EFFECTIVE PREPARATION OF OPTICALLY-ACTIVE 4,4,4-TRIFLUORO-3-(INDOLE-3-) BUTYRIC-ACID, A NOVEL PLANT-GROWTH REGULATOR, USING LIPASE FROM PSEUDOMONAS-FLUORESCENS

Optical resolution of 4,4,4-trifluoro-3-(indole-3-)butyric acid (TFIBA ), a novel plant growth regulator, was achieved by Pseudomonas fluores cens lipase (lipase AK)-catalyzed enantioselective hydrolysis of its t rifluoroethyl ester. Compared with the reactivity of lipase AK for TFI BA ethyl ester, that for TFIBA trifluoroethyl ester was markedly incre ased, and the reaction was complete within Ih at 40 degrees C in phosp hate buffer containing 10% tert-amyl alcohol. The reactivity of lipase AK for TFIBA trifluoroethyl ester was similar to that for two other T FIBA esters (fluoroethyl and difluoroethyl), and higher than that for other esters (chloroethyl, trichloroethyl, and tribromoethyl). These r esults suggest that the introduction of fluorine atom(s) into an alcoh olic group is an effective way to increase the rate of hydrolysis by l ipase AK.