNTHESIS AND ANTIMICROBIAL EVALUATION OF 2-(4-FLUORO BENZYLTHIO)-N-(SUBSTITUTED PHENYL)PYRIMIDINE-4-AMINES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reaction of 4-fluorobenzylchloride with 2-thiouracil (1) gave 2-(4-fluorobenzylthio)pyrimidin-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 compound...

N M Goudgaon, Y. Rohini Reddy And B. U. Sheshikant

2013-01-01

192

Palladium-catalyzed debenzylative cross-coupling of aryl benzyl sulfides with aryl bromides: synthesis of diaryl sulfides.  

Science.gov (United States)

A novel debenzylative approach to synthesize diaryl sulfides from aryl benzyl sulfides and aryl bromides in good to excellent yields is reported. Mechanistic studies suggest a single catalyst, derived from Pd(dba)2 and NiXantPhos, efficiently catalyzes ?-arylation of sulfides, C-S bond cleavage, and C-S bond formation in a tricatalytic cycle. PMID:25298227

Mao, Jianyou; Jia, Tiezheng; Frensch, Gustavo; Walsh, Patrick J

2014-10-17

193

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

Directory of Open Access Journals (Sweden)

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

Deshmukh M

2010-01-01

194

Synthesis of 2-Amino-5-aryl-5,6-dihydro-7-(naphthalen-2-yl Quinazolin-4-ols  

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Full Text Available Quinazolines exhibit various biological activities. In the present investigation a series of new 2-amino-5-aryl-5,6-dihydro- 7-(naphthalen-2-ylquinazolin-4-ols are synthesized by the condensation of various naphthyl substitutedcyclohexenones with guanidine in presence of NaOEt. All the synthesized compounds are characterized by variousspectral techniques.

S. Senguttuvan

2010-01-01

195

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

Scientific Electronic Library Online (English)

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

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

196

Photochemistry of fluorinated aryl azides in toluene solution and in frozen polycrystals  

Energy Technology Data Exchange (ETDEWEB)

Several fluorinated triplet aryl nitrenes have been generated in low-temperature polycrystals by photolysis of the corresponding azides. Upon extended photolysis at {minus}196{degree}C the nitrenes abstract hydrogen from frozen toluene to give anilino-benzyl radical pairs, which subsequently combine to give CH insertion products. The radical pairs and the triplet nitrenes have been detected by EPR. In toluene solution, the major reaction products are tar, the corresponding fluorinated anilines, and azo compounds.

Leyva, E.; Munoz, D.; Platz, M.S. (Ohio State Univ., Columbus (USA))

1989-12-08

197

Electron impact induced fragmentation of 1-aryl-5-hydroxy-1,2,3,-triazole-4-carboxamides  

International Nuclear Information System (INIS)

The pathways of the electron impact induced fragmentation of 1-aryl-5-hydroxy-1,2,3-triazole-4-carboxamides were studied. The compositions of the key ions were confirmed by high-resolution mass spectrometry. The proposed pathways were established from mass analysed ion kinetic energy spectra, and B/E and B2/E linked scans. A variety of structures for the moleuclar ion of this compounds is proposed. 8 refs., 1 tab., 1 fig., ill

198

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 BF3·OEt2, 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

199

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

200

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

 
 
 
 
201

Coordination modes vs. antitumor activity: synthesis and antitumor activity of novel platinum(II) complexes of N-substituted amino dicarboxylic acids.  

Science.gov (United States)

The trans-(+/-)-1,2-diaminocyclohexaneplatinum(II) complexes of multidentate L-glutamate (Glu) and L-aspartate (Asp) were prepared and their antitumor activity was examined in relation with their coordination modes. All these complexes were obtained as a mixture of (O,O')- and (O,N)-chelate isomers due to rapid isomerization of the initially formed (O,O')-isomer to the thermodynamically more stable (O,N)-isomer. The (O,O')/(O,N)-isomeric mixture with the mole ratio of 80/20 exhibited excellent antitumor activity while the pure (O,N)-isomer was only marginally active. Therefore, in order to prevent the linkage isomerization of the active (O,O')-isomer to the inactive (O,N)-isomer, we have designed N-substituted amino dicarboxylic acids as a leaving group and prepared a new series of complexes, [Pt(dach)(RGlu)] and [Pt(dach)(RAsp)] (dach=trans-(+/-)-1,2-diaminocyclohexane; R=acetyl (Ac), propionyl (Pro), pivaloyl (Piv), carbobenzyloxy (Cbz) or phthaloyl (Phth)) and characterized by means of elemental analyses, and 1H NMR, 195Pt NMR and IR spectroscopies. The N-substituted amino dicarboxylate ligands were found to coordinate to platinum(II) ion through only the (O,O')-chelation mode, and their Pt(II) complexes were chemically stable in aqueous solution. The present Pt(II) complexes of N-substituted amino dicarboxylic acids showed excellent antitumor activity against both murine leukemia L1210 and human tumor cells. Especially, the highly hydrophobic N-phthaloylglutamate complex, [Pt(dach)(PhthGlu)], exhibited an outstanding in vitro activity (IC50=2.22 microM) on the human stomach cancer cells which are not responsive to cisplatin and carboplatin. PMID:14659638

Kim, Yeong-Sang; Song, Rita; Chung, Hyun Cheol; Jun, Moo Jin; Sohn, Youn Soo

2004-01-01

202

Aryl Polyphosphonates: Useful Halogen-Free Flame Retardants for Polymers  

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

Li Chen

2010-10-01

203

Gas chromatographic retention indices for N-substituted amino s-triazines on capillary columns. Part V. Temperature dependence of the retention index  

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Full Text Available The temperature dependence of the retention index was studied for N-substituted amino s-triazines on DB-1, DB-5 and DB-WAX capillary columns within the temperature range 190?230ºC. Two linear equations with the column temperature and its reciprocal as variables were studied. The first one shows a slightly better precision for 2,4-bis(alkylamino-6-chloro-s-triazines and 2-alkylamino-4,6-dichloro-s-triazines, while the second one shows a better precision for 2,4-bis(cycloalkylamino-6-chloro-s-triazines.

DUSAN Z. MIJIN

2003-11-01

204

Gas chromatographic retention indices for N-substituted amino s-triazines on capillary columns. Part V. Temperature dependence of the retention index  

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The temperature dependence of the retention index was studied for N-substituted amino s-triazines on DB-1, DB-5 and DB-WAX capillary columns within the temperature range 190?230ºC. Two linear equations with the column temperature and its reciprocal as variables were studied. The first one shows a slightly better precision for 2,4-bis(alkylamino)-6-chloro-s-triazines and 2-alkylamino-4,6-dichloro-s-triazines, while the second one shows a better precision for 2,4-bis(cycloalkylamino)-6-chloro...

Mijin, Dusan Z.; Antonovic, Dusan G.; Jovanovic, Bratislav Z.

2003-01-01

205

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

Science.gov (United States)

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

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

2014-02-12

206

New antithrombotic aryl-sulfonylthiosemicarbazide derivatives synthesized from natural safrole  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese No âmbito de uma linha de pesquisas que trata da síntese e avaliação farmacológica de novos candidatos a protótipos de agentes antitrombóticos, explorando a hibridação molecular como estratégia de planejamento estrutural, descrevemos neste trabalho a síntese e avaliação farmacológica de novas sulfon [...] ilsemicarbazidas (10a-d), planejadas por analogia estrutural a antagonistas de receptores de TXA2, utilizando o safrol (9), produto natural brasileiro abundante, isolado do óleo de Sassafrás, como matéria-prima sintética. A avaliação das propriedades antiagregantes plaquetárias das sulfonilsemicarbazidas (10a-d) no modelo induzido por ADP, colágeno, ácido araquidônico e U46619, permitiu evidenciar um importante perfil antitrombótico ao nível da cascata do ácido araquidônico para o derivado 6-metil-3,4-metilenodioxifenil-sulfonil-N-feniltiosemicarbazida (10d), que representa um novo protótipo de agentes anti-trombóticos. Abstract in english As part of a research program aiming at the synthesis and pharmacological evaluation of novel lead-compounds exploring Brazilian abundant natural products, we describe herein the synthesis and the antithrombotic profile of new aryl-sulfonylsemicarbazides and aryl-sulfonylthiosemicarbazides (10a-d). [...] The new derivatives, designed with basis on the molecular hybridization concept, were prepared in good yields from natural safrole (9), isolated from sassafras oil. The anti-aggregating activity of these new derivatives (10a-d) on platelet aggregation induced by ADP, collagen, arachidonic acid and U-46619, indicates an important antithrombotic profile for the 6-methyl-3,4-methylenedioxyphenyl-sulfonyl-N-phenylthiosemicarbazide derivative (10d), acting at the arachidonic acid cascade and representing a new lead-compound with antithrombotic activity.

Lídia M., Lima; Claudia B., Ormelli; Carlos A.M., Fraga; Ana L.P., Miranda; Eliezer J., Barreiro.

207

Synthesis of novel pyrazolic analogues of chalcones and their 3-aryl-4-(3-aryl-4,5-dihydro-1H-pyrazol-5-yl)-1-phenyl-1H-pyrazole derivatives as potential antitumor agents.  

Science.gov (United States)

Novel (E)-1-aryl-3-(3-aryl-1-phenyl-1H-pyrazol-4-yl)prop-2-en-1-ones 5/6 (pyrazolic chalcones) were synthesized from a Claisen-Schmidt reaction of 3-aryl-1-phenylpyrazol-4-carboxaldehydes 4 with several acetophenone derivatives 1. Subsequently, the microwave-assisted cyclocondensation reaction of chalcones 5/6 with hydrazine afforded the new racemic 3-aryl-4-(3-aryl-4,5-dihydro-1H-pyrazol-5-yl)-1-phenyl-1H-pyrazoles 7 or their N-acetyl derivatives 8 and 9 when reactions where carried out in DMF or acetic acid, respectively. Several of these compounds were screened by the US National Cancer Institute (NCI) for their ability to inhibit 60 different human tumor cell lines, where 5c and 9g showed remarkable activity mainly against leukemia (K-562 and SR), renal cancer (UO-31) and non-small cell lung cancer (HOP-92) cell lines, with the most important GI50 values ranging from 0.04 to 11.4 microM, from the in vitro assays. PMID:20594863

Insuasty, Braulio; Tigreros, Alexis; Orozco, Fabián; Quiroga, Jairo; Abonía, Rodrigo; Nogueras, Manuel; Sanchez, Adolfo; Cobo, Justo

2010-07-15

208

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

Science.gov (United States)

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

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

1999-01-01

209

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.

210

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

211

Gas chromatograpic retention indices for N-substituted amino s-triazines on capillary columns. Part IV. Influence of column polarity on retention index  

Directory of Open Access Journals (Sweden)

Full Text Available The retention index increment for the addition of a methylene group to the alkyl group of an analyte molecule is shown to be lower than 100 i.u. for N-substituted amino s-triazines. In temperature progammed gas chromatography, a linearly interpolated retention index I, determined from the linear regression equation, I = AZ + (GRFz, with the number of atoms (Z in the molecule as variable, was used to describe the retention of 25 N-substituted amino s-triazines, on DB-1, DB-5 and DB-WAX capillary columns, divided into five series according to the similarity of the alkyl groups in the particular series. In the above equation, A is the linear regression coefficient or the retention index increment per atom addition, Z the number of C, N and Cl atoms in the molecule, and (GRFz the group retention factor or functionality constant for functional groups in the molecule, based on the number Z. It is possible to estimate the retention indices of an unknown member of the series from the Z, A and (GRF values.

OLGA S. RAJKOVIC

2003-07-01

212

Design, synthesis and histamine H1-receptor antagonistic activity of some novel 4-amino-2-(substituted)-5-(substituted) aryl-6-[(substituted aryl) amino] pyrimidines.  

Science.gov (United States)

A series of 4-amino-2-(substituted)-5-(substituted)aryl-6-[(substituted)aryl)-amino]pyrimidines was designed based on the triangular pharmacophoric requirements for histamine H1-receptor antagonists. The designed molecules were synthesized by condensation of arylacetonitriles with respective arylisothiocyanates to form corresponding acrylonitriles followed by cyclocondensation with carboxamidines to afford substituted pyrimidines. All compounds were screened for their histamine H1-receptor antagonistic activity using the model "Inhibition of the isotonic contraction induced by histamine on isolated guinea pig ileum". Target compounds were also evaluated for their sedative potential as well as their anticholinergic activities as these two are known to be the common adverse effects of histamine H1-receptor antagonists. Compounds 2h, 2i, 2j and 2k exhibited potent histamine H1-receptor antagonistic activity, which was found to be comparable with the standard drug, cetirizine (CAS 83881-51-0) and more potent than the conventional drug mepyramine (CAS 91-84-9). Some of the compounds have displayed very low sedative potential compared to diphenhydramine (CAS 58-73-1), but was found higher than cetirizine. None of them showed anticholinergic activity indicating potentialities of this series to be developed as second-generation histamine H1-receptor antagonists. PMID:19537525

Chhabria, Mahesh T; Patel, Vimal T; Rajan, Kombu S; Brahmkshatriya, Pathik S

2009-01-01

213

Discovery of N-Substituted Oseltamivir Derivatives as Potent and Selective Inhibitors of H5N1 Influenza Neuraminidase.  

Science.gov (United States)

To discover group-1-specific neuraminidase (NA) inhibitors that are especially involved in combating the H5N1 virus, two series of oseltamivir derivatives were designed and synthesized by targeting the 150-cavity. Among these, compound 20l was the most potent N1-selective inhibitor, with IC50 values of 0.0019, 0.0038, and 0.0067 ?M against NAs from three H5N1 viruses. These values are better than those of oseltamivir carboxylate. Compound 32 was another potent N1-selective inhibitor that exhibited a 12-fold increase in activity against the H274Y mutant relative to oseltamivir carboxylate. Molecular docking studies revealed that the 150-cavity was an auxiliary binding site that may contribute to the high selectivity of these compounds. The present work is a significant breakthrough in the discovery of potent group-1-specific neuraminidase inhibitors, which may be further investigated for the treatment of infection by the H5N1 virus. PMID:25255388

Xie, Yuanchao; Xu, Dongqing; Huang, Bing; Ma, Xiuli; Qi, Wenbao; Shi, Fangyuan; Liu, Xinyong; Zhang, Yingjie; Xu, Wenfang

2014-10-23

214

Synthesis of N-substituted 3,5-bis(arylidene)-4-piperidones with high antitumor and antioxidant activity.  

Science.gov (United States)

A series of 3,5-bis(arylidene)-4-piperidone (DAP) compounds are considered as synthetic analogues of curcumin for anticancer properties. We performed structure-activity relationship studies by synthesizing a number of DAPs N-alkylated or acylated with nitroxides or their amine precursors as potent antioxidant moieties. Both subtituents on arylidene rings and on piperidone nitrogen (five- or six-membered, 2- or 3-substituted or 3,4-disubstituted isoindoline nitroxides) were varied. The anticancer efficacy of the new DAP compounds was tested by measuring their cytotoxicity to cancer cell lines A2780 and MCF-7 and to the H9c2 cell line. The results showed that all DAP compounds induced a significant loss of cell viability in the human cancer cell lines tested; however, only pyrroline appended nitroxides (5c (Selvendiran, K.; Tong, L.; Bratasz, A.; Kuppusamy, L. M.; Ahmed, S.; Ravi, Y.; Trigg, N. J.; Rivera, B. K.; Ka?lai, T.; Hideg, K.; Kuppusamy, P. Mol. Cancer Ther. 2010, 9, 1169-1179), 5e, 7, 9) showed limited toxicity toward noncancerous cell lines. Computer docking simulations support the biological activity tested. These results suggest that antioxidant-conjugated DAPs will be useful as a safe and effective anticancer agent for cancer therapy. PMID:21702507

Kálai, Tamás; Kuppusamy, M Lakshmi; Balog, Mária; Selvendiran, Karuppaiyah; Rivera, Brian K; Kuppusamy, Periannan; Hideg, Kálmán

2011-08-11

215

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

Science.gov (United States)

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

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

2013-11-01

216

Synthesis and antibacterial activities of acylide derivatives bearing an aryl-tetrazolyl chain  

Science.gov (United States)

Seventeen acylides bearing an aryl-tetrazolyl alkyl-substituted side chain were synthesized, starting from clarithromycin, via several reactions including hydrolysis, acetylating, esterification, carbamylation, and Michael addition. The structures of all new compounds were confirmed by 1H nuclear magnetic resonance spectroscopy, 13C nuclear magnetic resonance spectroscopy, and mass spectrometry. All these synthesized acylides were evaluated for in vitro antimicrobial activities against gram-positive pathogens (Staphylococcus aureus, Staphylococcus epidermidis) and gram-negative pathogens (Pseudomonas aeruginosa, Escherichia coli), using the broth microdilution method. Results showed that compounds 10e, 10f, 10g, 10 h, 10o have good antibacterial activities.

Shan, Ling-Xing; Sun, Ping-Hua; Guo, Bao-Qin; Xu, Xing-Jun; Li, Zhi-Qiang; Sun, Jia-Zhi; Zhou, Shu-Feng; Chen, Wei-Min

2014-01-01

217

Synthesis and bioactivities of 6,7,8-trimethoxy-N-aryl-4-aminoquinazoline derivatives.  

Science.gov (United States)

A series of 4-aminoquinazoline derivatives is prepared by the nucleophilic substitution reaction of 6,7,8-trimethoxy-4-chloroquinazoline and aryl amine. The structures of the compounds are confirmed by elemental analysis, IR, and (1)H NMR spectral data. The compounds are also evaluated for their ability to inhibit tumor cells PC3, A431, Bcap-37, and BGC823 by MTT assays. Among them, 6b and 6e are found as potent inhibitors, with IC(50) values ranging from 5.8 to 9.8microM, in vitro assay. PMID:17681471

Liu, Gang; Hu, De-Yu; Jin, Lin-Hong; Song, Bao-An; Yang, Song; Liu, Ping-Shen; Bhadury, Pinaki S; Ma, Yao; Luo, Hui; Zhou, Xian

2007-10-15

218

PALLADIUM CATALYZED COUPLING OF ARYL HALIDES WITH ARYLHALOSILANES IN AIR AND WATER. (R828129)  

Science.gov (United States)

In the presence of a palladium catalyst, various aryl halides reacted with arylhalosilanes in aqueous media and under an air atmosphere to give the corresponding unsymmetrical aryl–aryl coupling products conveniently. ...

219

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

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

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

1980-10-01

220

Direct arylation of N-heteroarenes with aryldiazonium salts by photoredox catalysis in water.  

Science.gov (United States)

A highly effective visible light-promoted "radical-type" coupling of N-heteroarenes with aryldiazonium salts in water has been developed. The reaction proceeds at room temperature with [Ru(bpy)3 ]Cl2 ?6?H2 O as a photosensitizer and a commercial household light bulb as a light source. Pyridine and a variety of substituted pyridines are effective substrates under these reaction conditions, and only monosubstituted products are formed with different regioselectivities. Using aqueous formic acid as solvent, an array of xanthenes, thiazole, pyrazine, and pyridazine are compatible with this new arylation approach. The broad substrate scope, mild reaction conditions, and use of water as reaction solvent make this procedure a practical and environmentally friendly method for the synthesis of compounds containing aryl-heteroaryl motifs. PMID:24500947

Xue, Dong; Jia, Zhi-Hui; Zhao, Cong-Jun; Zhang, Yan-Yan; Wang, Chao; Xiao, Jianliang

2014-03-01

 
 
 
 
221

Synthesis and fungicidal activity of novel chloro-containing 1-aryl-3-oxypyrazoles with an oximino ester or oximino amide moiety.  

Science.gov (United States)

Six novel chloro-containing 1-aryl-3-oxypyrazoles TMa-TMf with an oximino ester or an oximino amide moiety were prepared by the reaction of 1-aryl-1H-pyrazol-3-ols with benzyl bromide. Their structures were characterized by 1H-NMR, 13C-NMR, IR, MS, and elemental analysis. A preliminary in vitro bioassay indicated that compounds TMa, TMe and TMf displayed excellent fungicidal activity against Rhizoctonia solani and could be used as potential lead compounds for further development of novel fungicides. PMID:24941339

Liu, Yuanyuan; Li, Yi; Chen, Nanqing; Lv, Kunzhi; Zhou, Chao; Xiong, Xiaohui; Li, Fangshi

2014-01-01

222

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

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

Karigar Asif A.

2011-01-01

223

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

Science.gov (United States)

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

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

2013-04-19

224

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

225

Synthesis, crystal structure and anti-HIV activity of 2-adamantyl/adamantylmethyl-5-aryl-1,3,4-oxadiazoles.  

Science.gov (United States)

Two series of 2-adamantyl/adamantylmethyl-5-aryl-1,3,4-oxadiazoles (4a-l and 5a-l) were synthesized by cyclodehydration of adamantan-1-carboxylic acid/adamantylacetic acid with various aryl hydrazides (3a-l) in the presence of POCl(3). The synthesis was supported by spectroanalytical techniques and verified further by crystal structure determination of compounds 4e and 5k. The synthesized compounds were screened for their inhibitory activity against HIV-1 and HIV-2 in MT-4 cells. Compound 5b exhibited a moderate activity in vitro for the replication of both virus types, suggesting for further structural modification as a new lead in the development of an antiviral agent. PMID:22741800

Khan, Mahmood-ul-Hassan; Akhtar, Tashfeen; Al-Masoudi, Najim A; Stoeckli-Evans, Helen; Hameed, Shahid

2012-11-01

226

Rh(I)-catalyzed direct arylation of azines.  

