Uttam R. Kalkote

An Efficient Oxidation of 1,4-Dihydropyridines Using Aqueous tert.-Butylhydroperoxide

Abstract Aromatization of 4-substituted 1,4-dihydro-2,6-dimethyl-3,5-pyridine dicarboxylate using aqueous tert.-butylhydroperoxide in 74–87% yield has been achieved.

An Efficient Co(II) Catalyzed Auto Oxidation of 1,4-Dihydropyridines

Abstract An efficient Co(II) catalyzed auto oxidation of 1,4-dihydropyridines to pyridines in good to excellent yield is described.

Sn-β molecular sieve catalysed Baeyer-Villiger oxidation in ionic liquid at room temperature

Efficient oxidation of aryl ketones to esters at room temperature with 30% aqueous H2O2 and catalytic Sn-β-molecular sieve in ionic liquid was established.

Enzymatic kinetic resolution studies of racemic 4-hydroxycyclopent-2-en-1-one using Lipozyme IM®

Abstract Enzymatic kinetic resolution studies of (±)-4-hydroxycyclopent-2-en-1-one 2 were taken up in organic solvents by transesterification with vinyl acetate and alcoholysis of its acetate 3 as an alternative to the desymmetrization of meso-cyclopentenediol to provide faster and economic access to enantiomerically pure 4-(R)-tert-butyldimethylsilyloxycyclopent-2-en-1-one 1. Parameters were screened using Lipozyme IM® as catalyst. Although enantioselectivity observed was moderate (E=24, by alcoholysis of 3 with 2-butanol), trends in the effect of solvent, water content and alcohol structure showed useful directions for screening of other enzymes for optimization of the method to useful levels of efficiency.

A Simple and Economical Method for the Alkylation of Benzanilides1

Abstract A convenient and economically feasible method for the alkylation of benzanilides using tetra-n-butyl hydrogen sulphate phase transfer catalyst, powdered NaOH and anhydrous K2 CO 3 is described.

Short and Efficient Synthesis of Rubrolide E

Abstract Short and efficient synthesis of rubrolide E from commercially available 4‐methoxyacetophenone, employing ring‐closing metathesis, Knoevenagel condensation, and Reformatsky reactions, are the key steps are described.

The oxidation of 4-alkyl and 4-aryl-1,4-dihydropyridines to pyridines with hydrogen peroxide in an ionic liquid

An efficient oxidation of 4-alkyl and 4-aryl-1,4-dihydropyridines to the corresponding pyridines with hydrogen peroxide in ionic liquids at room temperature in excellent yields is described.

Desymmetrization of meso-cyclopenten-cis-1,4-diol to 4-(R)-hydroxycyclopent-2-en-1-(S)-acetate by irreversible transesterification using Chirazyme®

Abstract The parameter optimization study for the desymmetrization of meso-cyclopenten-1,4-diol 1 through irreversible transesterification using an immobilized lipase from Mucor meihei, i.e., Lipozyme®/Chirazyme® is presented. The enzyme was studied for the transesterification of 1 in various organic solvents by varying reaction parameters such as the nature of acyl donor, temperature, enzyme quantity etc., to afford optically active 4-(R)-hydroxycyclopent-2-en-1-(S)-acetate 2 of >98% enantiomeric excess in >60% yield.

Quinolone antibiotics: Study of reactivity and impurity profile of piperazine with chloro-fluoro-quinolone carboxylic acid in aqueous medium

Abstract The reaction of 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,2-dihydroquinoline-3-carboxylic acid with piperazine in water was studied. The product ciprofloxacin was isolated and the impurity formed in the reaction was isolated and characterized as 1-cyclopropyl-7-chloro-6-piperazinyl-4-oxo-1,2-dihydroquinoline-3-carboxylic acid. Similarly norfloxacin was also synthesised.

Novel orthohalogenation reaction. Synthesis of orthochloroarylamines from nitroarenes.

Abstract Thionyl chloride reacts with N-phenylbenzo and N-phenylacetohydroxamic acids at low temperatures to give ortho-chloroanilide derivatives in good yield.