Abstract The hydrolysis at pH 7.5 in the presence of immobilized benzylpenicillin acylase of the N-phenacetyl derivatives of the primary amines (3)-(5) affords the hydroxy amines (6)- (8), key intermediates in the synthesis of optically active forms of carnitin and propranalol, of ca. 0.4, 0.3 and 0.8 ee, respectively.