Science.gov (United States)

The Rh(I)-catalyzed direct arylation of azines has been developed. Quinolines and 2-substituted pyridines couple with aryl bromides to efficiently afford ortho-arylated azine products using the commercially available and air-stable catalyst [RhCl(CO)2]2. Electron-deficient and electron-rich aromatic bromides couple in good yields, and hydroxyl, chloro, fluoro, trifluoromethyl, ether, and ketone functionalities are compatible with the reaction conditions. Aroyl chlorides also serve as effective azine coupling partners to give ortho-arylation products via a decarbonylation pathway. PMID:21033740

Berman, Ashley M; Bergman, Robert G; Ellman, Jonathan A

2010-11-19

227

The synthesis of bisguanidinoalkanes and guanidinoalkanes, N- or N'-substitutes with pyrimidines, as analogues of chlorhexidine  

International Nuclear Information System (INIS)

A series of N,N''' -alkanediylbis[N'-(5-halopyrimidin-2-yl)guanidine] salts has been synthesized along with N,N'''-(trans-cyclohexane-1,4-diyl)bis[N'-(5-chloropyrimidin-2-yl)guanidine], N,N'''-(cis-cyclohexane-1,4-diyl)bis[N'-(5-chloropyrimidin-2-yl)guanidine] dihydrochloride and N-(cis-4-aminocyclohexan-1-yl)-N'-(5-chloropyrimidin-2-yl)guanidine dihydrochloride. Furthermore, a series of N-(alkan-1-yl)-N'-(5-chloropyrimidin-2yl)guanidine hydrochlorides and N-(6-aminohexan-1-yl)-N'-(5-chloropyrimidin-2-yl)guanidine dihydrochloride were synthesized. This series of compounds was prepared by displacement reactions of 2-methylsulfonylpyrimidines with bisguanidinoalkanes or by condensation of 5-chloro-2-cyanoaminopyrimidine (5-chloropyrimidin-2-ylcyanamide) with alkylamines. 19 refs

228

N-Heterocyclic carbene–palladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides  

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Full Text Available New Pd–NHC 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 Özdemir

2013-02-01

229

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

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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 C–N and C–O bond formation have been developed. The C–N 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 C–O 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

230

On solutions of organic strontium compounds  

International Nuclear Information System (INIS)

Preparation of a strontium-organic compound of the type ArSrI (where Ar is the aryl radical) in diethyl ether and benzene with a small addition of tetrahydrofurane (THF), sufficient for the formation of a complex of the composition ArSrIxTHF, is described. The synthesis is carried out in an argon atmosphere. The compounds synthesized react vigorously with atmospheric water and oxygen. The composition of the compounds was confirmed by means of reaction gas chromatography

231

Design, synthesis and evaluation of N-substituted saccharin derivatives as selective inhibitors of tumor-associated carbonic anhydrase XII.  

Science.gov (United States)

A series of N-alkylated saccharin derivatives were synthesized and tested for the inhibition of four different isoforms of human carbonic anhydrase (CA, EC 4. 2.1.1): the transmembrane tumor-associated CA IX and XII, and the cytosolic CA I and II. Most of the reported derivatives inhibited CA XII in the nanomolar/low micromolar range, hCA IX with KIs ranging between 11 and 390 nM, whereas they were inactive against both CA I (KIs >50 ?M) and II (K(I)s ranging between 39.1 nM and 50 ?M). Since CA I and II are off-targets of antitumor carbonic anhydrase inhibitors (CAIs), the obtained results represent an encouraging achievement for the development of new anticancer candidates without the common side effects of non-selective CAIs. Moreover, the lack of an explicit zinc binding function on these inhibitors opens the way towards the exploration of novel mechanisms of inhibition that could explain the high selectivity of these compounds for the inhibition of the transmembrane, tumor-associated isoforms over the cytosolic ones. PMID:24560739

D'Ascenzio, Melissa; Carradori, Simone; De Monte, Celeste; Secci, Daniela; Ceruso, Mariangela; Supuran, Claudiu T

2014-03-15

232

MICROWAVE ASSISTED SYNTHESIS OF 3-(2-BENZOYL-6-HYDROXY-3-METHYL BENZO[b] FURAN-5-YL)-5-(ARYL)-4, 5-DIHYDRO-1H-PYRAZOLE CARBOTHIOAMIDES AND THEIR ANTIBACTERIAL ACTIVITY Mikrowellen unterstützte Synthese von 3 - (2-Benzoyl-6-HYDROXY-3-METHYL Benzo [b] furan-5-yl) -5 - (ARYL) -4, 5-DIHYDRO-1H-pyrazol CARBOTHIOAMIDES UND ihre antibakterielle Aktivität  

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A series of 3-(2-Benzoyl-6-hydroxy-3-methyl benzo[b] furan-5-yl)-5-(aryl)-4, 5-dihydro-1Hpyrazole carbothioamides have been prepared by the reaction of (E)-1-(2-Benzoyl-6-hydroxy-3- methylbenzo[b]furan-5-yl)-3-aryl-2-propen-1-ones with thiosemicarbazide in the presence of sodium hydroxide under microwave irradiation. The structures of newly synthesized compounds have been confirmed on the basis of elemental analysis, IR,1H-NMR,13C-NMR and mass spectral data. All the compounds were screened fo...

Ashok D, Sudershan K.

2011-01-01

233

MICROWAVE ASSISTED SYNTHESIS OF 3-(2-BENZOYL-6-HYDROXY-3-METHYL BENZO[b] FURAN-5-YL-5-(ARYL-4, 5-DIHYDRO-1H-PYRAZOLE CARBOTHIOAMIDES AND THEIR ANTIBACTERIAL ACTIVITY Mikrowellen unterstützte Synthese von 3 - (2-Benzoyl-6-HYDROXY-3-METHYL Benzo [b] furan-5-yl -5 - (ARYL -4, 5-DIHYDRO-1H-pyrazol CARBOTHIOAMIDES UND ihre antibakterielle Aktivität  

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Full Text Available A series of 3-(2-Benzoyl-6-hydroxy-3-methyl benzo[b] furan-5-yl-5-(aryl-4, 5-dihydro-1Hpyrazole carbothioamides have been prepared by the reaction of (E-1-(2-Benzoyl-6-hydroxy-3- methylbenzo[b]furan-5-yl-3-aryl-2-propen-1-ones with thiosemicarbazide in the presence of sodium hydroxide under microwave irradiation. The structures of newly synthesized compounds have been confirmed on the basis of elemental analysis, IR,1H-NMR,13C-NMR and mass spectral data. All the compounds were screened for their antibacterial activity.

Ashok D, Sudershan K,Khalilullah M

2011-10-01

234

Anticonvulsant Profiles of Certain New 6-Aryl-9-substituted-6,9-diazaspiro-[4.5]decane-8,10-diones and 1-Aryl-4-substituted-1,4-diazaspiro[5.5]undecane-3,5-diones  

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Full Text Available Synthesis and anticonvulsant potential of certain new 6-aryl-9-substituted-6,9-diazaspiro[4.5]decane-8,10-diones (6a–l and 1-aryl-4-substituted-1,4-diazaspiro[5.5] undecane-3,5-diones (6m–x are reported. The intermediates 1-[(aryl(cyanomethylamino] cycloalkanecarboxamides (3a–f were prepared via adopting Strecker synthesis on the proper cycloalkanone followed by partial hydrolysis of the obtained nitrile functionality and subsequent N-cyanomethylation. Compounds 3a–f were subjected to complete nitrile hydrolysis to give the respective carboxylic acid derivatives 4a–f which were cyclized under mild conditions to give the spiro compounds 5a–f. Ultimately, compounds 5a–f were alkylated or aralkylated to give the target compounds 6a–i and 6m–u. On the other hand, compounds 6j–l and 6v–x were synthesized from the intermediates 5a–f through alkylation, dehydration and finally tetrazole ring formation. Anticonvulsant screening of the target compounds 6a–x revealed that compound 6g showed an ED50 of 0.0043 mmol/kg in the scPTZ screen, being about 14 and 214 fold more potent than the reference drugs, Phenobarbital (ED50 = 0.06 mmol/kg and Ethosuximide (ED50 = 0.92 mmol/kg, respectively. Compound 6e exhibited an ED50 of 0.019 mmol/kg, being about 1.8 fold more potent than that of the reference drug, Diphenylhydantoin (ED50 = 0.034 mmol/kg in the MES screen. Interestingly, all the test compounds 6a–x did not show any minimal motor impairment at the maximum administered dose in the neurotoxicity screen.

Mohamed N. Aboul-Enein

2014-09-01

235

Anticonvulsant Profiles of Certain New 6-Aryl-9-substituted-6,9-diazaspiro-[4.5]decane-8,10-diones and 1-Aryl-4-substituted-1,4-diazaspiro[5.5]undecane-3,5-diones  

Science.gov (United States)

Synthesis and anticonvulsant potential of certain new 6-aryl-9-substituted-6,9-diazaspiro[4.5]decane-8,10-diones (6a–l) and 1-aryl-4-substituted-1,4-diazaspiro[5.5]undecane-3,5-diones (6m–x) are reported. The intermediates 1-[(aryl)(cyanomethyl)amino]cycloalkanecarboxamides (3a–f) were prepared via adopting Strecker synthesis on the proper cycloalkanone followed by partial hydrolysis of the obtained nitrile functionality and subsequent N-cyanomethylation. Compounds 3a–f were subjected to complete nitrile hydrolysis to give the respective carboxylic acid derivatives 4a–f which were cyclized under mild conditions to give the spiro compounds 5a–f. Ultimately, compounds 5a–f were alkylated or aralkylated to give the target compounds 6a–i and 6m–u. On the other hand, compounds 6j–l and 6v–x were synthesized from the intermediates 5a–f through alkylation, dehydration and finally tetrazole ring formation. Anticonvulsant screening of the target compounds 6a–x revealed that compound 6g showed an ED50 of 0.0043 mmol/kg in the scPTZ screen, being about 14 and 214 fold more potent than the reference drugs, Phenobarbital (ED50 = 0.06 mmol/kg) and Ethosuximide (ED50 = 0.92 mmol/kg), respectively. Compound 6e exhibited an ED50 of 0.019 mmol/kg, being about 1.8 fold more potent than that of the reference drug, Diphenylhydantoin (ED50 = 0.034 mmol/kg) in the MES screen. Interestingly, all the test compounds 6a–x did not show any minimal motor impairment at the maximum administered dose in the neurotoxicity screen. PMID:25250910

Aboul-Enein, Mohamed N.; El-Azzouny, Aida A.; Attia, Mohamed I.; Maklad, Yousreya A.; Aboutabl, Mona E.; Ragab, Fatma; El-Hamid, Walaa H. A. Abd

2014-01-01

236

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

237

Aryl (meth)acrylates and polymers based on them  

International Nuclear Information System (INIS)

Data on the synthesis, polymerisation and copolymerisation of aryl (meth)acrylates are generalised and systematised. Chemical and photochemical properties of the polymers and copolymers are considered. Basic directions of practical application of poly[aryl (meth)acrylates] and copolymers are demonstrated. The bibliography includes 449 references.

238

QSAR Studies on N-aryl Derivative Activity Towards Alzheimer’s Disease  

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Full Text Available A Quantitative Structure Activity Relationship (QSAR study has been an attempted on a series of 88 N-aryl derivatives which display varied inhibitory activity towards both acetylcholinesterase (AChE and butyrylcholinesterase (BChE, targets in Alzheimer’s drug discovery. QSAR models were derived for 53 and 61 compounds for each target, respectively, with the aid of genetic function approximation (GFA technique using topological, molecular shape, electronic and structural descriptors. The predictive ability of the QSAR model was evaluated using a test set of 26 compounds for AChE (r2pred = 0.857, (q2 = 0.803 and 20 compounds for BChE (r2 pred = 0.882, (q2 = 0.857. The QSAR models point out that AlogP98, Wiener, Kappa-1-AM, Dipole-Mag, and CHI-1 are the important descriptors effectively describing the bioactivity of the compounds.

Kamalakaran Anand Solomon

2009-04-01

239

Phosphine catalyzed alpha-arylation of enones and enals using hypervalent bismuth reagents: regiospecific enolate arylation via nucleophilic catalysis.  

Science.gov (United States)

Exposure of enones and enals to 20 mol % tributylphosphine in the presence of triarylbismuth(V) dichlorides results in regiospecific aryl transfer to the alpha-position of the enone or enal pronucleophile. These results represent the first examples of enolate arylation under the conditions of nucleophilic catalysis. PMID:15113193

Koech, Phillip K; Krische, Michael J

2004-05-01

240

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

Science.gov (United States)

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

 
 
 
 
241

Boronated porphyrin compounds  

Science.gov (United States)

A compound is described having the structure ##STR1## where R preferably is ##STR2## and most preferably R.sup.3 is a closo-carborane and R.sup.2 is --H, an alkyl or aryl having 1 to about 7 carbon atoms, This invention was made with Government support under NIH Grant No. CA-37961 awarded by the Department of Health and Human Services and under the Associated Universities Inc. Contract No. De-AC02-76CH00016 with the U.S. Department of Energy. The Government has rights in this invention.

Kahl, Stephen B. (Portola Valley, CA); Koo, Myoung-Seo (San Francisco, CA)

1992-01-01

242

[Synthesis and choleretic activity of 3-(2-aryl-5R-benzimidazol-1-yl) butanoic acids].  

Science.gov (United States)

Thirty 3-(2-aryl-5R-benzimidazol-1-yl)butanoic acids were prepared in order to evaluate substitution effects on the 2 and 5 positions of the heterocyclic ring upon the previously recorded choleretic activity of 3-(2-phenylbenzimidazol-1-yl)butanoic acid. A general choleretic activity is shown by the acids tested, which in several cases it is superior to that of the model compound and sometimes also to that of dehydrocholic acid. PMID:3666121

Grella, G; Paglietti, G; Sparatore, F; Manca, P; Satta, M

1987-07-01

243

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

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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

244

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

Science.gov (United States)

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

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

2004-10-01

245

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

246

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

Science.gov (United States)

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

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

2010-12-15

247

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

Directory of Open Access Journals (Sweden)

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

Rafiuzzaman SaeedulHaq

2011-12-01

248

Photoinduced electron-transfer reactions of aryl glycosides  

Energy Technology Data Exchange (ETDEWEB)

The photolytic effects of ultraviolet, as well as other electromagnetic, radiation on carbohydrates are of interest in connection with photodegradation of cellulose and potential application in the photolytic cleavage of lignocellulosic bonds. Aryl glycosides, model compounds for lignocellulosic systems, were irradiated under conditions selected to achieve photoinduced electron-transfer. Various anomeric phenyl D-gluco- and D-galacto-pyranoside solutions in acetonitrile saturated with oxygen, air, or nitrogen and containing 1,4-dicyanonaphthalene (DCN) were irradiated at 350 nm for extended periods, and cleavage of the radical cation formed upon electron transfer to give the simple monosaccharide and phenol was observed. In the presence of methanol, it is possible to intercept the cationic intermediate, with formation of the corresponding methyl glycosides. Control experiments conducted in the presence of oxygen, air, or nitrogen in the absence of DCN showed little or no conversion. Comparison of the modes of fragmentation in solution with those observed in the gas phase upon electron impact in the mass spectrometer was made, and mechanisms for the reactions induced by electron transfer under these conditions are proposed.

Timpa, J.D.; Legendre, M.G.; Griffin, G.W.; Das, P.K.

1983-01-01

249

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

Science.gov (United States)

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

Mahiya, Kuldeep; Mathur, Pavan

2013-09-01

250

A large perturbation on electronic and photophysical properties of Ir(III) carbene complexes caused by the variation of N-substitution in N,N?-heteroaromatic ligands  

Science.gov (United States)

DFT/TDDFT investigation was performed on the electronic and photophysical properties of blue-emitting Ir(III) carbene complexes (fpmi)3-xIr(N^N?)x (x = 1, 2) [fpmi = 1-(4-fluorophenyl)-3-methylimidazolin-2-ylidene-C,C2?, N^N? = 2-(1H-pyrazol-5-yl)pyridinato (1a(x = 1)/1a?(x = 2)); 2-(1H-imidazol-5-yl)pyridinato (1b/1b?); 2-(1H-imidazol-2-yl)pyridinato (1c/1c?); 2-(1H-1,2,4-triazol-5-yl)pyridinato (2a/2a?); 2-(1H-1,2,3-triazol-5-yl)pyridinato (2b/2b?); 2-(4H-1,2,4-triazol-3-yl)pyridinato (2c/2c?)]. The absorption intensities and band positions are obviously affected by the variation of N substitution in N^N? ligand. The emission properties show an apparent dependence on the solvent effects, and the N^N? ligand plays an important role in governing the emissive state. The pyrazolyl-pyridyl-based N^N? ligand is considered to be more beneficial for blue OLEDs emitters.

Liu, Yuqi; Si, Yanling; Wang, Ying; Wu, Zhijian

2014-08-01

251

Nickel-catalyzed amination of aryl phosphates through cleaving aryl C-O bonds.  

Science.gov (United States)

The amination of triaryl phosphates was achieved using a Ni(II)-(?-Aryl) complex/NHC catalyst system in dioxane at 110 °C in the presence of NaH as base. Electron-neutral, -rich, and -deficient triaryl phosphates were coupled with a wider range of amine partners including cyclic and acyclic secondary amines, aliphatic primary amines, and anilines in good to excellent yields. PMID:21688805

Huang, Jin-Hua; Yang, Lian-Ming

2011-07-15

252

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

253

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

254

Docking of oxalyl aryl amino benzoic acid derivatives into PTP1B.  

Science.gov (United States)

Protein Tyrosine Phosphatases (PTPs) that function as negative regulators of the insulin signaling cascade have been identified as novel targets for the therapeutic enhancement of insulin action in insulin resistant disease states. Reducing Protein Tyrosine Phosphatase1B (PTP1B) abundance not only enhances insulin sensitivity and improves glucose metabolism but also protects against obesity induced by high fat feeding. PTP1B inhibitors such as Formylchromone derivatives, 1, 2-Naphthoquinone derivatives and Oxalyl aryl amino benzoic derivatives may eventually find an important clinical role as insulin sensitizers in the management of Type-II Diabetes and metabolic syndrome. We have carried out docking of modified oxalyl aryl amino benzoic acid derivatives into three dimensional structure of PTP1B using BioMed CAChe 6.1. These compounds exhibit good selectivity for PTP1B over most of phosphatases in selectivity panel such as SHP-2, LAR, CD45 and TCPTP found in literature. This series of compounds identified the amino acid residues such as Gly220 and Arg221 are important for achieving specificity via H-bonding interactions. Lipophilic side chain of methionine in modified oxalyl aryl amino benzoic acid derivative [1b (a2, b2, c1, d)] lies in closer vicinity of hydrophobic region of protein consisted of Meth258 and Phe52 in comparison to active ligand. Docking Score in [1b (a2, b2, c1, d)] is -131.740Kcal/mol much better than active ligand score -98.584Kcal/mol. This information can be exploited to design PTP1B specific inhibitors. PMID:19238234

Verma, Neelam; Mittal, Minakshi; Verma, Raman Kumar

2008-01-01

255

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

256

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

257

Synthesis and anti-inflammatory evaluation of some new acyl-hydrazones bearing 2-aryl-thiazole.  

Science.gov (United States)

This work describes recent results from our research program aiming at the synthesis and evaluation of new compounds acting as potential anti-inflammatory drugs. A series of novel acyl-hydrazones bearing 2-aryl-thiazole moiety were synthesized by the condensation between derivatives of 4-[2-(4-methyl-2-phenyl-thiazole-5-yl)-2-oxo-ethoxy]-benzaldehyde and 2, 3 or 4-(2-aryl-thiazol-4-ylmethoxy)-benzaldehyde, respectively and different carboxylic acid hydrazides. The structures of newly synthesized compounds were established by the combined use of IR, (1)H NMR, mass spectral data and elemental analysis. These compounds were tested in vivo for their anti-inflammatory activity, in an acute experimental inflammation. The acute phase bone marrow response, phagocytes' activity and NO synthesis were evaluated. Compounds 10, 15, 17, 18 and 22 reduced the absolute leukocytes count due to the lower neutrophils percentage. Phagocitary index was decreased by all the compounds. Seven of them reduced the phagocitary activity. Five compounds inhibited NO synthesis, 3, 4, 16 and 22 stronger than Meloxicam, the anti-inflammatory reference drug. PMID:21163557

Moldovan, Cristina Mariana; Oniga, Ovidiu; Pârvu, Alina; Tiperciuc, Brîndu?a; Verite, Philippe; Pîrn?u, Adrian; Cri?an, Ovidiu; Boji??, Marius; Pop, Raluca

2011-02-01

258

Cobalt-catalyzed aryl-sulfur bond formation.  

