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Suchetha N Shetty - One of the best experts on this subject based on the ideXlab platform.
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synthesis and antimicrobial activities of some novel 1 2 4 triazolo 3 4 b 1 3 4 thiadiazoles and 1 2 4 triazolo 3 4 b 1 3 4 thiadiazines carrying thioalkyl and sulphonyl phenoxy moieties
European Journal of Medicinal Chemistry, 2007Co-Authors: T Karabasanagouda, Airody Vasudeva Adhikari, Suchetha N ShettyAbstract:Abstract Thirty one new 6-aryl-3-{(4-substituted phenoxy) methyl}-1,2,4-triazolo[3,4- b ]-1,3,4-thiadiazoles ( 6a – s ) and 6-aryl-3-{(4-substituted phenoxy methyl}-7 H -1,2,4-triazolo[3,4- b ]-1,3,4-thiadiazines ( 7a – l ) have been synthesized from 4-thioalkyl phenols ( 1a – b ) through a multi-step reaction sequence. Compounds 1a – b reacted with ethyl chloroacetate in presence of acetone and potassium carbonate to give ethyl [4-(thioalkyl) phenoxy] acetates ( 2a – b ). Further, 2a was oxidized to [4-(methyl sulphonyl) phenoxy] acetate ( 2c ) using hydrogen peroxide in acetic acid. Reactions of ( 2a – c ) with hydrazine hydrate in alcoholic medium furnished 2-[4-thiosubstituted phenoxy] acetohydrazides ( 3a – b ) and 2-[4-methyl sulphonyl phenoxy] acetohydrazide ( 3c ) which on treatment with carbon disulphide and methanolic potassium hydroxide yielded corresponding potassium dithiocarbazates ( 4a – c ). They were then converted to 4-amino-5-{(4-thioalkyl phenoxy) methyl}-4 H -1,2,4-triazole-3-thiols ( 5a – b ) and 4-amino-5-{(4-methyl sulphonyl phenoxy) methyl}-4 H -1,2,4-triazole-3-thiol ( 5c ) by refluxing them with aqueous hydrazine hydrate. The title compounds 6a – s were prepared by condensing 5a – c with various aromatic carboxylic acids in presence of phosphorus oxychloride. The intermediates 5a – c , on condensation with various substituted phenacyl bromides afforded a series of title compounds ( 7a – l ). The structures of new compounds 2a – 7l were established on the basis of their elemental analysis, IR, 1 H NMR, 13 C NMR and mass spectral data. All the title compounds were subjected to in vitro antibacterial testing against four pathogenic strains and antifungal screening against three fungi. Preliminary results indicate that some of them exhibited promising activities and they deserve more consideration as potential antimicrobials.
T Karabasanagouda - One of the best experts on this subject based on the ideXlab platform.
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synthesis and antimicrobial activities of some novel 1 2 4 triazolo 3 4 b 1 3 4 thiadiazoles and 1 2 4 triazolo 3 4 b 1 3 4 thiadiazines carrying thioalkyl and sulphonyl phenoxy moieties
European Journal of Medicinal Chemistry, 2007Co-Authors: T Karabasanagouda, Airody Vasudeva Adhikari, Suchetha N ShettyAbstract:Abstract Thirty one new 6-aryl-3-{(4-substituted phenoxy) methyl}-1,2,4-triazolo[3,4- b ]-1,3,4-thiadiazoles ( 6a – s ) and 6-aryl-3-{(4-substituted phenoxy methyl}-7 H -1,2,4-triazolo[3,4- b ]-1,3,4-thiadiazines ( 7a – l ) have been synthesized from 4-thioalkyl phenols ( 1a – b ) through a multi-step reaction sequence. Compounds 1a – b reacted with ethyl chloroacetate in presence of acetone and potassium carbonate to give ethyl [4-(thioalkyl) phenoxy] acetates ( 2a – b ). Further, 2a was oxidized to [4-(methyl sulphonyl) phenoxy] acetate ( 2c ) using hydrogen peroxide in acetic acid. Reactions of ( 2a – c ) with hydrazine hydrate in alcoholic medium furnished 2-[4-thiosubstituted phenoxy] acetohydrazides ( 3a – b ) and 2-[4-methyl sulphonyl phenoxy] acetohydrazide ( 3c ) which on treatment with carbon disulphide and methanolic potassium hydroxide yielded corresponding potassium dithiocarbazates ( 4a – c ). They were then converted to 4-amino-5-{(4-thioalkyl phenoxy) methyl}-4 H -1,2,4-triazole-3-thiols ( 5a – b ) and 4-amino-5-{(4-methyl sulphonyl phenoxy) methyl}-4 H -1,2,4-triazole-3-thiol ( 5c ) by refluxing them with aqueous hydrazine hydrate. The title compounds 6a – s were prepared by condensing 5a – c with various aromatic carboxylic acids in presence of phosphorus oxychloride. The intermediates 5a – c , on condensation with various substituted phenacyl bromides afforded a series of title compounds ( 7a – l ). The structures of new compounds 2a – 7l were established on the basis of their elemental analysis, IR, 1 H NMR, 13 C NMR and mass spectral data. All the title compounds were subjected to in vitro antibacterial testing against four pathogenic strains and antifungal screening against three fungi. Preliminary results indicate that some of them exhibited promising activities and they deserve more consideration as potential antimicrobials.
