Diethyl acetonedicarboxylate → Ethyl 5-(t-butoxycarbonyl)-4-[2-(m-chlorophenyl)ethyl]-3-ethoxycarbonylpyrrole-2-acetate

Participants

Reaction Steps

Crude t-butyl 5-(m-chlorophenyl)-2-hydroximino-3-oxopentanoate (43 g., 0.15 mol) and diethyl acetonedicarboxylate (28 ml, 30.3 g, 0.15 mol) are placed in a 1 liter round bottom flask and 250 ml of glacial acetic acid added. With stirring, 25 g (0.30 mol) anhydrous sodium acetate is added followed by 26 g Zn dust (94% fine, 0.364 mol) in a portionwise manner so that the exotherm does not bring the reaction to reflux. When addition is complete, the reaction is heated on a steam bath for one hour. The hot solution is then decanted from the residual zinc into 3 liters of ice water, and the resulting mixture is stirred vigorously until the oil solidifies. The mixture is then allowed to stand for 1.5 hours, and the solid is filtered. The solid is washed with water, dried in vacuo and recrystallized to give 21.5 g (31%) of ethyl 5-(t-butoxycarbonyl)-4-[2-(m-chlorophenyl)ethyl]-3-ethoxycarbonylpyrrole-2-acetate, M.P. 131°- 132°.

Provenance & Evidence