CAL-B-catalyzed resolution of some pharmacologically interesting β-substituted isopropylamines

Some pharmacologically active amines such as amphetamine, the isomeric o-, m- and p-methoxyamphetamines, 4-phenylbutan-2-amine and mexiletine, as well as their corresponding acetamides, have been prepared in high yields and with very high enantiomeric excesses. The method consists of the Candida antarctica lipase B (CAL-B)-mediated enantioselective acetylation of racemic amines using ethyl acetate as solvent and acyl donor. The enzyme follows KazlaUskas' rule with all amines, (R)-amides being obtained as the major enantiomer in all cases. From the conversion values measured for both enantiomers, it can be deduced that the size of the substituents attached to the stereocenter is responsible for the enantioselectivity and rate of some of these reactions. (C) 2002 Elsevier Science Ltd. All rights reserved.