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

Participants

Reaction Steps

Compound (1) was dissolved in dichloromethane (20 ml.) and N-methyl-morpholine (308 mg.) was added. This solution was cooled in a dry ice-acetone bath (-17°~-19° C.) under stirring, and to the solution, isobutylchlorocarbonate (417 mg.) was added. The reaction mixture was allowed to react for 20 minutes at the same temperature. To the resulting reaction mixture was added to the solution of Compound (2) (1.41 g.) in a mixture of dichloromethane (40 ml.) and N,N-dimethylformamide (4 ml) containing bis (trimethylsilyl)acetamide (3 ml.). The reaction mixture was stirred for 2 hours at -18° C. -10° C. and concentrated under reduced pressure to give an oily residue, which was dissolved in ethylacetate (100 ml.) and washed with 0.5N-Hcl. The organic layer was washed with brine and dried over MgSO4. Evaporation of the solvent gave a white foam which was throughly washed with ether to afford Compound (3) (2.42 g.) as white powder, mp. 145°~149° C. (decomp.)

Provenance & Evidence