反应详情

tert-Butyl (2RS,5SR)-1-{2-[3-(3-benzylcarbonylphenyl)ureido]acetyl}-5-phenylprolinate may be prepared as described in Example 41 §A, but starting from 0.4 g of tert-butyl (2RS,5SR)-5-(3-methylphenyl)-prolinate, 0.5 g of 2-[3-(3-benzyloxycarbonylphenyl)-ureido]acetic acid and 0.31 g of N,N'-dicyclohexyl-carbodiimide in 20 cm3 of acetonitrile. After treatment, 0.8 g of tert-butyl (2RS,5RS)-1-{2-[3-(3-benzyloxycarbonylphenyl)ureido]-acetyl}-5-phenylprolinate is obtained in the form of a meringue-like product, used as it is in the subsequent syntheses.