Ethyl chloroformate (I 15 mL, 1.29 mol) was added dropwise over a period of 90 min to a stirred solution of phthalimide (149.9 g, 1.02 mol) and triethylamine (160 mL, 1.15 mol) in dimethylformamide (500 mL) at 0-5" C under argon. The reaction mixture was allowed to warm to room temperature and stand for 4 h. It then was slowly added to an agitated mixture of ice and water (3 L). The solid product was collected and extracted with two portions of ...
