4-Methylmorpholine → HCID 10403069, compound

Participants

Reaction Conditions

Reaction Steps

29.23 g of N-[(phenylmethoxy)carbonyl]-D-aspartic acid, 1,1-dimethylethyl ester, prepared as in Example C, in 120 mL dry tetrahydrofuran at -10° C. was treated with 10 mL N-methylmorpholine. The mixture was stirred for 3 min and 8.7 mL ethylchloroformate was added dropwise. The mixture was warmed to 23° C. over 15 min and filtered. The filtrate was added dropwise over 30 min to a vigorously stirred mixture of 7.7 g sodium borohydride in 60 mL water at 3° C. The cooling bath was removed, the mixture stirred at 21° C. for 3 h, then cooled to 0° C. and acidified to pH2 with concentrated HCl. The mixture was extracted with 3×200 mL ethyl acetate and the combined organic extracts were washed with brine, dried (Na2SO4) and evaporated to furnish a clear oil. Purification by silica chromatography using methylene chloride-acetone (9:1) as eluent gave the title compound as a clear oil; 21.6 g.

Provenance & Evidence