Prof. Manas Chakrabarty
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Recent Submissions
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An expedient, regioselective synthesis of 2-alkylamino- and 2-alkylthiothiazolo[5,4-e]indoles
(PERGAMON-ELSEVIER SCIENCE LTD, 2005-04-18)1-Benzenesulfonyl-5-aminoindole 5, prepared from 5-nitroindole 3, was condensed with alkyl isothiocyanates and separately with carbon disulfide and alkyl bromides/iodides to furnish efficiently the corresponding ... -
A new catalytic application of a keggin acid in the synthesis of symmetrical bis(indolyl)alkanes
(PERGAMON-ELSEVIER SCIENCE LTD, 2006-02-01)Silicotungstic acid, H4SiW12O40, an important Keggin heteropoly acid, efficiently catalysed the reaction of indoles with aryl aldehydes in ethyl acetate solution at room temperature to furnish symmetrical bis(indolyl)alkanes ... -
A facile clay-mediated synthesis of 3,3-diindolyl-2-indolinones from isatins
(SCIENCE REVIEWS LTD, 2005-08-01)Dry reaction of isatins (3a, 3b) with indoles (4a-e) on montmorillonite K10 clay at room temperature furnished within minutes 3,3-bis(3'-indolyl)-2-indolinones (1a-f) in high yields. 5-Nitroisatin (3c) furnished, in addition ... -
A novel, expedient synthesis of thiazolo[4,5-c]- and -[5,4-b]carbazoles
(PERGAMON-ELSEVIER SCIENCE LTD, 2004-01-01)A new synthesis of thiazolo[4,5-c]- and -[5,4-b]carbazoles (6a-e, 7a, 8b-e) was accomplished from 3-aminocarbazoles (3a-e) by separate condensations with methyl and phenyl isothiocyanates, followed by oxidative cyclization ... -
A new catalytic application of a keggin acid in the synthesis of symmetrical bis(indolyl)alkanes
(PERGAMON-ELSEVIER SCIENCE LTD, 2006-02-01)Silicotungstic acid, H4SiW12O40, an important Keggin heteropoly acid, efficiently catalysed the reaction of indoles with aryl aldehydes in ethyl acetate solution at room temperature to furnish symmetrical bis(indolyl)alkanes ... -
Application of sulfamic acid as an eco-friendly catalyst in an expedient synthesis of benzimidazoles
(PERGAMON-ELSEVIER SCIENCE LTD, 2006-05-01)Sulfamic acid, an eco-friendly and zwitterionic solid, proved to be a very efficient catalyst for the reaction of ortho-phenylenediamine with aryl aldehydes in ethanol at room temperature to furnish both 1-arylmethyl-2-aryl- ... -
Mild deprotection of tert-butyl carbamates of NH-heteroarenes under basic conditions
(TAYLOR & FRANCIS INC, 2006)Aqueous methanolic potassium carbonate under reflux has been demonstrated to be a highly effective deprotective agent for the tert -butyl carbamates of indoles, indazoles, carbazole, thiazoloindole, and pyrrole. The method ... -
Phosphoric acid-on-silica gel: A green catalyst for the synthesis of symmetrical bis(indolyl)alkanes
(PERGAMON-ELSEVIER SCIENCE LTD, 2006-08-01)Orthophosphoric acid, adsorbed on TLC-grade silica gel, has been demonstrated to be an efficient green catalyst for an expeditious and solvent-free one-step synthesis of symmetrical bis(indolyl)alkanes from the reaction ... -
An expeditious approach to Knoevenagel condensation of Meldrum's acid on neutral alumina using microwave irradiation
(BENTHAM SCIENCE PUBL LTD, 2006-11-01)Application of microwave irradiation to Meldrum's acid and aryl aldehydes, both adsorbed on neutral alumina, furnished efficiently the corresponding Knoevenagel condensation products remarkably fast. -
Magnetic field effect on photoinduced electron transfer between dibenzo[a,c]phenazine and different amines in acetonitrile - water mixture
