Pyridine → Methyl N-(oxomethylidene)phenylalaninate

Participants

Reaction Conditions

Reaction Steps

A well-stirred cold mixture (0° C.) of phenylalanine methyl ester hydrochloride (200 mg), anhydrous dichloromethane (3 ml), and anhydrous pyridine (295 μl, 4 eq.) was stirred for 15 min. A 2M phosgene solution in toluene (455 μl, 0.98 eq.) was added over 30 sec. followed by stirring for 2 h at 0° C. The reaction mixture was poured into dichloromethane washed with cold IN hydrochloric acid then ice water. Each aqueous layer was back extracted once with dichloromethane. The combined organic layer was washed once with brine, dried over anhydrous magnesium sulfate and concentrated. Distillation under vacuum afforded methyl (S)-2-isocyanato-3-phenylpropanoate (125 mg).

Provenance & Evidence