CHIRAL RESOLUTION OF METHYL 2-ARYLOXYPROPIONATES BY BIOCATALYTIC STEREOSPECIFIC HYDROLYSIS

The hydrolysis of 2-aryloxypropionyl methyl esters by alpha-chymotryps in, lipase P and carboxylesterase NP was carried out to perform chiral resolution of their racemates. The biocatalytic activity of carboxyle sterase NP was undoubtedly higher than that of the other enzymes: in f act the reaction rate was greater and the enantioselectivity values we re better even though less amount of enzyme was employed. This enzyme was thus the most suitable to catalyze the enantiospecific hydrolysis of the tested compounds in aqueous media. The reaction was also attemp ted in organic solvents. The evaluation of the produced acid and the u nreacted ester was accomplished by chiral HPLC on Chiralcel OD, OD-H a nd Chiralpak AD columns. In general the configuration of the preferent ially hydrolyzed enantiomer was S, but for all the Compounds having an alkyl substituent (methyl or ethyl) on the 2 position of the aromatic ring the enantioselectivity of the enzymatic conversion was reverse. When compared, there did not appear to be any particular relationship between conversion, enantioselectivity data and chemical features (siz e or position of the substituents on the aromatic ring).