Biorreduções de cetonas pró-quirais e nitrocompostos com células íntegras de Vigna unguiculata L. e produção enzimática de ésteres de cloranfenicol

Abstract

This work is divided into two parts: the first related biotransformations of organic compounds with the species Vigna unguiculata, and the second on the enzymatic synthesis of esters of chloramphenicol. Reactions bioreduction of ketones and nitrocompounds with grains of Vigna unguiculata (feijão de corda). After performing a reduction of acetophenone with screnning varying the reaction conditions, we found those that led to better results for conversion and enantiomeric excess. These conditions were applied to 34 other susbtratos, including: aliphatic ketones and aromatic ring with different substituents such as nitro, methoxy, and alkyl halide in various positions, nitro, β-keto ester, a ketone α, β-unsaturated and benzonitrile. Overall, the results obtained with the biorreduções can be considered satisfactory, as well as the enantiomeric excess values. In the second part, we used the commercial lipases: CAL-B, PSL-C (I) and PSL-C Amano in acylation reactions of the drug chloramphenicol, an exhaustive study in search of optimum reaction conditions mainly exploring the activity regioselective these enzymes. Were obtained from eight derivatives of this drug, depending on the acylating agent used, seven of these, and a monoacilados, di-acylated. As acyl donor was used several vinyl esters, saturated or not and with various chain lengths. Reaction parameters such as: variations of the solvent, temperature, concentration of the acylating agent and medium were optimized to obtain these derivatives. Virtually all products were obtained in high percentages of conversion, except for those with unsaturation. It is also carried out in a bench scale procedure using the enzyme CAL-B, and significant results were obtained in all cases. At the end of the study we adopted a procedure for recycling of the same enzyme, which was proven its efficiency in reuse.