(AMER CHEMICAL SOC,, 2007-02-08)Unlike the simple phenazine (PZ) molecule, one of its derivatives, dibenzo[a,c]phenazine (DBPZ) forms a charge-transfer complex in the triplet state ((ECT)-E-3) with different amines, e.g., N,N-dimethylaniline (DMA), ... -
Reaction of diethyl mesoxalate with active methylene compounds: An interesting outcome
(SCIENTIFIC PUBL-INDIA, 2008-02-01)Diethyl mesoxalate reacts separately with each of Meldrum's acid, indan-1,3-dione and diethyl malonate - all active methylene compounds - on neutral alumina either at room temperature or under microwave irradiation to ... -
Tosic acid-on-silica gel: A cheap and eco-friendly catalyst for a convenient one-pot synthesis of substituted benzimidazoles
(SPRINGER WIEN, 2007-12-01)2-Substituted and 1,2-disubstited benzimidazoles were prepared efficiently from o-phenylenediamines and aryl aldehydes using p-toluenesulphonic acid (5∈mol%)-on-silica gel as a cheap and environmentally benign catalyst. -
One-pot formation of functionalised 2-piperidinones from arylidenecyanoacetates and methanolic ammonia via tandem reactions
(PERGAMON-ELSEVIER SCIENCE LTD, 2007-12-01)Aryl aldehydes react with ethyl cyanoacetate in methanolic ammonium acetate to expeditiously furnish, besides high yields of arylidenecyanoacetates, 4,6-diaryt-3,5-dicyano-5-ethoxycarbonyl-2-piperidinones in low yields. ... -
A Keggin heteropoly acid as an efficient catalyst for an expeditious, one-pot synthesis of 1-methyl-2-(hetero)arylbenzimidazoles
(PERGAMON-ELSEVIER SCIENCE LTD, 2007-07-23)The Keggin heteropoly acid, silicotungstic acid, H4SiW12O40, has been demonstrated to be highly efficient for an expeditious, one-pot synthesis of 1-methyl-2-(hetero)arylbenzimidazoles from N-methyl-1,2-phenylenediamine ... -
Expeditious reaction of ninhydrin with active methylene compounds on montmorillonite K10 clay
(SPRINGER WIEN, 2009-02)Ninhydrin reacted expeditiously with thirteen active methylene compounds on montmorillonite K10 clay at room temperature to furnish, in 5 min, a Knoevenagel condensate in one case, aldols in six cases, aldol-derived cyclic ... -
REACTION OF ISATINS WITH ACTIVE METHYLENE COMPOUNDS ON NEUTRAL ALUMINA: FORMATION OF KNOEVENAGEL CONDENSATES AND OTHER INTERESTING PRODUCTS
(PERGAMON-ELSEVIER SCIENCE, 2009-01-01)Isatin and its N-methyl and 5-nitro derivatives underwent smooth reaction with a variety of acyclic and cyclic active methylene compounds on neutral alumina at rt to efficiently furnish Knoevenagel condensates in the ... -
An expedient, regioselective synthesis of novel 2-alkylamino- and 2-alkylthiothiazolo[5,4-e]- and -[4,5-g]indazoles and their anticancer potential
(PERGAMON-ELSEVIER, 2008-07-07)Several novel 2-alkylamino- and 2-alkylthiothiazolo[5,4-e]- and -[4,5-g]indazoles and their 6-alkyl and 8-alkyl derivatives have been synthesised in high overall yields starting from 5-nitro and 6-nitro-indazoles in a ... -
A mild and expedient one-pot synthesis of substituted benzimidazoles in water using a phase-transfer catalyst
(SPRINGER, 2009-04)1-Alkyl/phenyl-2-arylbenzimidazoles have been synthesized in very good to excellent yields by a one-pot condensation of N-alkyl/phenyl-o-phenylenediamines with aryl aldehydes in water at room temperature using cetyl-pyridinium ... -
An expedient synthesis of novel 2-substituted thiazolo[4,5-f]isoquinolines/quinolines and benzo[1,2-d:4,3-d ']bisthiazoles and their potential as inhibitors of COX-1 and COX-2
(ARKAT USA, 2010-11-07)An efficient, general synthesis of 2-substituted thiazolo[4,5-f]isoquinolines, thiazolo[4,5-f]quinolines and benzo[1,2-d:4,3-d']bisthiazoles has been accomplished from 5-nitroisoquinoline/quinoline and 6-nitrobenzothiazole, ...
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