Dicyclohexylcarbodiimide → tertiary butyloxycarbonylglycyl-epsilon-benzyloxycarbonyl-L-lysyl-sarcosyl-L-proline methyl ester

Participants

Reaction Steps

To 50 ml of a solution of 2.79 g (0.0078 mol) of tertiary butyloxycarbonylglycine dicyclohexylamine salt and 3.96 g (0.0078 mol) of ε-benzyloxycarbonyl-L-lysyl-sarcosyl-L-proline methyl ester hydrochloride in chloroform, 5 ml of a solution of 1.61 g (0.0078 mol) of dicyclohexylcarbodiimide in chloroform was added at -10° C. Thereafter, the resultant mixture was treated by the procedure followed in the preparation of α-tertiary butyloxycarbonyl-ε-benzyloxycarbonyl-L-lysylsarcosyl-L-proline methyl ester in (A) above including such step as stirring at -10° C. for five hours and at room temperature overnight, for example. Consequently, there was obtained 3.55 g (yield 73%) of tertiary butyloxycarbonylglycyl-ε-benzyloxycarbonyl-L-lysyl-sarcosyl-L-proline methyl ester in white solid form having a melting point of 52° to 54° C.

Provenance & Evidence