Airody Vasudeva Adhikari - One of the best experts on this subject based on the ideXlab platform.
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synthesis and antimicrobial activities of some novel 1 2 4 triazolo 3 4 b 1 3 4 thiadiazoles and 1 2 4 triazolo 3 4 b 1 3 4 thiadiazines carrying thioalkyl and sulphonyl phenoxy moieties
European Journal of Medicinal Chemistry, 2007Co-Authors: T Karabasanagouda, Airody Vasudeva Adhikari, Suchetha N ShettyAbstract:Abstract Thirty one new 6-aryl-3-{(4-substituted phenoxy) methyl}-1,2,4-triazolo[3,4- b ]-1,3,4-thiadiazoles ( 6a – s ) and 6-aryl-3-{(4-substituted phenoxy methyl}-7 H -1,2,4-triazolo[3,4- b ]-1,3,4-thiadiazines ( 7a – l ) have been synthesized from 4-thioalkyl phenols ( 1a – b ) through a multi-step reaction sequence. Compounds 1a – b reacted with ethyl chloroacetate in presence of acetone and potassium carbonate to give ethyl [4-(thioalkyl) phenoxy] acetates ( 2a – b ). Further, 2a was oxidized to [4-(methyl sulphonyl) phenoxy] acetate ( 2c ) using hydrogen peroxide in acetic acid. Reactions of ( 2a – c ) with hydrazine hydrate in alcoholic medium furnished 2-[4-thiosubstituted phenoxy] acetohydrazides ( 3a – b ) and 2-[4-methyl sulphonyl phenoxy] acetohydrazide ( 3c ) which on treatment with carbon disulphide and methanolic potassium hydroxide yielded corresponding potassium dithiocarbazates ( 4a – c ). They were then converted to 4-amino-5-{(4-thioalkyl phenoxy) methyl}-4 H -1,2,4-triazole-3-thiols ( 5a – b ) and 4-amino-5-{(4-methyl sulphonyl phenoxy) methyl}-4 H -1,2,4-triazole-3-thiol ( 5c ) by refluxing them with aqueous hydrazine hydrate. The title compounds 6a – s were prepared by condensing 5a – c with various aromatic carboxylic acids in presence of phosphorus oxychloride. The intermediates 5a – c , on condensation with various substituted phenacyl bromides afforded a series of title compounds ( 7a – l ). The structures of new compounds 2a – 7l were established on the basis of their elemental analysis, IR, 1 H NMR, 13 C NMR and mass spectral data. All the title compounds were subjected to in vitro antibacterial testing against four pathogenic strains and antifungal screening against three fungi. Preliminary results indicate that some of them exhibited promising activities and they deserve more consideration as potential antimicrobials.
