rac-trans-cyclopentane-1,2-dicarboxylic acid monoethyl ester 在
(benzotriazo-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate 、
三乙胺 作用下,
以
N-甲基吡咯烷酮 为溶剂,
以93%的产率得到rac-2-(4-{4-[(2-phenyl-5-trifluoromethyl-oxazole-4-carbonyl)-amino]-phenyl}-piperazine-1-carbonyl)-cyclopentanecarboxylic acid ethyl ester