4-[5-((3R)-5-oxopyrrolidin-3-yl)-2-chlorophenyl]benzoic acid 、
盐酸 、 (3R)-4-amino-3-(3-bromo-4-chlorophenyl)butanoic acid hydrochloride 以to provide the title compound (24)的产率得到4-{5-[(1R)-2-amino-1-(carboxymethyl)ethyl]-2-chlorophenyl}benzoic acid hydrochloride