Science.gov (United States)

A new cobalt-catalyzed coupling of aryl halides with thiophenols and alkanethiols is reported. A variety of aryl sulfides can be prepared in excellent yields under mild reaction conditions using 1-2 mol % of CoI2(dppe) and Zn. This new cobalt-catalyzed coupling represents an interesting addition to previously known methods to synthesize thioethers. [reaction: see text]. PMID:17107085

Wong, Ying-Chieh; Jayanth, Thiruvellore Thatai; Cheng, Chien-Hong

2006-11-23

259

Photoreactivity of fluoroquinolones: nature of aryl cations generated in water  

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The nature of stabilized aryl cations generated from photodehalogenations of fluoroquinolones in aqueous media has been studied by comparing the photophysical and photochemical behavior of lomefloxacin (LFX) and its N(40)-acetylated form (ALFX). Photoproduct studies, laser flash photolysis, and emission measurements have shown that this small peripheral modification produces important changes in the properties of the singlet aryl cations generated. Also, in basic medium, a new photodehalogena...

Soldevila Serrano, Sonia; Bosca Mayans, Francisco

2012-01-01

260

High boron content carboranyl-functionalized aryl ether derivatives displaying photoluminescent properties.  

Science.gov (United States)

The reaction of alpha,alpha'-bis(3,5-bis(bromomethyl)phenoxy-p-xylene (3) with 4 equiv of the monolithium salt of 1-Ph-1,2-C2B10H11 or 1-Me-1,2-C2B10H11 gave the corresponding neutral carboranyl-functionalized aryl ether derivatives closo-4 and closo-5, respectively. These compounds contain four closo clusters that were degraded using basic conditions with KOH in EtOH, affording the corresponding nido-6 and nido-7 as potassium salts. Nido species were also isolated with tetramethylammonium as cation giving compounds nido-8 and nido-9 in good yield. The potassium salts showed good solubility in water and polar solvents. All these compounds were characterized by 1H, 11B and 13C NMR spectroscopy and UV-vis. The electronic data in different solvents indicated a solvatochromic shift for all compounds and a red shift of the absorption maxima for the nido species with respect to the closo derivatives. These neutral and anionic carboranyl-functionalized aryl ether derivatives represent a new family of high boron content luminescent compounds that show strong fluorescence emission in different solvents at room temperature. This phenomenon is very interesting considering the fact that none of the precursors have such a property. The fluorescence emission depends on the cluster substituent (Ph or Me) and the solvent polarity. Additionally, the fluorescence emission intensity was clearly dependent on the solvent polarity; the closo species showed strongest fluorescence intensities in the non-polar solvents, while anionic species were highly emissive in polar solvents. PMID:17702168

Lerouge, Frédéric; Viñas, Clara; Teixidor, Francesc; Núñez, Rosario; Abreu, Arturo; Xochitiotzi, Elba; Santillan, Rosa; Farfán, Norberto

2007-05-21

 
 
 
 
261

Synthesis and anticonvulsant activity of some potent 5,6-bis aryl 1,2,4-triazines  

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In the present research, a series of 5,6-bis aryl 1,2,4-triazines 5a~5f were synthesized by condensation of various benzils 4a~4f with aminoguanidine bicarbonate and were screened in vivo, for their anticonvulsant and neurotoxicity studies. Compounds 5a, 5b and 5d were found to be potent molecules of this series, when compared with the reference drugs phenytoin sodium, diazepam and lamotrigine. The structures of these compounds were established by IR, 1H NMR, 13C NMR and mass spectroscopic data.

Mallikarjuna, B. P.; Suresh Kumar, G. V.; Sastry, B. S.; Nagaraj; Manohara, K. P.

2007-01-01

262

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

DEFF Research Database (Denmark)

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

Kromann, Hasse; SlØk, Frank A

2002-01-01

263

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

Directory of Open Access Journals (Sweden)

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

Milton Edward J

2007-05-01

264

Directing aryl-I versus Aryl-Br bond activation by nickel via a ring walking process.  

Science.gov (United States)

Activation of a strong aryl-Br bond of a halogenated vinylarene by nickel(0) is demonstrated in the presence of aryl-I containing substrates. eta2-Coordination of Ni(PEt3)2 to the C=C moiety of halogenated vinylarenes is kinetically preferable and is followed by an intramolecular aryl-halide bond activation process. This "ring-walking" process is quantitative and proceeds under mild reaction conditions in solution. Mechanistic studies indicate that the metal insertion into the aryl-halide bond is not the rate-determining step. The reaction obeys first-order kinetics in the eta2-coordination complexes with almost identical activation parameters for Br and I derivatives. The ring-walking process is kinetically accessible as shown by density functional theory (DFT) calculations at the PBE0/SDB-cc-pVDZ//PBE0/SDD level of theory. PMID:18484721

Zenkina, Olena V; Karton, Amir; Freeman, Dalia; Shimon, Linda J W; Martin, Jan M L; van der Boom, Milko E

2008-06-16

265

Transition-metal-free C-C bond forming reactions of aryl, alkenyl and alkynylboronic acids and their derivatives.  

Science.gov (United States)

Investigation of new methods for the synthesis of C-C bonds is fundamental for the development of new organic drugs and materials. Aryl-, alkenyl- and alkynylboronic acids and their derivatives constitute attractive reagents towards this end, due to their stability, low toxicity and ease of handling. However, these compounds are only moderately nucleophilic. Consequently, the most popular C-C bond forming reactions of these boronic acids, such as the Suzuki-Miyaura, Heck, and Hayashi-Miyaura reactions, or additions to C[double bond, length as m-dash]O and C[double bond, length as m-dash]N bonds, require catalysis by transition metals. However, due to the toxicity and cost of transition metals, some new methods for C-C bond formation using aryl-, alkenyl- and alkynylboronic acids under transition-metal-free conditions are beginning to emerge. In this tutorial review, the recent synthetic advances in this field are highlighted and discussed. PMID:25181967

Roscales, S; Csákÿ, A G

2014-12-21

266

Highly selective directed arylation reactions via back-to-back dehydrogenative C-H borylation/arylation reactions.  

Science.gov (United States)

Dimeric rhodium N-heterocyclic carbene complexes are demonstrated to be effective catalyst precursors for directed C-H borylation reactions at room temperature. The reactions are highly selective for mono-borylation and can be combined with a one-pot Suzuki-Miyaura coupling to give C-H arylation products with exclusive selectivity for mono-arylation without the requirement for steric blocking groups. PMID:25025984

Keske, Eric C; Moore, Brandon D; Zenkina, Olena V; Wang, Ruiyao; Schatte, Gabriele; Crudden, Cathleen M

2014-09-01

267

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

Science.gov (United States)

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

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

2006-01-01

268

The size of the aryl linker between two polyaza-cyclophane moieties controls the binding selectivity to ds-RNA vs. ds-DNA.  

Science.gov (United States)

Aryl-linked (pyridine- vs. phenanthroline-) bis-polyaza pyridinophane scorpiands PYPOD and PHENPOD strongly bind to the double stranded DNA and RNA, whereby very intriguing RNA over DNA selectivity is finely tuned by aryl-linker length and aromatic surface. Moreover, PYPOD and PHENPOD dimer formation at high compound/polynucleotide ratios is highly sensitive to the fine interplay between the steric and binding properties of compound-dimers and the DNA minor groove/RNA major groove. That is demonstrated by significantly different induced CD spectra, which allow spectroscopic differentiation between various DNA/RNA secondary structures. A significantly higher (micromolar) antiproliferative effect of PYPOD and PHENPOD on human cell lines with respect to previously reported pyridine-based tripodal aliphatic polyamines is attributed to masked positive charges and increased hydrophobicity of novel compounds, resulting in more efficient membrane permeation and cellular uptake. PMID:23392228

González-García, Jorge; Uzelac, Lidija; Kralj, Marijeta; Llinares, José M; García-España, Enrique; Piantanida, Ivo

2013-04-01

269

Synthesis of aryl-1H-1,2,3-triazoles via 1,3-dipolar cycloaddition  

Directory of Open Access Journals (Sweden)

Full Text Available A series of Aryl-1H-1,2,3-triazoles were prepared from the reaction between aril-azide (1 with 1.5 equiv. of terminal alkynes (2a-o. The reactions carried out at room temperature and in the presence of CuI (10 mol% in acetonitrile. The compounds (3a-o were obtained in moderate-to-good yields (50-94%. In general, not was observed significant inductive effect on the reactivity of the alkynes (2a-f. The alcohol alkynes (2i-k showed moderate yields 50-72%. On the other hand, the reaction with alkyl alkynes (2m,n furnished the compounds (3m and (3n in excellent yields of 89% and 90%, respectively.

Wagner O. Valença

2012-06-01

270

Discovery and evaluation of potent P1 aryl heterocycle-based thrombin inhibitors.  

Science.gov (United States)

In an effort to discover potent, clinically useful thrombin inhibitors, a rapid analogue synthetic approach was used to explore the P(1) region. Various benzylamines were coupled to a pyridine/pyrazinone P(2)-P(3) template. One compound with an o-thiadiazole benzylic substitution was found to have a thrombin K(i) of 0.84 nM. A study of ortho-substituted five-membered-ring heterocycles was undertaken and subsequently demonstrated that the o-triazole and tetrazole rings were optimal. Combination of these potent P(1) aryl heterocycles with a variety of P(2)-P(3) groups produced a compound with an extraordinary thrombin inhibitory activity of 1.4 pM. It is hoped that this potency enhancement in P(1) will allow for more diversification in the P(2)-P(3) region to ultimately address additional pharmacological concerns. PMID:15163182

Young, Mary Beth; Barrow, James C; Glass, Kristen L; Lundell, George F; Newton, Christina L; Pellicore, Janetta M; Rittle, Kenneth E; Selnick, Harold G; Stauffer, Kenneth J; Vacca, Joseph P; Williams, Peter D; Bohn, Dennis; Clayton, Franklin C; Cook, Jacquelynn J; Krueger, Julie A; Kuo, Lawrence C; Lewis, S Dale; Lucas, Bobby J; McMasters, Daniel R; Miller-Stein, Cynthia; Pietrak, Beth L; Wallace, Audrey A; White, Rebecca B; Wong, Bradley; Yan, Youwei; Nantermet, Philippe G

2004-06-01

271

Reductive carbonylation of aryl halides employing a two-chamber reactor: a protocol for the synthesis of aryl aldehydes including 13C- and D-isotope labeling.  

Science.gov (United States)

A protocol has been developed for conducting the palladium-catalyzed reductive carbonylation of aryl iodides and bromides using 9-methylfluorene-9-carbonyl chloride (COgen) as a source of externally delivered carbon monoxide in a sealed two-chamber system (COware), and potassium formate as the in situ hydride source. The method is tolerant to a wide number of functional groups positioned on the aromatic ring, and it can be exploited for the isotope labeling of the aldehyde group. Hence, reductive carbonylations run with (13)COgen provide a facile access to (13)C-labeled aromatic aldehydes, whereas with DCO2K, the aldehyde is specifically labeled with deuterium. Two examples of double isotopic labeling are also demonstrated. Finally, the method was applied to the specific carbon-13 labeling of the ?-amyloid binding compound, florbetaben. PMID:23692554

Korsager, Signe; Taaning, Rolf H; Lindhardt, Anders T; Skrydstrup, Troels

2013-06-21

272

Microwave-mediated and customery synthesis of N-benzoyl- or N-substituted benzoyl-N,N'-dialkylureas from arylcarboxylic acids and N,N'-disubstituted carbodiimides under solvent-free conditions  

International Nuclear Information System (INIS)

An easy, efficient and quick synthesis of N-benzoyl-(and N-substituted benzoyl)-N,N'dialkylureas, in good yields, under solvent-free conditions is described. First, the reaction between a carboxylic acid and a disubstituted carbodiimide was carried out employing microwave radiation, and later on the same reaction was performed separately under dry heating without any radiation. The yields are comparable in both cases. (author)

273

Rational design, green synthesis, and initial evaluation of a series of full-color tunable fluorescent dyes enabled by the copper-catalyzed N-arylation of 6-phenyl pyridazinones and their application in cell imaging.  

Science.gov (United States)

There is widespread interest in the application, optimization, and evolution of the transition-metal-catalyzed arylation of N-heteroarenes to discover full-color tunable fluorescent core frameworks. Inspired by the versatile roles of pyridazinone in organic synthesis and medicinal chemistry, herein, we report a simple and efficient copper-catalyzed cross-coupling reaction for the N-functionalization of pyridazinones in neat water. To achieve the efficient conversion of pyridazinones and organic halides in aqueous phase, a series of copper-salen complexes composed of different Schiff base ligands were investigated by rational design. A final choice of fine-tuned hydrophilicity balanced with lipophilicity among the candidates was confirmed, which affords excellent activity towards the reaction of a wide range of pyridazinones and organic halides. More importantly, the products as N-substituted pyridazinones were synthesized rationally by this methodology as full-color tunable fluorescent agents (426-612?nm). The N2 position of pyridazinones was modified by different aryl group such as benzothiazole, N,N-dimethylaniline, 3-quinoline, 4-isoquinoline and 2-thiophene, resulting in a series of full-color tunable fluorescent reagents. Meanwhile, the effects of electron-donating and electron-withdrawing groups of the 6-substituted phenyl ring have also been investigated to optimize the fluorescent properties. These fluorescent core frameworks were studied in several cell lines as fluorescent dyes. Different colors from blue to red were observed by using fluorescence microscopy and confocal microscopy. PMID:24038329

Liang, Lei; Wang, Wei; Wu, Jun; Xu, Fengrong; Niu, Yan; Xu, Bo; Xu, Ping

2013-10-01

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 (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.

Mehmet Emin Topaloglu

2011-06-01

275

Transition-metal-catalyzed direct arylations via C–H bond cleavages  

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Abstract: Palladium catalysts allowed for intermolecular direct arylations of heteroarenes with aryl chlorides, tosylates, or mesylates as electrophiles. As an economically attractive alter-native, inexpensive copper catalysts could be employed for regioselective C–H bond aryl-ations of 1,2,3-triazoles. On the contrary, intermolecular C–H bond functionalizations of arenes were accomplished with ruthenium complexes derived from air-stable (heteroatom-substituted) secondary phosphine oxide...

Ackermann, Lutz

2010-01-01

276

Tuning Aryl?CH···O 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?CH···O bonding in forming self-assembled low-nuclearity structures at room temperature and to compare aryl?CH···O 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?CH···O 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?CH···O 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

277

Synthesis of novel 5-(3-alkylquinolin-2-yl)-3-aryl isoxazole derivatives and their cytotoxic activity.  

Science.gov (United States)

The propargyl alcohol on reaction with aldoxime and NaOCl in DCM gave exclusively (3-arylisoxazol-5-yl) methanol 1. The compound 1 was oxidized to an aldehyde 2 followed by reaction with aniline resulted in Schiff's base 3. The compounds 3 were further reacted with various aldehydes having ?-hydrogen using molecular iodine as catalyst and which yielded 5-(3-alkylquinolin-2-yl)-3-aryl isoxazole derivatives 4. All the final compounds 4 were screened against four human cancer cell lines (A549, COLO 205, MDA-MB 231 and PC-3) and among these compounds 4n showed potent cytotoxicity against all the cell lines at IC50 values of <12 ?M. PMID:24507927

Sambasiva Rao, P; Kurumurthy, C; Veeraswamy, B; Poornachandra, Y; Ganesh Kumar, C; Narsaiah, B

2014-03-01

278

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

Science.gov (United States)

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

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

2013-07-01

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

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

 
 
 
 
281

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

282

Design and synthesis of N-alkyl-N'-substituted 2,4-dioxo-3,4-dihydropyrimidin-1-diacylhydrazine derivatives as ecdysone receptor agonist.  

Science.gov (United States)

Based on the discovery of thymine as an ecdysteroid agonist, a series of 1,4-disubstituted diacylhydrazine derivatives with a thymine moiety were designed and synthesized. The activities of these compounds against Spodoptera litura (Fabricius) were evaluated by the insect immersion method. Results showed that compound 2h with an N-cyclohexylmethyl substituent exhibits the most potent agonist activity with a median lethal concentration of 23.21 ?g/mL. This compound also caused malformation of molting larvae and adults. Compound 2 h was further demonstrated as an ecdysteroid agonist by reporter gene assay on the Spodoptera frugiperda cell line (Sf9 cells). A molecular docking study indicated that hydrophobic interactions and the formation of hydrogen bonds between the compounds and the ecdysone receptor play critical roles in promoting the binding affinity of the compound. The structure of compound 2h may serve as a favorable template for the development of new ecdysteroid agonists with a pyrimidinedione moiety. PMID:23757207

Liu, Xiu; Zhang, Ling; Tan, Jin-Guo; Xu, Han-Hong

2013-08-01

283

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

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

ASIF HUSAIN

2008-08-01

284

Functionalization of heterocyclic compounds using polyfunctional magnesium and zinc reagents  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2011-01-01

285

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

286

Design, Synthesis and Antiviral Potential of 14-Aryl/Heteroaryl-14H-dibenzo[a,j]xanthenes Using an Efficient Polymer-Supported Catalyst  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Polyethyleneglycol bound sulfonic acid (PEG-OSO3H), a chlorosulphonic acid-modified polyethylene glycol was successfully used as an efficient and eco-friendly polymeric catalyst in the synthesis of 14-aryl/heteroaryl-14H-dibenzo[a,j]xanthenes obtained from the reaction of 2-naphthol and carbonyl compounds under solvent-free conditions with short reaction times and excellent yields. The biological properties of these synthesized ...

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

2012-01-01

287

Synthesis of Sulfur-Containing Aryl and Heteroaryl Vinyls via Suzuki–Miyaura Cross-Coupling for the Preparation of SERS-Active Polymers  

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The preparation of sulfur-containing aryl and heteroaryl vinyl co-monomers via Suzuki–Miyaura cross-coupling between the corresponding mercaptomethyl arylboronates and in situ-generated vinyl bromides is described. Surface enhanced Raman scattering (SERS) studies of the target compounds on gold nanoparticles confirmed their potential as spectroscopic tags in the fabrication of SERS–encoded polymers for combinatorial screening and biomedical diagnostics.

Perez-pineiro, Rolando; Dai, Sheng; Alvarez-puebla, Ramon; Wigginton, James; Al-hourani, Baker Jawabrah; Fenniri, Hicham

2009-01-01

288

Anomalous reactivity of silylborane: transition-metal-free boryl substitution of aryl, alkenyl, and alkyl halides with silylborane/alkoxy base systems.  

Science.gov (United States)

An unexpected borylation of organic halides with a silyborane in the presence of an alkoxy base has been observed. This formal nucleophilic boryl substitution can be applied to a broad range of substrates with high functional group compatibility. Even sterically hindered aryl bromides afforded the corresponding boryl compounds in high yields. Preliminary mechanistic studies indicated that this boryl substitution is promoted by neither transition-metal contamination nor a radical-mediated process. PMID:23171366

Yamamoto, Eiji; Izumi, Kiyotaka; Horita, Yuko; Ito, Hajime

2012-12-12

289

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

290

Stereocontrolled synthesis of contiguous C(sp3)-C(aryl) bonds by lanthanide(III)-catalyzed domino aryl-Claisen [3,3]-sigmatropic rearrangements.  

Science.gov (United States)

A domino [3,3]-sigmatropic aryl-Claisen rearrangement of cyclic and acyclic bisaryloxy-substituted alkenes can be performed in high yield by using Ln(fod)(3) catalysis to obtain bisphenolic products incorporating two contiguous aryl-C(sp(3)) bonds. Stereospecific rearrangement was observed for cyclic substrates. The precursor diaryl ethers were typically synthesized from the corresponding diols by double arylation procedures using either copper catalyzed coupling of aryltrifluoroborate salts or by S(N)Ar reaction. PMID:20857953

Ramadhar, Timothy R; Kawakami, Jun-ichi; Lough, Alan J; Batey, Robert A

2010-10-15

291

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, Jörg; Hassiepen, Ulrich; Duttaroy, Alokesh; Ferreira, Suzie; Sutton, Jon M; Clark, David E; Fenton, Garry; Beswick, Mandy; Baeschlin, Daniel K

2014-02-01

292

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

293

An Efficient Three Component One-Pot Synthesis of 5-Amino-7-aryl-7,8-dihydro-[1,2,4] triazolo[4,3-a]-pyrimidine-6-carbonitriles  

Directory of Open Access Journals (Sweden)

Full Text Available A series of novel 5-amino-7-aryl-7,8-dihydro-[1,2,4] triazolo[4,3-a]-pyrimidine-6-carbonitriles were synthesized by a one-pot reaction of 3-amino-1,2,4-triazole, malononitrile and aryl aldehydes in the presence of 20 mol% NaOH in ethanol under heating or ultrasonic irradiation. The structures of the target compounds were confirmed by inspection of their 1H- NMR, 13C-NMR, IR and MS spectra. The advantages of this method are short reaction times, good yields, high selectivity and operational simplicity.

Sun Wan-Fu

2012-02-01

294

Aryl-1,3,5-triazine derivatives as histamine H4 receptor ligands.  

