(2S,4R)-4-(4-chlorophenylthio)-N-(1-cyanocyclopropyl)pyrrolidine-2-carboxamide 、
lithium 1-(1-(ethoxycarbonyl)piperidin-4-yl)azetidine-2-carboxylate 以yielded ethyl 4-(2-((2S,4R)-4-(4-chlorophenylthio)-2-(1-cyanocyclopropylcarbamoyl)pyrrolidine-1-carbonyl)azetidin-1-yl)piperidine-1-carboxylate 1:1 epimers as a white solid (70%)的产率得到ethyl 4-(2-((2S,4R)-4-(4-chlorophenylthio)-2-(1-cyanocyclopropylcarbamoyl)pyrrolidine-1-carbonyl)azetidin-1-yl)piperidine-1-carboxylate