In a manner analogous to that described in Example 92, from 0.133 g of N-(benzyloxycarbonyl)-L-asparagine, 0.068 g of hydroxybenzotriazole, 0.103 g of dicyclohexylcarbodiimide and 0.16 g of N2 -[3(S)-amino-2(R)-hydroxy-4-phenylbutyl]-N1 -tert.butyl-4(R)-hydroxy-L-prolinamide, but using dichloromethane in place of ethyl acetate as the partitioning solvent and 20% methanol in dichloromethane for the chromatography and carrying out the re-evaporation with diethyl ether, there was obtained 0.1 g of N2 -[3(S)-[N-(benzyloxycarbonyl)-L-asparaginylamino]-2(R)-hydroxy-4-phenylbutyl]-N1 -tert.butyl-4(R)-hydroxy-L-prolinamide of melting point 115° C.