Science.gov (United States)

A series of novel 2-amino-4-(4-methylpiperazin-1-yl)-1,3,5-triazine derivatives with different aryl substituents in the 6-position was designed, synthesized and evaluated for histamine H4 receptor (H4R) affinity in Sf9 cells expressing human H4R co-expressed with G-protein subunits. Triazine derivative 8 with a 6-(p-chlorophenyl) substituent showed the highest affinity with hH4R Ki value of 203 nM and was classified as an antagonist in cAMP accumulation assay. This compound, identified as a new lead structure, demonstrated also anti-inflammatory properties in preliminary studies in mice (carrageenan-induced edema test) and neither possessed significant antiproliferative activity, nor modulated CYP3A4 activity up to concentration of 25 ?M. In order to discuss structure-activity relationships molecular modeling and docking studies were undertaken. PMID:24996140

?a?ewska, Dorota; Wi?cek, Ma?gorzata; Ner, Joanna; Kami?ska, Katarzyna; Kottke, Tim; Schwed, J Stephan; Zygmunt, Ma?gorzata; Karcz, Tadeusz; Olejarz, Agnieszka; Kuder, Kamil; Latacz, Gniewomir; Grosicki, Marek; Sapa, Jacek; Karolak-Wojciechowska, Janina; Stark, Holger; Kie?-Kononowicz, Katarzyna

2014-08-18

295

Structure and cytotoxicity of arnamial and related fungal sesquiterpene aryl esters.  

Science.gov (United States)

We report on the structure elucidation of arnamial, a new Delta(2,4)-protoilludane everninate ester from the fungus Armillaria mellea, and on the apoptotic activity of arnamial as well as the cytotoxic activity of structurally related compounds on selected human cancer cells. Arnamial showed cytotoxicity against Jurkat T cells, MCF-7 breast adenocarcinoma, CCRF-CEM lymphoblastic leukemia, and HCT-116 colorectal carcinoma cells at IC50 = 3.9, 15.4, 8.9, and 10.7 microM, respectively, and the related aryl ester melledonal C showed cytotoxic activity against CCRF-CEM cells (IC50 = 14.75 microM). [1,2-13C2]Acetate feeding supports a polyketide origin of the orsellinic acid moiety of arnamial. PMID:19795841

Misiek, Mathias; Williams, Jessica; Schmich, Kathrin; Hüttel, Wolfgang; Merfort, Irmgard; Salomon, Christine E; Aldrich, Courtney C; Hoffmeister, Dirk

2009-10-01

296

Strong intermolecular exciton couplings in solid-state circular dichroism of aryl benzyl sulfoxides.  

Science.gov (United States)

A series of 13 enantiopure aryl benzyl sulfoxides () with different substituents on the two aromatic rings has been previously analyzed by means of electronic circular dichroism (CD) spectroscopy. Most of these compounds are crystalline and their X-ray structure is established. For almost one-half of the series, CD spectra measured in the solid state were quite different from those in acetonitrile solution. We demonstrate that the difference is due to strong exciton couplings between molecules packed closely together in the crystal. The computational approach consists of time-dependent density functional theory (TDDFT) calculations run on "dimers" composed of nearest neighbors found in the lattice. Solid-state CD spectra are well reproduced by the average of all possible pairwise terms. The relation between the crystal space group and conformation, and the appearance of solid-state CD spectra, is also discussed. PMID:24327405

Padula, Daniele; Pietro, Sebastiano Di; Annunziata, Maria; Capozzi, M; Cardellicchio, Cosimo; Pescitelli, Gennaro

2014-09-01

297

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)

298

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

299

Studies on 1,2,4-triazole derivatives as potential anti-inflammatory agents.  

Science.gov (United States)

The reaction of acetic or propionic acid hydrazides with various aryl/alkyl isothiocyanates gave thiosemicarbazides which furnished the 1,2,4-triazoles by alkali cyclization. The 4-aryl/alkyl-5-(1-phenoxyethyl)-3-[N-(substituted)acetamido]thio-4H-1,2,4-triazole derivatives were synthesized by reacting the triazoles with 2-chloro-N-(substituted)acetamide. The chemical structures of the compounds were elucidated by IR, (1)H-NMR, FAB(+)-MS spectral data and elemental analysis. In the pharmacological studies, anti-inflammatory activities of these compounds have been screened and significant activities were observed. PMID:17994651

Turan-Zitouni, Gülhan; Kaplancikli, Zafer Asim; Ozdemir, Ahmet; Chevallet, Pierre; Kandilci, Hilmi Burak; Gümüsel, Bülent

2007-11-01

300

A FACILE ONE-POT SYNTHESIS OF NOVEL 1,1?-(ALKANEDIYLBIS(5-OXO-3- ALKYL/ARALKYL/ARYL-1,2,3,4,5,6,7,8-OCTAHYDROQUINAZOLINES and THEIR ANTI-BACTERIAL ACTIVITIES A FACILE ONE-POT Synthese von neuartigen 1,1 '- (Alkandiyl BIS (5-oxo-3- ALKYL/ARALKYL/ARYL-1,2,3,4,5,6,7,8-OCTAHYDROQUINAZOLINES and their Anti-bakterielle AKTIVITÄTEN  

Directory of Open Access Journals (Sweden)

Full Text Available A facile one-pot synthesis of novel 1,1?-(alkanediylbis(5-oxo-3-alkyl/aralkyl/aryl- 1,2,3,4,5,6,7,8-octahydroquinazolines 3a-r has been devised by the cyclocondensation of bisenaminones 2a-f with primary amine and formaldehyde. The structures of the products have been established by spectral and analytical data as 1, 1?-(alkanediylbis(5-oxo-3-alkyl/ aralkyl/aryl-1,2,3,4,5,6,7,8-octahydroquinazolines. Some of the compounds have been found to possess promising anti-bacterial properties.

Madhusudhan Saha and Jai N. Vishwakarma

2013-04-01

 
 
 
 
301

Characterization of Natural Aryl Hydrocarbon Receptor Agonists from Cassia Seed and Rosemary  

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Full Text Available Many recent studies have suggested that activation of the aryl hydrocarbon receptor (AhR reduces immune responses, thus suppressing allergies and autoimmune diseases. In our continuing study on natural AhR agonists in foods, we examined the influence of 37 health food materials on the AhR using a reporter gene assay, and found that aqueous ethanol extracts of cassia seed and rosemary had particularly high AhR activity. To characterize the AhR-activating substances in these samples, the chemical constituents of the respective extracts were identified. From an active ethyl acetate fraction of the cassia seed extract, eight aromatic compounds were isolated. Among these compounds, aurantio-obtusin, an anthraquinone, elicited marked AhR activation. Chromatographic separation of an active ethyl acetate fraction of the rosemary extract gave nine compounds. Among these compounds, cirsimaritin induced AhR activity at 10–102 ?M, and nepitrin and homoplantagenin, which are flavone glucosides, showed marked AhR activation at 10–103 ?M.

Yoshiaki Amakura

2014-04-01

302

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

Science.gov (United States)

Many recent studies have suggested that activation of the aryl hydrocarbon receptor (AhR) reduces immune responses, thus suppressing allergies and autoimmune diseases. In our continuing study on natural AhR agonists in foods, we examined the influence of 37 health food materials on the AhR using a reporter gene assay, and found that aqueous ethanol extracts of cassia seed and rosemary had particularly high AhR activity. To characterize the AhR-activating substances in these samples, the chemical constituents of the respective extracts were identified. From an active ethyl acetate fraction of the cassia seed extract, eight aromatic compounds were isolated. Among these compounds, aurantio-obtusin, an anthraquinone, elicited marked AhR activation. Chromatographic separation of an active ethyl acetate fraction of the rosemary extract gave nine compounds. Among these compounds, cirsimaritin induced AhR activity at 10-10² ?M, and nepitrin and homoplantagenin, which are flavone glucosides, showed marked AhR activation at 10-10³ ?M. PMID:24747651

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

2014-01-01

303

Photochemical Aryl Radical Cyclizations to Give (E-3-Ylideneoxindoles  

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Full Text Available (E-3-Ylideneoxindoles are prepared in methanol in reasonable to good yields, as adducts of photochemical 5-exo-trig of aryl radicals, in contrast to previously reported analogous radical cyclizations initiated by tris(trimethylsilylsilane and azo-initiators that gave reduced oxindole adducts.

Michael Gurry

2014-09-01

304

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

305

Photochemical aryl radical cyclizations to give (E)-3-ylideneoxindoles.  

Science.gov (United States)

(E)-3-Ylideneoxindoles are prepared in methanol in reasonable to good yields, as adducts of photochemical 5-exo-trig of aryl radicals, in contrast to previously reported analogous radical cyclizations initiated by tris(trimethylsilyl)silane and azo-initiators that gave reduced oxindole adducts. PMID:25271428

Gurry, Michael; Allart-Simon, Ingrid; McArdle, Patrick; Gérard, Stéphane; Sapi, Janos; Aldabbagh, Fawaz

2014-01-01

306

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, ¹H 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

307

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)

308

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, ¹H 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.

309

Synthesis and antitubercular activities of substituted benzoic acid N'-(substituted benzylidene/furan-2-ylmethylene)-N-(pyridine-3-carbonyl)-hydrazides.  

Science.gov (United States)

A series of benzoic acid hydrazones and its nicotinyl derivatives (1-10) were prepared and evaluated for their antitubercular activity towards a strain of Mycobacterium tuberculosis (MTB). The structures of newly synthesized compounds were confirmed by infrared (IR) and 1H-nuclear magnetic resonance (NMR) spectral data and elemental analysis. The in vitro antitubercular activity of synthesized compounds against MTB was carried out in Middlebrook 7H11agar medium supplemented with OADC by agar dilution method. The antitubercular activity results indicated that nicotinic acid N-(3,5-dinitro-benzoyl)-N'-(4-methoxy-benzylidene)-hydrazide (1) is the most potent among the synthesized compounds with MIC of 3.5×10(-3) ?M. PMID:20828886

Kumar, Pradeep; Narasimhan, Balasubramanian; Yogeeswari, Perumal; Sriram, Dharmarajan

2010-12-01

310

Discovery of novel lead in the group of N-substituted piperazine ether derivatives with potential histamine H3 receptor activity.  

Science.gov (United States)

The search for novel lead from the group of various substituted N-piperazine ether derivatives was performed. Acyl- and pyridylpiperazine ethyl/propyl ethers were obtained via three different synthetic pathways. Affinity to histamine H3 receptor was established, as well as, for selected compounds, selectivity towards histamine H4R. Docking studies to the histamine H3R homology model strengthened the position of (4-(3-(4-(3-chlorobenzoyl)piperazin-1- yl)propoxy)phenyl)(cyclopropyl)methanone (compound 26) as a novel lead for further studies on histamine H3 receptor antagonist/inverse agonist. PMID:24047214

Kuder, Kamil J; Stachnik, Marta; Schunack, Walter; Szyma?ska, Ewa; Kie?-Kononowicz, Katarzyna

2014-01-01

311

Synthesis and biological evaluation of novel substituted 1,3,4-thiadiazole and 2,6-di aryl substituted imidazo [2,1-b] [1,3,4] thiadiazole derivatives.  

Science.gov (United States)

A new series of N-[5-(4-(alkyl/aryl)-3-nitro-phenyl)-[1,3,4-thiadiazol-2-yl]-2,2-dimethyl-propionamide 4 (a-l) and 6-(4-Methoxy-phenyl)-2-(4-alkyl/aryl)-3-nitro-phenyl)-Imidazo [2,1-b] [1,3,4] thiadiazole 6 (a-l) were synthesized starting from 5-(4-Fluoro-3-nitro-phenyl)-[1,3,4] thiadiazole-2-ylamine. The synthesized compounds were characterized by IR, NMR, mass spectral and elemental analysis. All the compounds were tested for antibacterial and antifungal activities. The antimicrobial activities of the compounds were assessed by well plate method (zone of inhibition). Compounds 4a, 4c and 6e, 6g displayed appreciable activity at the concentration 0.5-1.0 mg/mL. PMID:24321835

Chandrakantha, B; Isloor, Arun M; Shetty, Prakash; Fun, Hoong Kun; Hegde, Gurumurthy

2014-01-01

312

Synthesis of N-aryl-5-amino-4-cyanopyrazole derivatives as potent xanthine oxidase inhibitors.  

Science.gov (United States)

Some pyrazolo[3,4-d]pyrimidines, structurally related with allopurinol, a well known xanthine oxidase inhibitor, clinically used in the therapy of gout, have also been reported as potent inhibitors of xanthine oxidase and the growth of several human tumour cell lines. Considering the potential interest of this family of compounds, the aim of the present study was to synthesise and provide a full chemical characterization of new N-aryl-5-amino-4-cyanopyrazole derivatives and their corresponding pyrazolo[3,4-d]pyrimidines. Their biological activity pertaining to the xanthine oxidase inhibition and effect on the growth of three tumour cell lines (MCF-7, NCI-H460, and SF-268) are also provided. With only one exception, the synthesised compounds showed no effect on the growth of the three tumour cell lines. However, a strong xanthine oxidase inhibitory activity was observed for almost all pyrazolo[3,4-d]pyrimidines tested, revealing some of them IC(50) values below 1 microM. The results of the molecular docking studies of these compounds, against xanthine oxidoreductase are also described, providing an atomistic explanation of the differences in the inhibitory efficiency. MEP calculations were used to explain different inhibitory efficiency of similar inhibitors. PMID:17692432

Gupta, Sanjay; Rodrigues, Lígia M; Esteves, Ana P; Oliveira-Campos, Ana M F; Nascimento, M São José; Nazareth, N; Cidade, Honorina; Neves, Marta P; Fernandes, Eduarda; Pinto, Madalena; Cerqueira, Nuno M F S A; Brás, Natércia

2008-04-01

313

2-Aryl substituted pyridine C-region analogues of 2-(3-fluoro-4-methylsulfonylaminophenyl)propanamides as highly potent TRPV1 antagonists.  

Science.gov (United States)

A series of 2-aryl pyridine C-region derivatives of 2-(3-fluoro-4-methylsulfonylaminophenyl)propanamides were investigated as hTRPV1 antagonists. Multiple compounds showed highly potent TRPV1 antagonism toward capsaicin comparable to previous lead 7. Among them, compound 9 demonstrated anti-allodynia in a mouse neuropathic pain model and blocked capsaicin-induced hypothermia in a dose-dependent manner. Docking analysis of 9 with our hTRPV1 homology model provided insight into its specific binding mode. PMID:25011915

Ryu, HyungChul; Seo, Sejin; Kim, Myeong Seop; Kim, Mi-Yeon; Kim, Ho Shin; Ann, Jihyae; Tran, Phuong-Thao; Hoang, Van-Hai; Byun, Jieun; Cui, Minghua; Son, Karam; Sharma, Pankaz Kumar; Choi, Sun; Blumberg, Peter M; Frank-Foltyn, Robert; Bahrenberg, Gregor; Koegel, Babette-Yvonne; Christoph, Thomas; Frormann, Sven; Lee, Jeewoo

2014-08-15

314

Synthesis and pharmacological evaluation of novel N-aryl-3,4-dihydro-1'H-spiro[chromene-2,4'-piperidine]-1'-carboxamides as TRPM8 antagonists.  

Science.gov (United States)

A novel series of N-aryl-3,4-dihydro-1'H-spiro[chromene-2,4'-piperidine]-1'-carboxamides was identified as transient receptor potential melastatin 8 (TRPM8) channel blockers through analogue-based rational design, synthesis and screening. Details of the synthesis, effect of aryl groups and their substituents on in-vitro potency were studied. The effects of selected functional groups on the 4-position of the chromene ring were also studied, which showed interesting results. The 4-hydroxy derivatives showed excellent potency and selectivity. Optical resolution and screening of alcohols revealed that (R)-(-)-isomers were in general more potent than the corresponding (S)-(+)-isomers. The isomer (R)-(-)-10e (IC50: 8.9nM) showed a good pharmacokinetic profile upon oral dosing at 10mg/kg in Sprague-Dawley (SD) rats. The compound (R)-(-)-10e also showed excellent efficacy in relevant rodent models of neuropathic pain. PMID:24055075

Chaudhari, Sachin S; Kadam, Ashok B; Khairatkar-Joshi, Neelima; Mukhopadhyay, Indranil; Karnik, Pallavi V; Raghuram, Anupindi; Rao, Shobha S; Vaiyapuri, Thamil Selvan; Wale, Dinesh P; Bhosale, Vikram M; Gudi, Girish S; Sangana, Ramchandra R; Thomas, Abraham

2013-11-01

315

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

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Full Text Available A series of 2-amino-5-aryl-5H-thiazolo[4,3-b]-l,3,4-thiadiazoles were synthesized by using aromatic aldehydes, thioglycolic acid and thiosemicarbazide. Equimolar mixtures of aromatic aldehydes with thioglycolic acid and thiosemicarbazide in H2SO4 transform into 2-amino-5-aryl-5H-thiazolo[4,3-b]-l,3,4-thiadiazoles. Structures of all synthesized compounds were confirmed by FTIR, 1H NMR and mass spectral data. Fungicidal activity against two fungi Aspergillus niger and Candida albicans and bactericidal activity against two gram +ve bacteria Staphylococcus aureus, Escherichia fecalis and two gram –ve bacteria Escheridhia coli, Klebsiella pneumonia and found to be active against these microorganisms.

Karigar Asif A.

2011-02-01

316

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

Science.gov (United States)

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

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

2014-01-01

317

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

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Mechanistic studies of the hydrogenolysis of aryl ethers by nickel were undertaken with (diphosphine)aryl methyl ethers. A Ni(0) complex containing Ni-arene interactions adjacent to the aryl-O bond was isolated. Heating led to aryl-O bond activation and generation of a nickel-aryl-methoxide complex. Formal ?-H elimination from this species produced a nickel-aryl-hydride which can undergo reductive elimination in the presence of formaldehyde to generate a carbon monoxide adduct of Ni(0). The ...

Kelley, Paul; Lin, Sibo; Edouard, Guy; Day, Michael W.; Agapie, Theodor

2012-01-01

318

Dual visible light photoredox and gold-catalyzed arylative ring expansion.  

Science.gov (United States)

A combination of visible light photocatalysis and gold catalysis is applied to a ring expansion-oxidative arylation reaction. The reaction provides an entry into functionalized cyclic ketones from the coupling reaction of alkenyl and allenyl cycloalkanols with aryl diazonium salts. A mechanism involving generation of an electrophilic gold(III)-aryl intermediate is proposed on the basis of mechanistic studies, including time-resolved FT-IR spectroscopy. PMID:24730447

Shu, Xing-zhong; Zhang, Miao; He, Ying; Frei, Heinz; Toste, F Dean

2014-04-23

319

Nickel-catalyzed cross-coupling of aryl phosphates with arylboronic acids.  

Science.gov (United States)

The Suzuki-Miyaura cross-coupling of aryl phosphates using Ni(PCy(3))(2)Cl(2) as an inexpensive, bench-stable catalyst is described. Broad substrate scope and high efficiency are demonstrated by the syntheses of more than 40 biaryls and by constructing complex organic molecules. The poor reactivity of aryl phosphates relative to aryl halides is successfully employed to construct polyarenes by selective cross-coupling using Pd and Ni catalysts. PMID:21388215

Chen, Hu; Huang, Zhongbin; Hu, Xiaoming; Tang, Guo; Xu, Pengxiang; Zhao, Yufen; Cheng, Chien-Hong

2011-04-01

320

Bone Resorption Inhibition Quantitative Structure-Activity Relationships for Aryl-Substituted Bisphosphonates  

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Full Text Available Quantitative structure-activity relationships (QSAR models for the bone resorption inhibition of 29 aryl-substituted bisphosphonates (ABP were established with the CODESSA program. The QSAR models for the ABP bone resorption inhibition are obtained by selecting descriptors from a wide diversity of constitutional, topological, electrostatic and quantum structural indices. Standard quantum chemistry packages are used for optimizing the molecular geometry and for semi-empirical quantum computations at the AM1 level. A heuristic algorithm selects the best multiple linear regression equation according to the highest statistical indices; the predictive power of each QSAR model is estimated with the leave-one-out (LOO cross-validation method. For the whole set of 29 compounds, the best QSAR model (r2 = 0.8328, r2LOO = 0.7479, s2 = 0.251, F = 29.88 is obtained with four quantum descriptors (minimum total interaction for a C-P bond, maximum valency of a N atom, minimum total interaction for a C-C bond, and hydrogen-acceptors surface area. A significant improvement of the statistical indices is obtained by deleting three outliers, when a fairly good QSAR is obtained (r2 = 0.8827, r2LOO = 0.8231, s2 = 0.118, F = 39.51 also with four quantum descriptors (minimum electron-electron repulsion for a H-N bond, minimum coulombic interaction for a C-P bond, maximum one-electron reactivity index for a N atom, and minimum total interaction for a H-O bond. These results demonstrate the ability of AM1 quantum indices in modeling the bone resorption inhibition of aryl-substituted bisphosphonates.

Teodora Ivanciuc

2003-06-01

 
 
 
 
321

Arylation of sulfhydryl groups in vitro by the naturally occurring sesquiterpenoid benzoquinone avarone.  

