PROCESS FOR PREPARING GALANTHAMINE DERIVATIVES BY ASYMMETRIC REDUCTION

摘要

A process for preparinga compound of formula (3)in enantio-enriched form,comprises reducing a compoundof formula (4) using anasymmetric enantiospecificreductant, wherein A1 = A2 =H or A1, A2 = O; B1 = B2 =H or B1, B2 = O; Z = H, C1-20alkyl or a precursor thereof,or a removable protectinggroup for nitrogen, e.g. acylor alkyloxycarbonyl; Y = H ora substituent; R1 = C1-20 alkyl;and R is an optional, additionalsubstituent.