Dilip D. Dhavale - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and Conformational Study of Chiral Oxepines: The Baylis−Hillman Reaction and RCM Approach with Sugar Aldehyde
Journal of Organic Chemistry, 2009Co-Authors: Vrushali H Jadhav, Rahul V Pinjari, Shridhar P Gejji, Omprakash P Bande, Vedavati G. Puranik, Dilip D. DhavaleAbstract:The Baylis−Hillman reaction of 3-O-allyl-α-d-xylo-pentodialdo-1,4-furanose 3 afforded a diastereomeric mixture of d-gluco- and l-ido-configured α-methylene-β-hydroxy esters 4a and 4b, respectively, in a ratio of 2:3. Reduction of the ester functionality in 4a/4b gave alcohols 5a/5b. The diene thus formed in 5a/5b was subjected to ring-closing metathesis (Grubbs' second-generation catalyst) to afford oXA-bicyclic ring system 6a/6b in high yield. Further manipulation of the acetonide functionality in 6a and 6b afforded new polyhydroxylated oxepines 1a/2a and 1b/2b, respectively. The 1H NMR of oxepines 1a and 1b in D2O showed doubling of signals indicating their existence in two different rotamers/conformers. This fact was substantiated by calculating energetics of 1 and 2 conformers using the density functional theory and correlating the calculated 1H NMR chemical shift pattern with that of the experimental spectra.
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synthesis and conformational study of chiral oxepines the baylis hillman reaction and rcm approach with sugar aldehyde
Journal of Organic Chemistry, 2009Co-Authors: Vrushali H Jadhav, Rahul V Pinjari, Shridhar P Gejji, Omprakash P Bande, Vedavati G. Puranik, Dilip D. DhavaleAbstract:The Baylis−Hillman reaction of 3-O-allyl-α-d-xylo-pentodialdo-1,4-furanose 3 afforded a diastereomeric mixture of d-gluco- and l-ido-configured α-methylene-β-hydroxy esters 4a and 4b, respectively, in a ratio of 2:3. Reduction of the ester functionality in 4a/4b gave alcohols 5a/5b. The diene thus formed in 5a/5b was subjected to ring-closing metathesis (Grubbs' second-generation catalyst) to afford oXA-bicyclic ring system 6a/6b in high yield. Further manipulation of the acetonide functionality in 6a and 6b afforded new polyhydroxylated oxepines 1a/2a and 1b/2b, respectively. The 1H NMR of oxepines 1a and 1b in D2O showed doubling of signals indicating their existence in two different rotamers/conformers. This fact was substantiated by calculating energetics of 1 and 2 conformers using the density functional theory and correlating the calculated 1H NMR chemical shift pattern with that of the experimental spectra.
V. V. Mulwad - One of the best experts on this subject based on the ideXlab platform.
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synthesis and antimicrobial screening of 5 h 7 h n coumarin 6 yl 2 8 diphenyl 5 7 dioxo 4 5 6 7 tetrahydrobenzimidazo 5 6 c furan and 5 h 7 h n coumarin 6 yl 2 8 diphenyl 5 7 dioxo 6 7 methoxy 4 methylcoumarin 6 yl 4 5 6 7 tetrahydro benzimidazo 5 6
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2006Co-Authors: B. P. Choudhari, V. V. MulwadAbstract:The Schiff bases 2a-d of 6-aminocoumarins 1a-d on reaction with 4-benzylidene-2-phenyloXAzolin-5-one in DMF and catalytic amount of pyridine afford 4-benzylidene-3-(coumarin-6-yl)-2-phenylimidazolin-5-ones 3a-d which on further Wittig reaction yield the corresponding 4-benzylidene-3-(coumarin-6-yl)-5-methylene-2-phenylimidazolines 4a-d. Compounds 4a-d on Diel's-Alder reaction with maleic anhydride and N-(7-methoxy-4-methylcoumarin-6-yl)maleimide separately give 5H,7H-N-(coumarin-6-yl)-2,8-diphenyl-5,7-dioxo-4,5,6,7-tetrahydrobenzimidazo(5,6-c)furans 5a-d and 5H,7H-N-(coumarin-6-yl)-2,8-diphenyl-5,7-dioxo-6-(7-methoxy-4-methylcoumarin-6-yl)-4,5,6,7-tetrahydrobenzimidazo(5,6-c)pyrroles 6a-d respectively. The structures of the compounds have been established on the basis of the spectral and analytical data. All the compounds 3-6a-d have been screened for their antimicrobial activities and found to exhibit significant antibacterial and antifungal activities.