Science.gov (United States)

Avarone (AQ) is a naturally occurring sesquiterpenoid benzoquinone possessing antileukaemic activity. Its reactivity towards glutathione (GSH) and protein sulfhydryl (SH) groups was investigated. The stoichiometry of AQ reaction with GSH at [GSH]/[AQ] ratios lower than unity proved to be 1:2 (thiol:quinone), consistent with the formation of the corresponding hydroquinone (avarol) as well as a quinone-thioether in the reaction. Conversely, when the [GSH]/[AG] ratio was higher than unity, a hydroquinone-thioether was the only reaction product. AQ/protein interaction was also investigated by using bovine serum albumin (BSA) as model compound. As observed with GSH, arylation rather than oxidation of SH groups appeared to be the mechanism responsible for the AQ-induced depletion of protein SH groups. However, AQ proved to be less effective in depleting BSA sulfhydryls than that of GSH. AQ disappearance after BSA addition was greater than expected on the basis of the total SH groups depleted, if a stoichiometric ratio 1:2 (thiol:quinone) was assumed. It also occurred in the presence of BSA with blocked SH groups, thus suggesting that AQ may react with other nucleophilic protein residues, such as amino or imino groups. When HepG2 cells were exposed to AQ, depletion of both protein SH groups and GSH occurred. However, in contrast to the above, AQ proved to be more effective, probably because of its lipophilic nature, in depleting protein SH groups than GSH. Also, in intact cells AQ appeared to arylate both SH and other nucleophilic groups in proteins. This mechanism may play a major role in AQ-induced cytotoxicity. PMID:8134925

Belisario, M A; Pecce, R; Maturo, M; De Rosa, S

1994-01-26

322

Photoredox Activation for the Direct ?-Arylation of Ketones and Aldehydes  

Science.gov (United States)

The direct ?-activation of saturated aldehydes and ketones has long been an elusive transformation. We found that photoredox catalysis in combination with organocatalysis can lead to the transient generation of 5?-electron ?-enaminyl radicals from ketones and aldehydes that rapidly couple with cyano-substituted aryl rings at the carbonyl ?-position. This mode of activation is suitable for a broad range of carbonyl ?-functionalization reactions and is amenable to enantioselective catalysis. PMID:23539600

Pirnot, Michael T.; Rankic, Danica A.; Martin, David B. C.; MacMillan, David W. C.

2013-01-01

323

Synthesis of 3-Aryl Coumarin Derivatives Using Ultrasound  

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Coumarins occupy an important place in the realm of natural products and synthetic organic chemistry. A fast and highly efficient green method for synthesizing 3-aryl coumarin derivatives from salicylaldehyde and phenyl acetyl chloride in the presence of tetrahydrofuran and K2CO3 using ultrasound irradiation is reported. Ultrasound assisted reactions have resulted in better yields and faster reaction time of the desired products than when pre...

Kandasamy Logeeswari; Shubashini Krishnan Sripathi

2013-01-01

324

N-heterocyclic-carbene-catalyzed synthesis of 2-aryl indoles.  

Science.gov (United States)

A convergent and efficient transition-metal-free catalytic synthesis of 2-aryl-indoles has been developed. The interception of a highly reactive and transient aza-ortho-quinone methide by an acyl anion equivalent generated through N-hetereocyclic carbene catalysis is central to this successful strategy. High yields and a wide scope as well as the streamlined synthesis of a kinase inhibitor are reported. PMID:25044815

Hovey, M Todd; Check, Christopher T; Sipher, Alexandra F; Scheidt, Karl A

2014-09-01

325

Aminative umpolung synthesis of aryl vicinal diamines from aromatic aldehydes.  

Science.gov (United States)

In this paper an aminative umpolung synthesis of aryl vicinal diamines from aldehydes and N-Ts imines is described. Electrophilic aromatic aldehydes were smoothly converted into delocalized 2-azaallylanions via condensation with 2,2-diphenylglycine in methanol and subsequent decarboxylation in THF and underwent further reaction with N-Ts imines to give a variety of 1,2-diamine derivatives in good yields with high syn/anti diastereoselectivity. PMID:24742159

Liu, Xuliang; Gao, Ang; Ding, Lei; Xu, Juan; Zhao, Baoguo

2014-04-18

326

Synthesis of 3-Aryl Coumarin Derivatives Using Ultrasound  

Directory of Open Access Journals (Sweden)

Full Text Available Coumarins occupy an important place in the realm of natural products and synthetic organic chemistry. A fast and highly efficient green method for synthesizing 3-aryl coumarin derivatives from salicylaldehyde and phenyl acetyl chloride in the presence of tetrahydrofuran and K2CO3 using ultrasound irradiation is reported. Ultrasound assisted reactions have resulted in better yields and faster reaction time of the desired products than when prepared under conventional conditions. The resulting coumarin derivatives were characterized by IR spectrum.

Kandasamy Logeeswari

2013-02-01

327

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

2014-10-21

328

Synthesis, Spectral Analysis, In Vitro Microbiological Evaluation, and Molecular Docking Studies of Some Novel 1-(1-Aryl-1H-tetrazol-5-yl)-2-(piperidin-1-yl)ethanone Derivatives.  

Science.gov (United States)

A new series of novel heterocyclic compounds containing both tetrazoles and piperidine nuclei together, namely, 1-(1-aryl-1H-tetrazol-5-yl)-2-(piperidin-1-yl)ethanone (22-28), were synthesized by the treatment of the respective 2-chloro-1-(1-aryl-1H-tetrazol-5-yl)ethanone (15-21) with piperidine in acetonitrile for 6?h. A series of novel tetrazole substituted piperidine derivatives were synthesized and evaluated for their antimicrobial activity using serial dilution method. The structures of the synthesized compounds were characterized by IR, (1)H NMR, (13)C NMR, mass spectral data, and elemental analysis. Evaluation of antimicrobial activity shows that several compounds exhibit good activity when compared with the reference drug candidates and thus could be promising new lead molecules. PMID:24944827

Elavarasan, Thangasamy; Bhakiaraj, Durairaj Peter; Gopalakrishnan, Mannathusamy

2014-01-01

329

Computational Study on the Acid Catalyzed Reactions of Fluorine-Containing 2,4-Dialkoxy-3,4-dihydro-2H-pyrans with Aromatic Compounds  

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The reaction of 2,4-diethoxy-6-trifluoromethyl-3,4-dihydro-2H-pyran (1) with aromatic compounds in refluxing acetonitrile in the presence of p-toluenesulfonic acid gave the mixture of 4-aryl-2-trifluoromethyl-4H-pyrans (3) and 6-aryl-1,1,1-trifluorohexa-3,5-dien-2-ones (4). In contrast, the same reaction carried out in trifluoroacetic acid at ambient temperature afforded 4-aryl-2-ethoxy-6-trifluoromethyl-3,4-dihydro-2H-pyrans (2) selectively. These two types of reactions giving quite differen...

Norio Ota; Yasuhiro Kamitori; Ryusuke Shirai; Mizuki Hatakenaka; Etsuji Okada

2012-01-01

330

Synthesis and structure-activity relationships of novel 1-arylmethyl-3-aryl-1H-pyrazole-5-carbohydrazide hydrazone derivatives as potential agents against A549 lung cancer cells.  

Science.gov (United States)

A series of novel 1-arylmethyl-3-aryl-1H-pyrazole-5-carbohydrazide hydrazone derivatives were synthesized and the effects of all the compounds on A549 cell growth were investigated. The results showed that all compounds had almost inhibitory effects on the growth of A549 cells. The study on structure-activity relationships and prediction of lipophilicities of compounds showed that compounds with LogP values in the range of 4.12-6.80 had inhibitory effects on the growth of A549 cells, and among of them the hydrazone derived from salicylaldehyde had much more inhibitory effects. PMID:18313806

Xia, Yong; Fan, Chuan-Dong; Zhao, Bao-Xiang; Zhao, Jing; Shin, Dong-Soo; Miao, Jun-Ying

2008-11-01

331

Synthesis of Novel Aryl(heteroarylsulfonyl Ureas of Possible Biological Interest  

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Full Text Available The course of reaction of aryl and heteroaryl sulfonamides with diphenylcarbonate (DPC and 4-dimethylaminopyridine (DMAP was found to depend on the pKa of the sulfonamide used. Aryl sulfonamides with pKa ~ 10 gave 4-dimethylamino-pyridinium arylsulfonyl-carbamoylides, while the more acidic heteroaryl sulfonamides (pKa ~ 8 furnished 4-dimethylaminopyridinium heteroarylsulfonyl carbamates. Both the carbamoylides and carbamate salts reacted with aliphatic and aromatic amines with the formation of appropriate aryl(heteroarylsulfonyl ureas, and therefore, can be regarded as safe and stable substitutes of the hazardous and difficult to handle aryl(heteroarylsulfonyl isocyanates.

Maria Gdaniec

2010-02-01

332

?-Selective C-H Arylation of Pyrroles Leading to Concise Syntheses of Lamellarins C and I.  

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The first general ?-selective C-H arylation of pyrroles has been developed by using a rhodium catalyst. This C-H arylation reaction, which is retrosynthetically straightforward but results in unusual regioselectivity, could result in de novo syntheses of pyrrole-derived natural products and pharmaceuticals. As such, we have successfully synthesized polycyclic marine pyrrole alkaloids, lamellarins C and I, by using this ?-selective arylation of pyrroles with aryl iodides (C-H/C-I coupling) and a new double C-H/C-H coupling as key steps. PMID:25190257

Ueda, Kirika; Amaike, Kazuma; Maceiczyk, Richard M; Itami, Kenichiro; Yamaguchi, Junichiro

2014-09-24

333

N-aryl chromophore ligands for bright europium luminescence.  

Science.gov (United States)

Sterically hindered N-aryl-benzimidazole pyridine-2-carboxylic acids (aryl = phenyl, 4-biphenyl, 2-naphthyl) readily form homoleptic, neutral, nine-coordinate europium complexes which display efficient sensitized luminescence in solid state and in dichloromethane solution with quantum yields reaching 59% and have monoexponential and nearly temperature-independent lifetimes as long as 2.7 ms. The ligand-centered absorption band with a maximum at 321-342 nm and intensity (50-56) x 10(3) M(-1)cm(-1) ensures efficient harvesting of excitation light by the complexes. Variation of N-aryl chromophore enhances the ligand absorption at 250-350 nm without changing its triplet state energy which amounts to (19.2-21.3) x 10(3) cm(-1). Photophysical properties of europium complexes benefit from adequate protection of the metal by the ligands against non-radiative deactivation and efficient ligand-to-metal energy transfer exceeding 70%. A correlation is observed between the sensitized luminescence quantum yields of europium and the ligand triplet state energy; in certain cases it points to the presence of a second-sphere quenching of Eu(III) by co-crystallized water in the solid state. PMID:20302272

Shavaleev, Nail M; Eliseeva, Svetlana V; Scopelliti, Rosario; Bünzli, Jean-Claude G

2010-04-19

334

Anti-leishmanial evaluation of C2-aryl quinolines: mechanistic insight on bioenergetics and sterol biosynthetic pathway of Leishmania braziliensis.  

Science.gov (United States)

A series of diverse simple C2-aryl quinolines was synthesized de novo via a straightforward synthesis based on the acid-catalyzed multicomponent imino Diels-Alder reactions. Seven selected quinolines were evaluated at different stages of Leishmania braziliensis parasite. Among them, the 6-ethyl-2-phenylquinoline 5f was able to inhibit the growth of promastigotes of this parasite without affecting the mammalian cells viability and decreasing the number of intracellular L. braziliensis amastigotes on BMDM macrophages. The mechanism of action studied for the selected compound consisted in: (1) alteration of parasite bioenergetics, by disrupting mitochondrial electrochemical potential and alkalinization of acidocalcisomes, and (2) inhibition of ergosterol biosynthetic pathway in promastigote forms. These results validate the efficiency of quinoline molecules as leishmanicide compounds. PMID:23719286

Bompart, Daznia; Núñez-Durán, Jorge; Rodríguez, Daniel; Kouznetsov, Vladimir V; Meléndez Gómez, Carlos M; Sojo, Felipe; Arvelo, Francisco; Visbal, Gonzalo; Alvarez, Alvaro; Serrano-Martín, Xenón; García-Marchán, Yael

2013-07-15

335

Synthesis of some 3-(arylalkylthio)-4-alkyl/aryl-5-(4-aminophenyl)-4H-1,2,4-triazole derivatives and their anticonvulsant activity.  

Science.gov (United States)

A series of novel 3-[[(substituted phenyl)methyl]thio]-4-alkyl/aryl-5-(4-aminophenyl)-4H-1,2,4-triazoles 11-20 and several related Schiff's bases, 3-[[(substituted phenyl)-methyl]thio]-4-alkyl/aryl-5-[[[(substituted phenyl/5-nitro-2-furyl)methylene]amino]-phenyl]-4H-1,2,4-triazoles 21-31 were synthesized for evaluation of their biological properties. Structures of the synthesized compounds were confirmed by the use of their spectral data besides elemental analysis. All compounds were evaluated for their anticonvulsant activity by maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ) and neurotoxicity (NT) screens. A number of triazole derivatives, exhibited protection after intraperitoneal administration at the dose of 100 and 300 mg/kg in one or both models employed. Compounds 12, 13 and 14 were subjected to oral MES screening in rats at 30 mg/kg and were observed to protect 50% of the animals employed in the experiment. Antimicrobial and antituberculosis activity of these compounds 11-31 were also screened. Some of the tested compounds showed marginal activity against M. tuberculosis H37 Rv. PMID:15544794

Küçükgüzel, Ilkay; Güniz Küçükgüzel, S; Rollas, Sevim; Otük-Sani?, Gülten; Ozdemir, Osman; Bayrak, Ibrahim; Altu?, Tuncay; Stables, James P

2004-11-01

336

TBAHS CATALYZED COUPLING REACTIONS OF ARYL IODIDES AND ARYL BROMIDES WITH THIOLS UNDER SOLVENT FREE CONDITIONS TBAHS katalysierten Kupplungen von Aryliodiden und-Arylbromiden mit Thiolen unter lösungsmittelfreien freien Bedingungen  

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Full Text Available A recyclable and efficient Tetrabutylammonium hydrogensulfate (TBAHS catalysed coupling reaction of aryl halides (iodide and bromide with aryl and alkyl thiols under solvent-free conditions were developed.

Gajendera Singha, Ajay kumarb , Sakshi Malikc, Preeti Chaudharyd

2013-04-01

337

Direct (hetero)arylation: a new tool for polymer chemists.  

Science.gov (United States)

The coupling of aryl halides with catalytically activated aryl C-H bonds provides a desirable and atom-economical alternative to standard cross-coupling reactions for the construction of new C-C bonds. The reaction, termed direct (hetero)arylation, is believed to follow a base-assisted, concerted metalation-deprotonation (CMD) pathway. During this process, carboxylate or carbonate anions coordinate to the metal center, typically palladium, in situ and assist in the deprotonation transition state. Researchers have employed this methodology with numerous arenes and heteroarenes, including substituted benzenes, perfluorinated benzenes, and thiophenes. Thiophene substrates have demonstrated high reactivity toward C-H bond activation when appropriately substituted with electron-rich and/or electron-deficient groups. Because of the pervasive use of thiophenes in materials for organic electronics, researchers have used this chemistry to modularly prepare conjugated small molecules and, more recently, conjugated polymers. Although optimization of reaction conditions such as solvent system, phosphine ligand, carboxylate additives, temperature, and time is necessary for efficient C-H bond reactivity of each monomer, direct (hetero)arylation polymerization (DHAP) can afford high yielding polymeric materials with elevated molecular weights. The properties of these materials often rival those of polymers prepared by traditional methods. Moreover, DHAP provides a facile means for the synthesis of polymers that were previously inaccessible or difficult to prepare due to the instability of organometallic monomers. The major downfall of direct (hetero)arylation, however, is the lack of C-H bond selectivity, particularly for thiophene substrates, which can result in cross-linked material during polymerization reactions. Further fine-tuning of reaction conditions such as temperature and reaction time may suppress these unwanted side reactions. Alternatively, new monomers can be designed where other reactive bonds are blocked, either sterically or by substitution with unreactive alkyl or halogen groups. In this Account, we illustrate these methods and present examples of DHAP reactions that involve the preparation of common homopolymers used in organic electronics (P3HT, PEDOT, PProDOT), copolymers formed by activation of electron-rich (bithiophene, fused bithiophenes) and electron-deficient monomers (TPD, 1,2,4,5-tetrafluorobenzene, 2,2'-bithiazole). Our group is optimizing these reactions and developing ways to make DHAP a common atom-economical synthetic tool for polymer chemists. PMID:23544354

Mercier, Lauren G; Leclerc, Mario

2013-07-16

338

Microwave-mediated and customery synthesis of N-benzoyl- or N-substituted benzoyl-N,N'-dialkylureas from arylcarboxylic acids and N,N'-disubstituted carbodiimides under solvent-free conditions  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Uma síntese fácil, eficiente e rápida de N-benzoil-(e benzoil N-substituída)-N,N'-dialquiluréias foi realizada com bons rendimentos em condições livre de solvente. Primeiramente, a reação entre um ácido carboxílico e uma carbodiimida dissubstituída foi feita empregando radiação de microondas, e depo [...] is a mesma reação foi realizada sob aquecimento convencional. Os rendimentos são comparáveis em ambos os casos. Abstract in english An easy, efficient and quick synthesis of N-benzoyl-(and N-substituted benzoyl)-N,N'dialkylureas, in good yields, under solvent-free conditions is described. First, the reaction between a carboxylic acid and a disubstituted carbodiimide was carried out employing microwave radiation, and later on the [...] same reaction was performed separately under dry heating without any radiation. The yields are comparable in both cases.

Ricardo A. W., Neves Filho; Ronaldo N. de, Oliveira; Rajendra M., Srivastava.

1410-14-01

339

Microwave-mediated and customery synthesis of N-benzoyl- or N-substituted benzoyl-N,N'-dialkylureas from arylcarboxylic acids and N,N'-disubstituted carbodiimides under solvent-free conditions  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Uma síntese fácil, eficiente e rápida de N-benzoil-(e benzoil N-substituída)-N,N'-dialquiluréias foi realizada com bons rendimentos em condições livre de solvente. Primeiramente, a reação entre um ácido carboxílico e uma carbodiimida dissubstituída foi feita empregando radiação de microondas, e depo [...] is a mesma reação foi realizada sob aquecimento convencional. Os rendimentos são comparáveis em ambos os casos. Abstract in english An easy, efficient and quick synthesis of N-benzoyl-(and N-substituted benzoyl)-N,N'dialkylureas, in good yields, under solvent-free conditions is described. First, the reaction between a carboxylic acid and a disubstituted carbodiimide was carried out employing microwave radiation, and later on the [...] same reaction was performed separately under dry heating without any radiation. The yields are comparable in both cases.

Ricardo A. W., Neves Filho; Ronaldo N. de, Oliveira; Rajendra M., Srivastava.

340

Bulky N-substituted 1,3-benzazaphospholes: access via Pd-catalyzed C-N and C-P cross coupling, lithiation, and conversion to novel P=C-PtBu2 hybrid ligands.  

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The syntheses of novel bulky N-substituted 1,3-benzazaphospholes are presented, together with their reactions with tert-butyllithium and coupling with tBu 2PCl to novel P, P'-hybrid ligands that combine the highly basic and bulky di- tert-butylphosphanyl group with pi-acidic low-coordinated phosphorus. The syntheses start with the preparation of new N-secondary 2-bromoanilines 1 by reduction of N-acyl 2-bromoanilides or more generally by Pd-catalyzed selective monoamination of o-dibromobenzene, followed by Pd-catalyzed C-P coupling with P(OEt) 3 to the respective 2-anilino-phosphonates 2. The next steps are reduction to 2-phosphanylanilines 3 and condensation with Me 2NCH(OMe) 2, which leads via phosphaalkenes 4 to the corresponding N-substituted benzazaphospholes 5. The reaction with tBuLi depends on the steric demand of the N substituent. Methyl, neopentyl-, and mesityl-derivatives were converted to P=C Li species 6 and coupled with tBu 2PCl to novel P=C-P tBu 2 ligands 7, whereas N-adamantyl and N-2,6-diisopropylphenyl-derivatives prefer addition of tBuLi at the PC bond to form dihydroderivatives. The chemical shifts of the low-coordinated phosphorus of 5 and 7 were found to reflect electronic and steric effects of the N substituents. The comparison of the crystal structures of N-neopentyl-1,3-benzazaphospholes 5 and 7 gives evidence of steric repulsion between the adjacent di- tert-butyl and neopentyl groups by the preferred anti orientation of the P- tert-butyl groups and moderate deviations of C2 and P3 of 7b from the ring plane. PMID:18610971

Aluri, Bhaskar Reddy; Kindermann, Markus K; Jones, Peter G; Dix, Ina; Heinicke, Joachim

2008-08-01

 
 
 
 
341

An Ef?cient Synthesis of 1-Aryl-3-(indole-3-yl-3-(2-aryl-1,2,3-triazol-4-ylpropan-1-one Catalyzed by a Brønsted Acid Ionic Liquid  

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Full Text Available An efficient synthesis of novel 1-aryl-3-(indole-3-yl-3-(2-aryl-1,2,3-triazol-4-ylpropan-1-ones from indoles and 1-aryl-3-(2-aryl-1,2,3-triazol-4-ylpropan-1-one using a Brønsted acid ionic liquid [Sbmim][HSO4] as catalyst is described. Satisfactory results with excellent yields and short reaction time were obtained in the experiments. The catalyst could be recovered conveniently and reused efficiently.

Chuan-Ji Yu

2010-12-01

342

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

343

Synthesis and antileishmanial activity of new 1-aryl-1H-pyrazole-4-carboximidamides derivatives  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A quimioterapia para as leishmanioses, doenças causadas por protozoários do gênero Leishmania, ainda permanece ineficiente em diversos tratamentos. Portanto, existe a necessidade de pesquisa por novos fármacos. Nesse trabalho, foram sintetizados derivados 1-aril-1H-pirazol-4-carboximidamidas, avalia [...] das as atividades leishmanicida e os efeitos citotóxicos in vitro, e realizado um estudo de relação estrutura-atividade (REA) com a série de compostos. O composto 2 apresentou um perfil de atividade que pode ser melhorado através de estratégias de modificação molecular da química medicinal. Abstract in english 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.

