4-Methylmorpholine → N-[(1,1-Dimethylethoxy)carbonyl]-D-alanine 2,5-dioxo-1-pyrrolidinyl ester

Participants

Reaction Conditions

Reaction Steps

To a mixture of Compound (1) (560 mg.) and N-methylmorpholine (202 mg.) in dichloromethane (30 ml.), there was added isobutyl chloroformate (273 mg.) at -15°--20° C. and the mixture was stirred for 30 minutes at the same temperature. The mixture was cooled to -40° C. and, to this, there was added trimethylsilyl ester of Compound (2), which was prepared from Compound (2) (910 mg.) and bis(trimethylsilyl)acetamide (3 ml.) by stirring in a mixture of dichloromethane (20 ml.) and N,N-dimethylformamide (2 ml.). The mixture was stirred for 1 hour at -15°--20° C., and then treated in the same manner as the Step 1 of Example 57 to give Compound 3 (1.8 g.).

Provenance & Evidence