(S)-2-amino-3-[4-(1,3,6-trimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yl)phenyl]propionic acid methyl ester hydrochloride 、
1-(2-methoxyethyl)cyclopentane carboxylic acid 在
O-(1H-benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate 、
N,N-二异丙基乙胺 作用下,
以
N,N-二甲基甲酰胺 为溶剂,
以72%的产率得到N-[[1-(2-methoxyethyl)cyclopentyl]carbonyl]-4-(1,3,6-trimethyl-2,4-dioxo-5-pyrimidinyl)-L-phenylalanine methyl ester