Maurício S. dos, Santos; Adriana O, Gomes; Alice M. R, Bernardino; Marcos C. de, Souza; Misbahul A, Khan; Monique A. de, Brito; Helena C, Castro; Paula A, Abreu; Carlos R, Rodrigues; Rosa M. M. de, Léo; Leonor L, Leon; Marilene M, Canto-Cavalheiro.

2011-02-01

344

Hydrogen bonding patterns in 3,5-diamino-6-aryl triazines  

Science.gov (United States)

The crystal structure of two related 1,2,4-triazine derivatives, C 9H 7N 5Cl 2·H 2O ( 1) and C 12H 14N 5Cl 2+·CH 3SO 3-·H 2O ( 2) that have different biological effects, have been determined. Lamotrigine (Lamictal, 1) is a novel anticonvulsant and BWA256C ( 2) is a class 1 antiarrythmic drug. The dihedral angles between the least-squares planes of almost exactly planar phenyl and triazine rings are 76.42(6) and 76.08(6)°, for compounds 1 and 2, respectively. In 2, protonation takes place at the iminium nitrogen atom, thus suggesting the importance of resonance through the triazine ring. This resonance is also confirmed by the pattern of bond lengths and angles. Extensive networks of hydrogen bonds, in which all molecular species are involved, rule the crystal packing in both compounds. The analysis of hydrogen bond networks in other 3,5-diamino-6-aryl derivatives suggests that there is a strong influence of co-crystallizing solvent molecule on the nature of resulting hydrogen bond topology.

Kubicki, M.; Codding, P. W.

2001-08-01

345

Synthesis and antileishmanial activity of new 1-aryl-1H-pyrazole-4-carboximidamides derivatives  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A quimioterapia para as leishmanioses, doenças causadas por protozoários do gênero Leishmania, ainda permanece ineficiente em diversos tratamentos. Portanto, existe a necessidade de pesquisa por novos fármacos. Nesse trabalho, foram sintetizados derivados 1-aril-1H-pirazol-4-carboximidamidas, avalia [...] das as atividades leishmanicida e os efeitos citotóxicos in vitro, e realizado um estudo de relação estrutura-atividade (REA) com a série de compostos. O composto 2 apresentou um perfil de atividade que pode ser melhorado através de estratégias de modificação molecular da química medicinal. Abstract in english 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.

Maurício S. dos, Santos; Adriana O, Gomes; Alice M. R, Bernardino; Marcos C. de, Souza; Misbahul A, Khan; Monique A. de, Brito; Helena C, Castro; Paula A, Abreu; Carlos R, Rodrigues; Rosa M. M. de, Léo; Leonor L, Leon; Marilene M, Canto-Cavalheiro.

346

New synthesis and antiparasitic activity of model 5-aryl-1-methyl-4-nitroimidazoles.  

Science.gov (United States)

A number of 5-aryl-1-methyl-4-nitroimidazoles 5a-f have been synthesized in good yields by the Suzuki coupling reaction between 5-chloro-1-methyl-4-nitroimidazole (3) and arylboronic acids 4a-f, aided by dichlorobis-(triphenylphosphine)palladium(II), K(2)CO(3, )and tetrabutylammonium bromide in water at 70-80 degrees C. Compounds 5a-f were characterized by elemental analysis, NMR and MS spectral data. On the basis of in vitro screening data, 5-(3-chlorophenyl)-1-methyl-4-nitro-1H-imidazole (5f) exhibited potent lethal activity against Entamoeba histolytica and Giardia intestinalis with IC(50) = 1.47 microM/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 IC(50 ) values in the 1.72-4.43 microM/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. PMID:19701122

Saadeh, Haythem A; Mosleh, Ibrahim M; El-Abadelah, Mustafa M

2009-01-01

347

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 µM/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 µM/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

348

MICROWAVE ASSISTED SYNTHESIS OF 6-BENZOYL-5-METHYL-2-[(Z-1-ARYL METHYLIDENE]-2,3-DIHYDROFURO [3’,2’ :4,5] BENZO[b] FURAN-3-ONES AND THEIR ANTIBACTERIAL ACTIVITY Mikrowellen unterstützte Synthese von 6-Benzoyl-5-METHYL-2-[(Z-1-ARYL Methyliden] -2,3-DIHYDROFURO [3", 2": 4,5] benzo [b] furan-3-one und Ihre antibakterielle Aktivität  

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Full Text Available A series of 6-Benzoyl-5-methyl-2-[(Z-1-arylmethylidene]-2,3-dihydrofuro[3’,2’:4,5] benzo[b]furan-3-ones have been prepared by an efficient oxidation of (E-1-(2-Benzoyl- 6-hydroxy-3-methyl benzo[b] furan-5-yl-3-aryl-2-propen-1-ones with cupric bromide or mercuric acetate under microwave irradiation. The structures of newly synthesized compounds have been established on the basis of elemental analysis, IR, 1H-NMR,13 C-NMR and mass spectral data. All the compounds were screened for their antibacterial activity.

Ashok D, Sudershan K and Khalilullah M

2011-10-01

349

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)

350

Molecular and crystal structures of some novel derivatives of 3-aryl-7-arylidene-3,3a,4,5,6,7-hexahydroindazoles  

International Nuclear Information System (INIS)

The stereochemical aspects of the interaction of 2,6-bis(arylidene)-cyclohexanone and 2,6-bis(arylidene)-3-methylcyclohexanone with arylhydrazine (aryl is phenyl or 4-nitrophenyl) and methylhydrazine are investigated using X-ray diffraction analysis. The molecular structure of the 3-aryl-7-arylidene-3,3a,4,5,6,7-hexahydroindazoles synthesized is determined by X-ray diffraction analysis for the first time. It is established that the stereochemistry of the products of the interaction between the cyclohexanone derivatives and arylhydrazines depends on the electronic nature of the substituent in the aryl group. Two regioisomeric products with different positions of the methyl group in the cyclohexane ring with respect to the arylidene fragment are synthesized by the reaction of 2,6-bis(4-methoxybenzylidene)-3-methylcyclohexanone with methylhydrazine. The influence of the substituents at the nitrogen atom of the pyrazoline ring on the intramolecular electronic interactions and the geometry of the heterocycle in the compounds under investigation is discussed

351

Base-promoted aryl-bromine bond cleavage with cobalt(II) porphyrins via a halogen atom transfer mechanism.  

Science.gov (United States)

Aryl-bromine bonds are successfully cleaved by cobalt(II) porphyrins in basic media to give Co(por)Ar (por = porphyrin) in good yields. Mechanistic studies suggested that the aryl-bromine bond is cleaved through a halogen atom transfer mechanism, which is different from the aryl-halogen bond cleavage mechanism with other group 9 metalloporphyrins. PMID:24699823

Liu, Chun Ran; Qian, Ying Ying; Chan, Kin Shing

2014-06-01

352

Mild and general palladium-catalyzed synthesis of methyl aryl ethers enabled by the use of a palladacycle precatalyst.  

Science.gov (United States)

A general method for the Pd-catalyzed coupling of methanol with (hetero)aryl halides is described. The reactions proceed under mild conditions with a wide range of aryl and heteroaryl halides to give methyl aryl ethers in high yield. PMID:23883393

Cheung, Chi Wai; Buchwald, Stephen L

2013-08-01

353

[Synthesis and biological activity of aryl S-beta-glycosides of 1-thio-N-acetylmuramyl-L-alanyl-D-isoglutamine].  

Science.gov (United States)

Phenyl, p-tolyl, and p-tert-butylphenyl beta-1-thio-N-acetylglucosaminides were synthesized by the treatment of thiophenols with peracetate of alpha-D-glucosaminyl chloride in the presence of triethylamine or under the conditions of phase-transfer catalysis with quaternary ammonium salts. The compounds synthesized were used for obtaining of glycosides of 4,6-O-isopropylidene-N-acetylmuramic acid, which were coupled with L-Ala-D-Glu(NH2)-OBzl and then deprotected to obtain the target aryl beta-thioglycosides of N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP). The aryl beta-thioglycosides of MDP were found to stimulate an antibacterial resistance toward Staphylococcus aureus in mice. The reliable induction of the spontaneous activity of natural killers in the population of blood mononuclear cells was observed only for phenyl beta-thio-MDP at a dose of 200 microg/ml. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2008, vol. 34, no. 2; see also http://www.maik.ru. PMID:18522281

Zemliakov, A E; Tsikalova, V N; Azizova, L R; Chirva, V Ia; Mulik, E L; Shkalev, M V; Kaliuzhin, O V; Kiselevski?, M V

2008-01-01

354

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

Directory of Open Access Journals (Sweden)

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

355

Frequency of the functionally relevant aryl hydrocarbon receptor repressor (AhRR) Pro185Ala SNP in Papua New Guinea.  

Science.gov (United States)

The diverse cultural and social habits of the Papua New Guinea (PNG) population include betel quid chewing and more recently smoking. The formation of DNA adducts from betel quid is mediated by the cytochrome P450 (CYP) enzymes, including CYP1A2. The tobacco smoke compounds can induce CYP1A2. The transcription factor AhR (aryl hydrocarbon receptor) is involved in the regulation of CYP1A2 expression. AhR activity is itself regulated by other transcription factors, including the aryl hydrocarbon receptor repressor (AhRR). The AhRR Pro185Ala (rs2292596; 565C>G) minor allele was recently associated with a lower AhR repressor activity, leading to a higher CYP1A2 inducibility. We investigated AhRR Pro185Ala SNP in the East Sepik populations in PNG and found a high frequency of 53.4% of the minor allele, significantly different from other Asian populations. We can hypothesize that a high frequency of the AhRR SNP can be a risk factor in the incidence of oral cancer and other neoplasias in PNG due to higher inducibility of CYP1A2. The potential role of AhRR pharmacogenetics in the risk of developing cancers associated with betel quid chewing and smoking should be addressed and clarified in future epidemiological studies in PNG. PMID:23648678

Cavaco, Isa; Hombhanje, Francis Wanak; Gil, José Pedro; Kaneko, Akira

2013-01-01

356

Ligand-free copper-catalyzed C-S coupling of aryl iodides and thiols.  

Science.gov (United States)

A protocol for the copper-catalyzed aryl-sulfur bond formation between aryl iodides and thiophenols is reported. The reaction is catalyzed by a low amount (1-2.5 mol %) of readily available and ligand-free copper iodide salt. A variety of diaryl thioethers are synthesized under relatively mild reaction conditions with good chemoselectivity and functional group tolerance. PMID:18570479

Sperotto, Elena; van Klink, Gerard P M; de Vries, Johannes G; van Koten, Gerard

2008-07-18

357

Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester  

Directory of Open Access Journals (Sweden)

Full Text Available An aryl substrate with dual functionality consisting of a nitrile oxide and a pinacolyl boronate ester was prepared by mild hypervalent iodine oxidation (diacetoxyiodobenzene of the corresponding aldoxime, without decomposition of the boronate functionality. The nitrile oxide was trapped in situ with a variety of dipolarophiles to yield aryl isoxazolines with the boronate ester function intact and available for subsequent reaction.

Sarah L. Harding

2012-04-01

358

Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An aryl substrate with dual functionality consisting of a nitrile oxide and a pinacolyl boronate ester was prepared by mild hypervalent iodine oxidation (diacetoxyiodobenzene) of the corresponding aldoxime, without decomposition of the boronate functionality. The nitrile oxide was trapped in situ with a variety of dipolarophiles to yield aryl isoxazolines with the boronate ester function intact and available for subsequent reaction.

Harding, Sarah L.; Marcuccio, Sebastian M.; Paul Savage, G.

2012-01-01

359

Efficient synthesis of 5-substituted 2-aryl-6-cyanoindolizines via nucleophilic substitution reactions  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract 2-Aryl-6-cyano-7-methyl-5-indolizinones were successfully converted into 2-aryl-5-chloro-6-cyano-7-methylindolizines. The obtained 5-chloroindolizines readily underwent nucleophilic substitution at position 5 leading in high yields to novel 5-functionalised indolizines.

Vasilevich Natalya I

2005-10-01

360

A phosphine-free Pd catalyst for the selective double carbonylation of aryl iodides.  

Science.gov (United States)

The first phosphine-free Pd-catalysed double carbonylation of aryl iodides is reported as a general and practical method, giving excellent conversions and selectivities for a wide range of aryl iodides and amine nucleophiles under atmospheric CO pressure. PMID:22190125

de la Fuente, Verónica; Godard, Cyril; Zangrando, Ennio; Claver, Carmen; Castillón, Sergio

2012-02-01

 
 
 
 
361

Palladium-catalyzed C-H arylation using phosphoramidate as a directing group at room temperature.  

Science.gov (United States)

This communication describes the first phosphoramidate directing group for synthetically useful arylation. Remarkably, the nature of a new directing group drives selective C-H bond activation to afford diverse N-aryl phosphoramidates in good to excellent yields at room temperature. PMID:23683086

Chary, Bathoju Chandra; Kim, Sunggak; Park, Youngchul; Kim, Jinsik; Lee, Phil Ho

2013-06-01

362

Aryl nitrile oxide cycloaddition reactions in the presence of pinacol boronic acid ester.  

Science.gov (United States)

An aryl substrate with dual functionality consisting of a nitrile oxide and a pinacolyl boronate ester was prepared by mild hypervalent iodine oxidation (diacetoxyiodobenzene) of the corresponding aldoxime, without decomposition of the boronate functionality. The nitrile oxide was trapped in situ with a variety of dipolarophiles to yield aryl isoxazolines with the boronate ester function intact and available for subsequent reaction. PMID:22563358

Harding, Sarah L; Marcuccio, Sebastian M; Savage, G Paul

2012-01-01

363

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

364

Oxidative addition of aryl chlorides to monoligated palladium(0): A DFT-SCRF study  

DEFF Research Database (Denmark)

Oxidative addition of aryl chlorides to palladium has been investigated by hybrid density functional theory methods (B3LYP), including a continuum model describing the solvent implicitly. A series of para-substituted aryl chlorides were studied to see the influence of electronic effects on the reaction. It was found that the experimentally observed higher reactivity of the more electron deficient aryl chlorides is due to their ability to accept back-donation from Pd-0 and form reasonably strong pre-reactive complexes. This effect is less pronounced in the transition state; when it is measured from the pre-reactive complex, the barrier to oxidative addition is actually higher for the electron-deficient aryl chlorides, but the overall reaction barrier is still lower than for the electron-rich aryl chlorides.

Ahlquist, Mårten Sten Gösta; Norrby, Per-Ola

2007-01-01

365

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 (ppaper 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

366

Highly dispersed pd catalyst locked in knitting aryl network polymers for Suzuki-Miyaura coupling reactions of aryl chlorides in aqueous media.  

Science.gov (United States)

Highly dispersed palladium chloride catalysts locked in triphenylphosphine-functionalized knitting aryl network polymers (KAPs) are developed and exhibit excellent activity under mild conditions in the Suzuki-Miyaura cross-coupling reactions of aryl chlorides in aqueous media. This work highlights that the microporous polymers not only play the role of support materials, but also protect the Pd species from aggregation and precipitation, hence, positively effect the catalysis activity. PMID:22674537

Li, Buyi; Guan, Zhenhong; Wang, Wei; Yang, Xinjia; Hu, Jianglin; Tan, Bien; Li, Tao

2012-07-01

367

A Well-Defined (POCOP)Rh Catalyst for the Coupling of Aryl Halides with Thiols.  

Science.gov (United States)

This article describes a well-defined pincer-Rh catalyst for C-S cross-coupling reactions. (POCOP)Rh(H)(Cl) serves as an active precatalyst for the coupling of aryl chlorides and bromides with aryl and alkyl thiols under reasonable conditions (3% mol cat., 110 °C, 2-24 h, >90% yield). For select substrates, >90% yields were obtained with catalyst loading as low as 0.1%. Key mechanistic intermediates have been isolated and fully characterized, including (POCOP)Rh(Ph)(SPh) (6a) and (POCOP)Rh(SPh2) (6b). The aryl/bis(phosphinite) (POCOP)Rh system has been shown to favor aryl thiolate reductive elimination at elevated temperatures and in some cases at room temperature, compared with the analogous diarylamido/bis(phosphine) (PNP)Rh pincer system. Concerted reductive elimination has been studied with 6a directly and in the presence of aryl bromide and aryl chloride traps. This investigation demonstrates a clear rate dependence on aryl chloride concentration during catalysis, a dependence that is absent when using aryl bromides. The rate of catalysis is dramatically reduced or brought to zero for ortho-tolyl halides, which can be traced to slower C-S coupling and slower carbon-halogen oxidative addition for ortho-substituted aryls. The influence of the sterics in the thiol component is less straightforward. The S-H oxidative addition product (POCOP)Rh(H)(SPh) (16) has been fully characterized and its reactivity has been examined, resulting in the isolation of the sodium-thiolate adduct (POCOP)Rh(NaSPh) (19). The solid-state structure of 19 shows Na interactions not only with sulfur, but also with a neighboring Rh and the chelating aryl carbon of the pincer framework. The reactivity of 16 and 19 indicates that these potential side products should not hinder catalysis. PMID:25260114

Timpa, Samuel D; Pell, Christopher J; Ozerov, Oleg V

2014-10-22

368

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

369

Functionalization of Rhenium Aryl Bonds by O-Atom Transfer  

Energy Technology Data Exchange (ETDEWEB)

Aryltrioxorhenium (ArReO{sub 3}) has been demonstrated to show rapid oxy-functionalization upon reaction with O-atom donors, YO, to selectively generate the corresponding phenols in near quantitative yields. {sup 18}O-Labeling experiments show that the oxygen in the products is exclusively from YO. DFT studies reveal a 10.7 kcal/mol barrier (Ar = Ph) for oxy-functionalization with H{sub 2}O{sub 2} via a Baeyer?Villiger type mechanism involving nucleophilic attack of the aryl group on an electrophilic oxygen of YO coordinated to rhenium.

Bischof, Steven M; Cheng, Mu-Jeng; Nielsen, Robert J; Gunnoe, T. Brent; Goddard, William A; Periana, Roy A

2011-01-01

370

?-Aryl-?-nitro-?,?-enals as heterodienes and dienophiles.  

Science.gov (United States)

As demonstrated with the ?-(2-furyl)-substituted analogue 1b, ?-aryl-?-nitro-?,?-enals (1) behave as heterodienes against enamines and enol ethers using their enal unit (e.g., 1b ? 12). ?-Nitro-?,?-enals can act as well as highly reactive dienophiles to render adducts endowed with nitrogenated quaternary centers (e.g., 1b ? 15a). A hetero-Diels-Alder (HDA)/Diels-Alder (DA) sequence from 1b also proved feasible on serial treatment with ethyl vinyl ether and Danishefsky's diene (1b ? 14). PMID:25181678

Lago-Santomé, Hugo; Martínez-Bescos, Patricia; Fernández-González, Marta; Ozores-Viturro, Lidia; Cagide-Fagín, Fernando; Alonso, Ricardo

2014-09-19

371

Modification of PEEK model compounds and PEEK film by energetic heavy ion and ultraviolet irradiations  

Science.gov (United States)

To prepare nuclear track membranes from poly(aryl ether ether ketone) (PEEK) film, we first determined the modifications induced by heavy ion and UV irradiations in this polymer and two of its model compounds, paraphenoxy benzophenone (PPB) and diphenoxy benzophenone (DPB). This article displays the first results obtained by SEC, HPLC, DSC, FTIR, UV and 13C NMR.

Ferain, E.; Legras, R.

1993-10-01

372

Practical synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides via conventional and decarboxylative copper-free Sonogashira coupling reactions.  

Science.gov (United States)

Two efficient protocols for the palladium-catalyzed synthesis of aryl-2-methyl-3-butyn-2-ols from aryl bromides in the absence of copper were developed. A simple catalytic system consisting of Pd(OAc)2 and P(p-tol)3 using DBU as the base and THF as the solvent was found to be highly effective for the coupling reaction of 2-methyl-3-butyn-2-ol (4) with a wide range of aryl bromides in good to excellent yields. Analogously, the synthesis of aryl-2-methyl-3-butyn-2-ols was performed also through the decarboxylative coupling reaction of 4-hydroxy-4-methyl-2-pentynoic acid with aryl bromides, using a catalyst containing Pd(OAc)2 in combination with SPhos or XPhos in the presence of tetra-n-butylammonium fluoride (TBAF) as the base and THF as the solvent. Therefore, new efficient approaches to the synthesis of terminal acetylenes from widely available aryl bromides rather than expensive iodides and using 4 or propiolic acid rather than TMS-acetylene as inexpensive alkyne sources are described. PMID:24605159

Caporale, Andrea; Tartaggia, Stefano; Castellin, Andrea; De Lucchi, Ottorino

2014-01-01

373

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

374

Highvalent and organometallic technetium and rhenium compounds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis contains synthesis and characterization of mixed anhydrides of pertechnetic acid which may possibly serve as precursors for [TcO3]+ complexes, and the synthesis of new organometallic technetium complexes containing carbonyl ligands and N-heterocyclic carbenes as well as the first syntheses of technetium aryls. In the first section, the synthesis, characterization and stability of [R3EOTcO3] (E = C, Si, Ge, Sn, Pb; R = Me, iPr, tBu, Ph) and related compounds are discussed. The ...

