Acetic Anhydride → alpha-Methylene-4-methoxybenzenepropanoic acid

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Reaction Steps

4-Methoxybenzylmalonic acid, (20.2 g., 0.09 mol) was suspended in N,N,N1,N1 -tetramethylmethanediamine (45 ml). Acetic anhydride (45 ml) was added dropwise, keeping the temperature below 45° C. by cooling in an ice-bath as necessary. The resulting clear solution was stirred for 11/2 hour at ambient temperature and then was poured into ice and water. The white solid product was collected, combined with comparable product from a second 0.083 mol run, and dried at 0.1 mm at room temperature to give 22.4 g. (68%) of product, m.p. 88°-91° C. A sample recrystallized from ether-petroleum ether melted at 90°-93° C.

Provenance & Evidence