Microwave assisted enzyme catalysis for synthesis of n-butyl dipheyl methyl mercapto acetate in non-aqueous media

Abstract

n-Butyl dipheyl methyl mercapto acetate is an important pharmaceutical intermediate, having applications in the synthesis of Modafinil, a CNS stimulant drug. The current process is highly polluting and requires alternate green processes. Synthesis of it was carried out via lipase in the presence of microwave irradiation. Optimization of reaction conditions, such as catalyst loading, mole ratio of reactants, reaction temperature, water concentration and reusability of catalysts under the microwave irradiation was done. Among all, the commercially available lipases Novozym 435 was found best and gives the conversion 34% in 24 h at 60°C. A ping–pong bi–bi model with substrate n-butanol inhibition at higher concentration was found to be suitable for kinetics of the reaction.