Oehlke, Elisabeth

2010-01-01

375

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Sahu S; Mishra S; Mohanta R; Pattanayak S; Panda C

2006-01-01

376

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

377

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

378

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

Energy Technology Data Exchange (ETDEWEB)

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 BuAd{sub 2}P and t-BuOK in DMF at 120 .deg. C after 15 h.

Yang, Hai; Zeng, Jian; Liu, Huajie; Yi, Bing [College of Chemistry and Chemical Engineering/Hunan Institute of Engineering, Xiangtan (China); Zheng, Zhishuo [Guangdong Univ. of Education, Guangzhou (Korea, Republic of)

2012-04-15

379

Synthesis, biological evaluation, and docking studies of 3-(substituted)-aryl-5-(9-methyl-3-carbazole)-1H-2-pyrazolines as potent anti-inflammatory and antioxidant agents.  

Science.gov (United States)

A novel series of 3-(substituted)-aryl-5-(9-methyl-3-carbazole)-1H-2-pyrazolines (5a-o) has been synthesized and the structures of newly synthesized compounds were characterized by IR, (1)H NMR and mass spectral analysis. All the synthesized compounds were evaluated for their in vitro and in vivo anti-inflammatory activity, and also for their antioxidant activity. Compounds 5b, 5c, 5d and 5n were found to be selective COX-2 inhibitors. Compound 5c was found to potent inhibitor of the carrageenin induced paw edema in rats. Most of the compounds exhibited good DPPH and superoxide radical scavenging activity, while compounds 5c, 5d, 5i and 5k exhibited good hydroxyl radical scavenging activity. Molecular docking result, along with the biological assay data, suggested that compound 5c was a potential anti-inflammatory agent. PMID:22901385

Bandgar, Babasaheb P; Adsul, Laxman K; Chavan, Hemant V; Jalde, Shivkumar S; Shringare, Sadanand N; Shaikh, Rafique; Meshram, Rohan J; Gacche, Rajesh N; Masand, Vijay

2012-09-15

380

Syntheses and Biological Activities of 6-Aryl-3-(3-hydroxy- propyl-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines  

Directory of Open Access Journals (Sweden)

Full Text Available A series of 6-aryl-3-(3-hydroxypropyl-7H-1,2,4-triazolo[3,4-b][1,3,4]-thia-diazines were synthesized by the reaction of 4-amino-3-(3-hydroxypropyl-5-mercapto-1,2,4-triazole (1 with substituted ?-haloacetophenones. Their structures were confirmed by elemental analysis, IR, 1H-NMR, and 13C-NMR. Tests of plant growth regulating effects showed that the title compounds display remarkable inhibitory activities on the growth of radish and wheat.

Hai-le Zhang

2007-03-01

 
 
 
 
381

Diversity-oriented syntheses: coupling reactions between electron-deficient olefins and aryl aldehydes via C(sp2)-H functionalization.  

Science.gov (United States)

A diversity-oriented syntheses by coupling three electron-deficient olefins (vinyl sulfonamides, methacrylamides, and methyl acrylates, respectively) with aryl aldehydes via C(sp(2))-H functionalization were reported. These reactions gave four different skeletal products respectively under environment-friendly and mild conditions. All these reactions are highly regioselective and effective, very suitable for the preparation of synthetic building blocks and compound library, the results will enrich current coupling chemistry of olefins with aldehydes and can be applied to other chemistry areas as well. PMID:25062387

Niu, Ben; Xu, Lei; Xie, Ping; Wang, Min; Zhao, Wannian; Pittman, Charles U; Zhou, Aihua

2014-09-01

382

Synthesis and pharmacological study of 1-acetyl/propyl-3-aryl-5-(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)-2-pyrazoline.  

Science.gov (United States)

A series of 1-acetyl/propyl-3-aryl-5-(5-chloro-3-methyl-1-phenyl-1H-pyrazol-4-yl)-2-pyrazolines were synthesized in one step by condensing suitably substituted propenones, hydrazine and acetic/propionic acid. The newly synthesized pyrazolines were characterized by analytical and spectral data. The new compounds were screened for analgesic and anti-inflammatory activity and most of them showed good activity comparable with that of standard drugs Pentazocin and Diclofinac sodium respectively. PMID:20702008

Girisha, K S; Kalluraya, Balakrishna; Narayana, Vijaya; Padmashree

2010-10-01

383

Brønsted acid catalyzed, conjugate addition of ?-dicarbonyls to in situ generated ortho-quinone methides--enantioselective synthesis of 4-aryl-4H-chromenes.  

Science.gov (United States)

We describe herein a catalytic, enantioselective process for the synthesis of 4H-chromenes which are important structural elements of many natural products and biologically active compounds. A sequence comprising a conjugate addition of ?-diketones to in situ generated ortho-quinone methides followed by a cyclodehydration reaction furnished 4-aryl-4H-chromenes in generally excellent yields and high optical purity. A BINOL-based chiral phosphoric acid was employed as a Brønsted acid catalyst which converted ortho-hydroxy benzhydryl alcohols into hydrogen-bonded ortho-quinone methides and effected the carbon-carbon bond-forming event with high enantioselectivity. PMID:24938645

El-Sepelgy, Osama; Haseloff, Stefan; Alamsetti, Santosh Kumar; Schneider, Christoph

2014-07-21

384

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)

385

Principal component analysis for verifying 1H NMR spectral assignments. The case of 3-aryl (1,2,4)-oxadiazole-5-carbohydrazide benzylidene  

International Nuclear Information System (INIS)

The 1H NMR data set of a series of 3-aryl (1,2,4)-oxadiazole-5-carbohydrazide benzylidene derivatives synthesized in our group was analyzed using the chemometric technique of principal component analysis (PCA). Using the original 1H NMR data PCA allowed identifying some misassignments of the proton aromatic chemical shifts. As a consequence of this multivariate analysis, nuclear Overhauser difference experiments were performed to investigate the ambiguity of other assignments of the ortho and meta aromatic hydrogens for the compound with the bromine substituent. The effect of the 1,2,4-oxadiazole group as an electron acceptor, mainly for the hydrogens 12,13, has been highlighted. (author)

386

Arylation, alkenylation, and alkylation of 2-halopyridine N-oxides with grignard reagents: a solution to the problem of C2/C6 regioselective functionalization of pyridine derivatives.  

Science.gov (United States)

A facile arylation, alkenylation, and alkylation of functionalized 2-halopyridine N-oxides with various Grignard reagents was developed. It represented a highly efficient and selective C-H bond functionalization of pyridine derivatives in the presence of reactive C-Cl or C-Br bonds. Using Cl or Br as a blocking group, C2/C6 site-controllable functionalization of pyridine derivatives has been achieved. Various pyridine compounds can be prepared as illustrated in the total syntheses of Onychine, dielsine, and PARP-1 inhibitor GPI 16539. PMID:23390982

Zhang, Song; Liao, Lian-Yan; Zhang, Fang; Duan, Xin-Fang

2013-03-15

387

Silicon dioxide surfaces with aryl interaction sites for chromatographic applications  

Energy Technology Data Exchange (ETDEWEB)

The paper presents the results of a study on aryl phases aimed at the increase of the separation selectivity of substances containing {pi} 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.

Gadzal-Kopciuch, R.; Kluska, M.; Welniak, M.; Buszewski, B

2005-02-15

388

Synthesis and antiproliferative evaluation of N,N-disubstituted-N'-[1-aryl-1H-pyrazol-5-yl]-methnimidamides.  

Science.gov (United States)

A series of N,N-disubstituted-N'-[1-aryl-1H-pyrazol-5-yl]-methnimidamides was synthesized by a newly developed microwave reaction and their antiproliferative activities were evaluated. Microwave irradiation of 5-amino-1,3-disubstituted pyrazoles with various amide solvents in the presence of POCl(3) provided the corresponding 2a-2k, 3a-3c, and 4a-4f in good to excellent yields. The obtained methnimidamides were tested against NCI-H661, NPC-TW01, and Jurkat cancer cell lines and the results indicated that compounds 2d and 2e were the most potent with IC(50) values in low micromolar range. PMID:20855206

Cheng, Kaung-Min; Huang, Yu-Ying; Huang, Jiann-Jyh; Kaneko, Kimiyoshi; Kimura, Masayuki; Takayama, Hiroyuki; Juang, Shin-Hun; Wong, Fung Fuh

2010-11-15

389

Synthesis and antitubercular evaluation of novel substituted aryl and thiophenyl tethered dihydro-6H-quinolin-5-ones.  

Science.gov (United States)

A series of novel aryl and thiophenyl tethered dihydro-6H-quinolin-5-ones have been synthesized in very good yields through CeCl(3)·7H(2)O-NaI catalyzed one-pot condensation of ?-enaminones derived from the respective methyl ketones; 1,3-cyclohexanedione & 5,5-dimethyl-1,3-cyclohexanedione and ammonium acetate refluxing in 2-propanol. Dihydro-6H-quinolin-5-ones 3a-f was further derivatized to the respective hydroxymethyl analogs using proline as an organocatalyst in aqueous media. Among the all 18 compounds screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H(37)Rv (MTB), dihydro-6H-quinolin-5-ones 4e and 4f were found to be most active with MIC 3.13 ?g/mL. PMID:21237641

Kantevari, Srinivas; Patpi, Santhosh Reddy; Sridhar, Balasubramanian; Yogeeswari, Perumal; Sriram, Dharmarajan

2011-02-15

390

Ruthenium Catalyzed Decarbonylative Arylation at sp3 Carbon Centers in Pyrrolidine and Piperidine Heterocycles  

Science.gov (United States)

This paper describes the development of a new catalytic transformation, the ruthenium-catalyzed decarbonylative arylation of cyclic 2-amino esters, which replaces the ester group with an aryl ring at the sp3 carbon center. For example, proline ester amidine 1 is converted to 2-arylpyrrolidine 3 in the presence of arylboronic acids or esters as arene donors and Ru3(CO)12 as the catalyst. This process provides a rapid access to a variety of 2-arylpyrrolidines and piperidines from commercially available proline, hydroxyproline, and pipecolinate esters. The examination of the substrate scope also showed that many arene boronic acids and boronate esters serve as coupling partners. The high chemoselectivity of this process was demonstrated and ascribed to the significant rate difference between the decarbonylative arylation and the C–H arylation. The decarbonylative arylation complements the C–H arylation, since the latter process lacks control over the extent of functionalization, affording a mixture of mono- and bis-arylpyrrolidines. When applied in tandem, these two processes provide 2,5-diarylpyrrolidines in two steps from the corresponding proline esters. It was also demonstrated that the required amidine or iminocarbamate directing group fulfills two major functions: first, it is essential for the ester activation step, which occurs via the coordination-assisted metal insertion into the acyl C–O bond; second, it facilitates the decarbonylation, via the stabilization of a metallacycle intermediate, assuring the formation of the 2-arylated products instead of the corresponding ketones observed before by others. PMID:17803274

Gribkov, Denis V.; Pastine, Stefan J.; Schnurch, Michael; Sames, Dalibor

2010-01-01

391

Polymorphism of the aryl-hydrocarbon receptor gene in intron 10 of human cancers  

Directory of Open Access Journals (Sweden)

Full Text Available 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. The 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

2011-11-01

392

Structural investigation of HIV-1 nonnucleoside reverse transcriptase inhibitors: 2-Aryl-substituted benzimidazoles  

Science.gov (United States)

Acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV) is one of the most destructive epidemics in history. Inhibitors of HIV enzymes are the main targets to develop drugs against that disease. Nonnucleoside reverse transcriptase inhibitors of HIV-1 (NNRTIs) are potentially effective and nontoxic. Structural studies provide information necessary to design more active compounds. The crystal structures of four NNRTI derivatives of 2-aryl-substituted N-benzyl-benzimidazole are presented here. Analysis of the geometrical parameters shows that the structures of the investigated inhibitors are rigid. The important geometrical parameter is the dihedral angle between the planes of the ?-electron systems of the benzymidazole and benzyl moieties. The values of these dihedral angles are in a narrow range for all investigated inhibitors. There is no significant difference between the structure of the free inhibitor and the inhibitor in the complex with RT HIV-1. X-ray structures of the investigated inhibitors are a good basis for modeling enzyme-inhibitor interactions in rational drug design.

Zió?kowska, Natasza E.; Michejda, Christopher J.; Bujacz, Grzegorz D.

2009-11-01

393

Spectral and catalytic properties of aryl-alcohol oxidase, a fungal flavoenzyme acting on polyunsaturated alcohols.  

Science.gov (United States)

Spectral and catalytic properties of the flavoenzyme AAO (aryl-alcohol oxidase) from Pleurotus eryngii were investigated using recombinant enzyme. Unlike most flavoprotein oxidases, AAO does not thermodynamically stabilize a flavin semiquinone radical and forms no sulphite adduct. AAO catalyses the oxidative dehydrogenation of a wide range of unsaturated primary alcohols with hydrogen peroxide production. This differentiates the enzyme from VAO (vanillyl-alcohol oxidase), which is specific for phenolic compounds. Moreover, AAO is optimally active in the pH range of 5-6, whereas VAO has an optimum at pH 10. Kinetic studies showed that AAO is most active with p-anisyl alcohol and 2,4-hexadien-1-ol. AAO converts m- and p-chlorinated benzyl alcohols at a similar rate as it does benzyl alcohol, but introduction of a p-methoxy substituent in benzyl alcohol increases the reaction rate approx. 5-fold. AAO also exhibits low activity on aromatic aldehydes. 19F NMR analysis showed that fluorinated benzaldehydes are converted into the corresponding benzoic acids. Inhibition studies revealed that the AAO active site can bind a wide range of aromatic ligands, chavicol (4-allylphenol) and p-anisic (4-methoxybenzoic) acid being the best competitive inhibitors. Uncompetitive inhibition was observed with 4-methoxybenzylamine. The properties described above render AAO a unique oxidase. The possible mechanism of AAO binding and oxidation of substrates is discussed in the light of the results of the inhibition and kinetic studies. PMID:15813702

Ferreira, Patricia; Medina, Milagros; Guillén, Francisco; Martínez, María Jesús; Van Berkel, Willem J H; Martínez, Angel T

2005-08-01

394

Enzymatic aryl-O-methyl-14C labeling of model lignin monomers  

International Nuclear Information System (INIS)

Aryl-O-methyl ethers are abundant in aerobic and anaerobic environments. In particular, lignin is composed of units of this type. Lignin monomers specifically radiolabeled in methoxy, side chain, and ring carbons have been synthesized by chemical procedures and are important in studies of lignin synthesis and degradation, humus formation, and microbial O-demethylation. In this paper attention is drawn to an enzymatic procedure for preparing O-methyl-14C-labeled aromatic lignin monomers which has not previously been exploited in microbial ecology and physiology studies and which has several advantages compared with chemical synthesis procedures. O-[methyl-14C]vanillic and O-[methyl-14C]ferulic acids were prepared with S-[methyl-14C]adenosyl-L-methionine as the methyl donor, using commercially obtained porcine liver catechol-O-methyltransferase (EC 2.1.1.6). The specific activity of the methylated products was the same as that of the methyl donor, a maximum of about 58 ?Ci/?mol, and the yields were 42% (vanillate) and 35% (ferulate). Thus lignin monomers are readily prepared as O-methylated products of the catechol-O-methyltransferase reaction and, with this enzyme method of preparation, would be more widely available than labeled compounds which require chemical synthesis

395

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

Science.gov (United States)

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. PMID:19539383

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

2009-01-01

396

X-ray crystal structure investigation of an N-substituted ciprofloxacin:1-cyclopropyl-6-fluoro-1,4-dihydro-7-[4-(1-isovaleramido- 1-trifluoromethyl-2,2,2-trifluoroethyl)-1-piperazinyl]-4-oxoquinoline- 3-carboxylic acid  

International Nuclear Information System (INIS)

The x-ray crystal and molecular structure of an N-substituted ciprofloxacinC25H27F7N4O4(I) was determined: sp. gr. P21/c; a=9.870(1); b=28.443(3), and c=9.534(1) A; ?=99.09(1) deg., Z=4; and R=0.046 [automated CAD-4 diffractometer,?CuK?; 2687 unique reflections with I?2?]. Molecule I contains a flattened bicyclic 1,4-dihydro-4-oxoquinoline skeleton and a COOH group coplanar to it, which forms a strong intramolecular hydrogen bond with the 4-oxo group. The piperazine ring in I has a chair conformation, and the plane through its four C atoms forms an angle of 37 deg. with the plane through the adjacent benzene ring. Two unusual intramolecular hydrogen bonds are observed in the structure: C(sp3)-H···F-C(ar) and N(sp2)-H···F-C(sp3). In the crystal, molecules I are connected by the intermolecular hydrogen bonds ···O=C-N-H···O=C-N-H···etc., into infinite chains running along the z-axis

397

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

398

Synthesis, in vitro cytotoxicity and apoptosis inducing study of 2-aryl-3-nitro-2H-chromene derivatives as potent anti-breast cancer agents.  

Science.gov (United States)

A series of 2-aryl-3-nitro-2H-chromenes 4a-u were designed as hybrid analogs of flavanone, ?-nitrostyrene and nitrovinylstilbene scaffolds. They were synthesized from the reaction of appropriate ?-nitrostyrenes and salicylaldehydes in good yields. In vitro cytotoxic activities of compounds 4a-u were tested against breast cancer cell lines including MCF-7, T-47D and MDA-MB-231. Most compounds exhibited good cytotoxic activity against selected cell lines, being more potent than standard drug etoposide. Representatively, 8-methoxy-3-nitro-2-(4-chlorophenyl)-2H-chromene (4l) with IC50 = 0.2 ?M against MCF-7 cells, was 36-times more potent than etoposide. Apoptosis as a mechanism of cell death for selected compounds 4h and 4l was confirmed morphologically by acridine orange/ethidium bromide double staining and TUNEL analysis, as well as caspase-3 activation assay. PMID:25216378

Rahmani-Nezhad, Samira; Safavi, Maliheh; Pordeli, Mahboobeh; Ardestani, Sussan Kabudanian; Khosravani, Leila; Pourshojaei, Yaghoub; Mahdavi, Mohammad; Emami, Saeed; Foroumadi, Alireza; Shafiee, Abbas

2014-10-30

399

An efficient one pot syntheses of aryl-3,3'-bis(indolyl)methanes and studies on their spectral characteristics, DPPH radical scavenging-, antimicrobial-, cytotoxicity-, and antituberculosis activity  

Science.gov (United States)

An efficient one-pot syntheses of aryl-3,3'-bis(indolyl)methanes (BIMs) from indole/2-methylindole and formylphenoxyaliphatic acid(s) is described. Esterification of carboxylic acid and aromatic electrophilic substitution reactions are achieved simultaneous in the presence of potash alum as a catalyst. This catalyst could be recovered and reused without substantial loss in its catalytic activity and the methodology could be applied on a range of closely related substrates. The solvation characteristics in ground and excited states of the compounds by monitoring the absorbance and fluorescence band maxima have been studied. The fluorescence studies in protic and aprotic solvents were rationalized on the basis of solute-solvent interaction and substituents effect on these photophysical processes analyzed. The compounds prepared showed efficient antimicrobial effect against human pathogens, cytotoxicity against A431 cell line, and DPPH radical scavenging effect. Single crystal XRD studies have been carried out for a few compounds synthesized in this work.

Suresh Kumar, G. S.; Kumaresan, S.; Antony Muthu Prabhu, A.; Bhuvanesh, N.; Seethalakshmi, P. G.

2013-01-01

400

Asymmetric Contribution of Aromatic Interactions Stems from Spatial Positioning of the Interacting Aryl Pairs in ?-Hairpins.  

Science.gov (United States)

Isolated aromatic interactions in designed octapeptide ?-hairpin scaffolds display a near-universal T-shaped face-to-edge geometry in all positional permutations, with the exception of aryl-Trp interactions. The heterogeneous asymmetric indole ring of Trp competes for a "shielding" face geometry, which lowers the scaffold stability in FtE aryl-Trp pairs. Assessment of the contributions of aryl pairs (in the absence of solvent-driven interactions) to the overall ?-hairpin structure reveals the superiority of Trp-Phe and Trp-Tyr contributions over the well-established scaffold stabilization by Trp-Trp. PMID:25196944

Makwana, Kamlesh Madhusudan; Mahalakshmi, Radhakrishnan

2014-11-01

 
 
 
 
401

1,3-Halogen migration as an entry to aryl coppers from an unintuitive starting material.  

Science.gov (United States)

A copper(I) catalyzed 1,3-halogen migration/borylation migrates a bromine from an sp(2) carbon to a benzylic carbon with concomitant borylation of the aryl-bromine bond. This transformation proceeds via an aryl copper intermediate which can be accessed independently and then trapped with electrophiles. As such, copper-catalyzed 1,3-halogen migration provides unique and mild access to an aryl copper species that allows for rapid aromatic functionalization from an unconventional starting material. PMID:25136932

Van Hoveln, R J; Schmid, S C; Schomaker, J M

2014-10-21

402

Manganese(IV)-mediated hydroperoxyarylation of alkenes with aryl hydrazines and dioxygen from air.  

