Showing papers by "Anju Chadha published in 2002"

Biocatalytic deracemisation of α-hydroxy esters: high yield preparation of (S)-ethyl 2-hydroxy-4-phenylbutanoate from the racemate

Abstract: Biocatalytic deracemisaton of the racemic ethyl ester of 2-hydroxy-4-phenylbutanoic acid gives the ( S )-enantiomer exclusively in >99% e.e. and 85–90% yield. Ethyl and methyl esters of mandelic acid and the methyl ester of 2-hydroxy-4-phenylbutanoic acid also gave the ( S )-enantiomer exclusively. Whole cells of Candida parapsilosis (ATCC 7330) were used to effect this biotansformation.

Pseudomonas cepacia lipase--mediated transesterification reactions of hydrocinnamates.

Abstract: Use of lipase from Pseudomonas cepacia in transesterifcation reactions of ethyl hydrocinnamate with different alcohols has been examined. Among the alcohols tested, viz., n-butanol, iso-amyl alcohol, benzyl alcohol, n-octanol and 1-phenylethanol, only n-butanol yielded the transesterified product. Among the solvents tested, viz., n-heptane, n-hexane, cyclohexane, toluene, diisopropylether and n-butanol, the initial rate of transesterification proceeded in the order cyclohexane > n-heptane > n-hexane > diisopropylether > n-butanol > toluene. Using hexane as the solvent and a substrate to enzyme ratio of 1:5, the substrate to alcohol ratio was varied to maximize the yield. n-Butyl hydrocinnamate was obtained in 92% yield in 48 hr by employing a 1:1 (wt/wt) ratio of ethyl hydrocinnamate to lipase and a 1:5 (vol/vol) ratio of ethyl hydrocinnamate to n-butanol in hexane.