Science.gov (United States)

We report a new carbooxygenation-type version of the Meerwein arylation in which the introduction of oxygen is achieved by using dioxygen from the air. In this way, hydroperoxides were obtained from activated as well as non-activated alkenes by oxidizing aryl hydrazines with manganese dioxide. The best results were obtained with ?-substituted acrylates. Importantly, the aryl hydrazine has to be added slowly to the reaction mixture to allow sufficient uptake of dioxygen from the air. Competition and labeling experiments revealed hydroperoxyl radicals as novel oxygen-centered radical scavengers. PMID:24737215

Kindt, Stephanie; Jasch, Hannelore; Heinrich, Markus R

2014-05-19

403

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

404

Application of metalation reactions for synthesis of sulfur/selenium-containing heterocyclic compounds  

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This thesis deals mainly with the synthesis of various sulfur/selenium-containing heterocyclic compounds, many of which include structural features present in several biologically active molecules, with particular emphasis on compounds of synthetic importance, such as indoles, as well as other heteroaromatic species. In the first part, an efficient procedure toward synthesis of new 3-(arylthio)indoles based on reactions of aryl Grignard reagents or lithiated heteroaromat...

Shirani, Hamid

2009-01-01

405

Intercalated organic-inorganic perovskites stabilized by fluoroaryl-aryl interactions.  

Science.gov (United States)

Crystals of several new hybrid tin(II) iodide-based perovskites, involving 2,3,4,5,6- pentafluorophenethylammonium or phenethylammonium cation bilayers and intercalated aryl or perfluoroaryl molecules, were grown by slow evaporation of a methanol solution containing the hybrid perovskite and the intercalating species. The (C(6)F(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)H(6)) structure was solved at -75 degrees C in a monoclinic C2/c subcell [a = 41.089(12) A, b = 6.134(2) A, c = 12.245(3) A, beta = 94.021(5) degrees, Z = 4] and consists of sheets of corner-sharing distorted SnI(6) octahedra separated by bilayers of pentafluorophenethylammonium cations. The intercalated benzene molecules form a single well-ordered layer interposed between adjacent fluoroaryl cation layers. The corresponding hybrid with an unfluorinated organic cation and fluorinated intercalating molecule, (C(6)H(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)F(6)), is isostructural [a = 40.685(4) A, b = 6.0804(6) A, c = 12.163(1) A, beta = 93.136(2) degrees, Z = 4]. For each intercalated system, close C...C contacts (3.44-3.50 A) between the aromatic cation and the intercalated molecule are indicative of a significant face-to-face interaction, similar to that found in the complex C(6)H(6).C(6)F(6). Crystal growth runs with the organic cation and prospective intercalating molecule either both fluorinated or both unfluorinated did not yield stable intercalated compounds, demonstrating the significance of fluoroaryl-aryl interactions in the current intercalated structures. Thermal analysis of (C(6)F(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)H(6)) and (C(6)H(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)F(6)) crystals yields, in addition to the characteristic transitions of the parent perovskite, endothermic transitions [12.6(5) and 32.1(8) kJ/mol, respectively] with an onset at 145 degrees C and a weight loss corresponding to the complete loss of the intercalated molecule. The relatively high deintercalation temperature (well above the boiling point of benzene and hexafluorobenzene) demonstrates the usefulness of the hybrid perovskites in providing a stable framework for the examination of the fluoroaryl-aryl interaction, as well as the potential importance of this interaction in tailoring new hybrid perovskites. UV-vis absorption measurements on (C(6)H(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)F(6)) thin films indicate a small reversible wavelength shift to higher energy for the tin(II) iodide framework exciton peak (with respect to that of the parent perovskite spectrum), from 608(2) nm [2.04 eV] to 595(2) nm [2.08 eV], and a corresponding shift in the band edge position. This spectral shift can most reasonably be attributed to subtle structural changes induced in the tin(II) iodide sheets by the intercalated hexafluorobenzene molecules. PMID:11952366

Mitzi, David B; Medeiros, David R; Malenfant, Patrick R L

2002-04-22

406

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

407

Synthesis and conformational study of some r(2), c(4)-bis(isopropoxycarbonyl)- t(3)-aryl- c(5)-hydroxy- t(5)-methylcyclohexanones using NMR spectra  

Science.gov (United States)

Seven r(2), c(4)-bis(isopropoxycarbonyl)- t(3)-aryl- c(5)-hydroxy- t(5)-methylcyclohexanones 7- 13 (aryl = C 6H 5, p-ClC 6H 4, p-FC 6H 4, p-OMeC 6H 4, p-Me 2NC 6H 4, m-O 2NC 6H 4 and m-C 6H 5OC 6H 4) have been synthesized by condensing isopropyl acetoacetate with aromatic aldehydes in the presence of methylamine. For all these compounds 1H and 13C NMR spectra have been recorded. For 7, HOMOCOSY, NOESY, HSQC and HMBC spectra also have been recorded. The spectral data suggest that compounds 7- 13 exist in chair conformation with axial orientation of the hydroxy group and equatorial orientations of all the other substituents. Long range coupling is observed between OH proton and H(6a) in all cases suggesting that OH group is anti to C(5) sbnd C(6) bond. In all cases four distinct doublets are observed for the methyl protons of the two isopropyl groups. In 7 and 13 four separate, closely spaced signals are observed for the methyl carbons of the two isopropyl groups. All signals could be assigned unambiguously in the case of 7. The protons of one methyl group of the isopropoxycarbonyl group at C-4 seems to be highly shielded. This suggests that these protons lie above the plane of the aryl group at C(3). This conclusion is in accordance with the structure of 7, determined by X-ray crystallography. MOPAC calculations on 7 suggest that the chair conformation with OH group anti to C(5) sbnd C(6) bond is more stable than the chair conformation with OH bond anti to C(5) sbnd CH 3 bond by 1.5 kcal mol -1.

Pandiarajan, K.; Mohan, R. T. Sabapathy; Murugavel, K.; Hema, R.

2008-03-01

408

Aromatic fluorine compounds. VI. Displacement of aryl fluorine in diazonium salts  

Science.gov (United States)

Several chlorofluorobenzenes have been isolated from the Schiemann synthesis of fluorobenzenes. These have been shown to be the products of two side reactions occurring during thermal decomposition of the dry benzenediazonium fluoborate salt containing coprecipitated sodium chloride, an unavoidable contaminant in large preparations involving the use of hydrochloric acid and sodium fluoborate. The major side reaction and its chloro product were unexpected; a unique displacement of fluorine ortho to the diazonium group was observed. Replacement of the diazo group with chlorine was the predicted side reaction which proved to be minor. Conditions causing the side reactions and the isolation and identification of the products are described.

Finger, G. C.; Oesterling, R. E.

1956-01-01

409

Substituted polychlorinated dibenzofuran receptor binding affinities and aryl hydrocarbon hydroxylase induction potencies--a QSAR analysis.  

Science.gov (United States)

The rat hepatic cytosolic receptor binding affinities of 8-substituted 2,3-dichlorodibenzofurans and 8-substituted 2,3,4-trichlorodibenzofurans have been measured. The EC50-value for each compound was determined by dose-response competitive displacement of 2,3,7,8-[3H] tetrachlorodibenzo-p-dioxin (TCDD). Multiple parameter linear regression analysis of the data using several substituent parameters [lipophilicity (pi), hydrogen bonding (HB), electronegativity (sigma op), STERIMOL (delta B5)] demonstrated that for both sets of ligands, the binding affinities were dependent on substituent pi-values. The equations derived for the 8-substituted 2,3,4-trichlorodibenzofurans (a) and 8-substituted 2,3-dichlorodibenzofurans (b) were (Formula: see text) remarkably similar, moreover the relatively bulky t-butyl substituent was treated as an outlier for both calculations. The in vitro induction of aryl hydrocarbon hydroxylase (AHH) and ethoxyresorufin O-deethylase (EROD) in rat hepatoma H-4-II E cells by both sets of ligands demonstrated that there was not a rank order correlation between induction potencies and receptor binding affinities for these compounds. Analysis of the data for the 8-substituted 2,3-dichlorodibenofurans demonstrated that the monooxygenase enzyme induction was dependent on substituent lipophilicity and a STERIMOL (delta B5) factor which is related to (Formula: see text) substituent width. In contrast, the equation for the 8-substituted 2,3,4-trichlorodibenzofurans also included a substituent sigma op Hammett constant. The results indicate that although the binding affinities of the two sets of ligands are dependent only on substituent pi-values, their enzyme induction activities are both substituent and chlorine substitution pattern-dependent. PMID:3006935

Denomme, M A; Homonko, K; Fujita, T; Sawyer, T; Safe, S

1986-02-01

410

Organ specificity of aryl hydrocarbon hydroxylase induction by cigarette smoke  

Energy Technology Data Exchange (ETDEWEB)

Biotransformation of many chemicals found in cigarette smoke, such as PAHs and nitrosamines, is generally considered essential for the mutagenic, carcinogenic effects of these xenobiotics. In fact, the genotic action of these premutagens or precarcinogens is dependent on metabolic activation catalyzed by microsomal monooxygenases. The first enzymatic reaction of the PAHs metabolic pathway is catalyzed by a cytochrome P-450-dependent monooxygenase, the aryl hydrocarbon hydroxylase (AHH). AHH leads to the formation of reactive arene oxides, which are further metabolized by enzymatic and non-enzymatic reaction into many metabolites. AHH induction in laboratory animals exposed to cigarette smoke has also been reported, and the data show that this response is highly dependent on species and tissues. Exposure of small laboratory animals to cigarette smoke generally induces AHH in the kidney and lung, while the effect of cigarette smoke on the hepatic AHH activity appears variable.

Yoshikawa, M.; Arashidani, K.; Kawamoto, T.; Kodama, Y. (Univ. of Occupational and Environmental Health, Fukuoka (Japan))

1990-06-01

411

Aryl hydrocarbon receptor ligands in cancer: friend and foe.  

Science.gov (United States)

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that is best known for mediating the toxicity and tumour-promoting properties of the carcinogen 2,3,7,8-tetrachlorodibenzo-p-dioxin, commonly referred to as 'dioxin'. AHR influences the major stages of tumorigenesis - initiation, promotion, progression and metastasis - and physiologically relevant AHR ligands are often formed during disease states or during heightened innate and adaptive immune responses. Interestingly, ligand specificity and affinity vary between rodents and humans. Studies of aggressive tumours and tumour cell lines show increased levels of AHR and constitutive localization of this receptor in the nucleus. This suggests that the AHR is chronically activated in tumours, thus facilitating tumour progression. This Review discusses the role of AHR in tumorigenesis and the potential for therapeutic modulation of its activity in tumours. PMID:25417591

Murray, Iain A; Patterson, Andrew D; Perdew, Gary H

2014-11-24

412

The aryl hydrocarbon receptor: multitasking in the immune system.  

Science.gov (United States)

The aryl hydrocarbon receptor (AhR), for many years almost exclusively studied by the pharmacology/toxicology field for its role in mediating the toxicity of xenobiotics such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), has more recently attracted the attention of immunologists. The evolutionary conservation of this transcription factor and its widespread expression in the immune system point to important physiological functions that are slowly being unraveled. In particular, the emphasis is now shifting from the role of AhR in the xenobiotic pathway toward its mode of action in response to physiological ligands. In this article, we review the current understanding of the molecular interactions and functions of AhR in the immune system in steady state and in the presence of infection and inflammation, with a focus on barrier organs such as the skin, the gut, and the lung. PMID:24655296

Stockinger, Brigitta; Di Meglio, Paola; Gialitakis, Manolis; Duarte, João H

2014-01-01

413

A general method for palladium-catalyzed reactions of primary sulfonamides with aryl nonaflates.  

Science.gov (United States)

A general method for Pd-catalyzed sulfonamidation of aryl nonafluorobutanesulfonates (aryl nonaflates) is described. A biaryl phosphine ligand, t-BuXPhos, formed the most active catalyst, and K(3)PO(4) in tert-amyl alcohol was found to be the optimal base-solvent combination for the reaction. The reaction conditions were tolerant of various functional groups such as cyano, nitro, ester, aldehyde, ketone, chloride, carbamate, and phenol. Heterocyclic aryl nonaflates were found to be suitable coupling partners. High yields of the coupled products were obtained from the reactions between inherently disfavored substrates such as electron-rich nonaflates and electron-poor sulfonamides. Kinetic data suggest reductive elimination to be the rate-limiting step for the reaction. The only limitation of this methodology that we have identified is the inability of 2,6-disubstituted aryl nonaflates to efficiently participate in the reaction. PMID:21510695

Shekhar, Shashank; Dunn, Travis B; Kotecki, Brian J; Montavon, Donna K; Cullen, Steven C

2011-06-01

414

Late-stage diversification of peptides by metal-free c?h arylation.  

Science.gov (United States)

The bioorthogonal late-stage diversification of functionalized oligopeptides was accomplished through a metal-free, site-selective C?H arylation of engineered indole derivatives under mild reaction conditions. PMID:25168602

Zhu, Yingjun; Bauer, Michaela; Ploog, Jasper; Ackermann, Lutz

2014-10-01

415

Bulky alkylphosphines with neopentyl substituents as ligands in the amination of aryl bromides and chlorides.  

Science.gov (United States)

Di(tert-butyl)neopentylphosphine (DTBNpP) in combination with palladium sources provided catalysts with comparable or better activity for the Hartwig-Buchwald amination of aryl bromides than tri(tert-butyl)phosphine (TTBP) under mild conditions. DTBNpP also provided effective catalysts for amination reactions of aryl chlorides at elevated temperatures. Further replacement of tert-butyl groups with neopentyl substituents resulted in less effective ligands for amination reactions. Computationally derived cone angles showed that replacement of a tert-butyl group with a neopentyl group significantly increased the cone angle of the phosphine. The larger cone angle of DTBNpP than TTBP appears to correlate with the higher activity of catalysts derived from DTBNpP in the amination of aryl bromides. TTBP is a stronger electron donor than DTBNpP, which may explain the higher activity for TTBP-derived catalysts toward aryl chlorides. PMID:16808497

Hill, Lensey L; Moore, Lucas R; Huang, Rongcai; Craciun, Raluca; Vincent, Andrew J; Dixon, David A; Chou, Joe; Woltermann, Christopher J; Shaughnessy, Kevin H

2006-07-01

416

Design, synthesis and pharmacological screening of a series of N1-(substituted) aryl-5,7-dimethyl-2-(substituted)pyrido(2,3-d)-pyrimidin-4(3H)-ones as potential histamine H1-receptor antagonists.  

Science.gov (United States)

A series of N1-(substituted)aryl-5,7-dimethyl-2-(substituted)pyrido(2,3-d)pyrimidin-4(3H)-one was designed on the basis of the triangular pharmacophoric requirement of histamine H1-receptor antagonists. The designed series was synthesized by cyclo-condensation of monoaryl thiourea with ethyl cyanoacetate in the presence of dry HCl gas to give N1-(substituted aryl)-2-mercaptopyrimidine-4(3H)-one, which on cyclo-condensation with acetylacetone gave the pyridopyrimidinone. Further methylation of the mercapto group at C-2 with methyl iodide followed by nucleophilic displacement of the methylmercapto group by various amines gave the targeted compounds. All the synthesized compounds were screened for histamine H1-receptor antagonistic activity by the in vitro method of inhibition of the isotonic contraction induced by histamine on isolated guinea pig ileum using cetirizine as a standard drug. All the compounds exhibited potent histamine H1-receptor antagonistic activity with pA2 values from 7.30- 9.75 (cetirizine, pA2 value 9.40). The potent compounds were screened for their in vivo antihistaminic activity by protection of animal from asphyxic shock. The sedative potential of potent compounds was checked on albino mice by photoactometer and they had comparative sedative potential to the standard drug cetirizine. None of the compound exhibited anticholinergic activity in the in vitro rat ileum model. PMID:17252940

Suhagia, Bhanubhai N; Chhabria, Mahesh T; Makwana, Ashlesha G

2006-12-01

417

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

418

Regiospecific One-Pot Synthesis of Diaryliodonium Tetrafluoroborates from Arylboronic Acids and Aryl Iodides  

DEFF Research Database (Denmark)

Abstract: Diaryliodonium salts have recently received considerable attention as mild arylation reagents in organic synthesis. This paper describes a regiospecific, sequential one-pot synthesis of symmetrical and unsymmetrical diaryliodonium tetrafluoroborates, which are the most popular salts in metal-catalyzed arylations. The protocol is fast and high-yielding and has a large substrate scope. Furthermore, the corresponding diaryliodonium triflates can conveniently be obtained via an in situ anion exchange.

Bielawski, Marcin; Aili, David

2008-01-01

419

Novel copper-catalyzed multicomponent cascade synthesis of iminocoumarin aryl methyl ethers.  

Science.gov (United States)

A copper(I)-catalyzed one-pot synthesis of iminocoumarin aryl methyl ethers has been developed from ynal, phenol, and sulfonyl azide at ambient conditions via a cascade [3 + 2]-cycloaddition, 1,3-pseudopericyclic ketenimine rearrangement, 1,4-conjugate addition, and aldol-type condensation. This protocol provides a potential route for the construction of a library of iminocoumarin aryl methyl ethers in good yields. PMID:23875790

Murugavel, Govindarasu; Punniyamurthy, Tharmalingam

2013-08-01

420

Synthesis of ?-Peroxyesters via Organocatalyzed O-H Insertion of Hydroperoxides and Aryl Diazoesters.  

Science.gov (United States)

The synthesis of ?-aryl peroxyesters, an unprecedented class of organic peroxide, via hydrogen-bond donor catalyzed O-H insertions of hydroperoxides and ?-aryl diazoesters is reported. The method is applicable to a diverse set of substrates and the corresponding ?-peroxyesters are typically isolated in high yield. Both thermogravimetric analysis and reactions with traditional peroxide reducing agents demonstrate the stability of ?-peroxyesters. PMID:25265196

Fisher, Thomas J; Mattson, Anita E

2014-10-17

 
 
 
 
421

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

422

Tetrabutylammonium 2-pyridyltriolborate salts for Suzuki-Miyaura cross-coupling reactions with aryl chlorides.  

Science.gov (United States)

Palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of tetrabutylammonium 2-pyridyltriolborate salts with various aryl (heteroaryl) chlorides can produce the corresponding desired coupling products with good to excellent yields. These tetrabutylammonium salts are more reactive than the corresponding lithium salts. The coupling reactions with aryl chlorides progressed in the presence of PdCl2dcpp (3 mol %) and CuI/MeNHCH2CH2OH (20 mol %) in anhydrous DMF without bases. PMID:23952320

Sakashita, Shohei; Takizawa, Miho; Sugai, Juugaku; Ito, Hajime; Yamamoto, Yasunori

2013-09-01

423

Synthesis of boron-substituted diaryliodonium salts and selective transformation into functionalized aryl boronates.  

Science.gov (United States)

Dormant boron awaits its true destiny in diaryliodonium salts synthesized from aryl boronate derivatives according to two alternative general methods with hypervalent iodine(III) reagents and fluoroalcohol solvents: transformation of an aryl C-H bond and boron-iodine(III) exchange (see scheme; FG = functional group). The salts could be functionalized by both catalyst-free and metal-catalyzed reactions without loss of the boron functionality. PMID:23139190

Ito, Motoki; Itani, Itsuki; Toyoda, Yosuke; Morimoto, Koji; Dohi, Toshifumi; Kita, Yasuyuki

2012-12-01

424

Non-thiol farnesyltransferase inhibitors: utilization of an aryl binding site by 5-arylacryloylaminobenzophenones.  

Science.gov (United States)

We recently described a novel aryl binding site of farnesyltransferase. The 2-naphthylacryloyl residue was developed as an appropriate substituent for our benzophenone-based AAX-peptidomimetic capable of occupying this binding site, resulting in a non-thiol farnesyltransferase inhibitor with nanomolar activity. The activity of this inhibitor is readily explained on the basis of docking studies which show the 2-naphthyl residue fitting into the aryl binding site. PMID:12057654

Mitsch, Andreas; Böhm, Markus; Wissner, Pia; Sattler, Isabel; Schlitzer, Martin

2002-08-01

425

Mild hypervalent iodine mediated oxidative nitration of N-aryl sulfonamides.  

Science.gov (United States)

An oxidative and acid-free method for the nitration of N-aryl sulfonamides has been developed using a combination of sodium nitrite as cheap and easy to handle NO2-source and the hypervalent iodine reagent PIFA as stoichiometric oxidant. Under very mild reaction conditions, the desired mononitrated aryl sulfonamides were isolated in up to 87% yield. This is the first example of an iodane-mediated oxidative nitration. PMID:25068377

Kloeckner, Ulrich; Nachtsheim, Boris J

2014-09-18

426

Copper-catalyzed [18F]fluorination of (mesityl)(aryl)iodonium salts.  

Science.gov (United States)

A practical, rapid, and highly regioselective Cu-catalyzed radiofluorination of (mesityl)(aryl)iodonium salts is described. This protocol utilizes [(18)F]KF to access (18)F-labeled electron-rich, -neutral, and -deficient aryl fluorides under a single set of mild conditions. This methodology is applied to the synthesis of protected versions of two important radiotracers: 4-[(18)F]fluorophenylalanine and 6-[(18)F]fluoroDOPA. PMID:24890658

Ichiishi, Naoko; Brooks, Allen F; Topczewski, Joseph J; Rodnick, Melissa E; Sanford, Melanie S; Scott, Peter J H

2014-06-20