AbstractEsters 1 of 1‐acyl‐2‐pyrrolidone‐3‐carboxylic acids 2 were hydrolized to 2 with acetic acid/HCl at 60–70°C. Reaction of 1a with formic acid/HCl at 60–75°C led to (not isolated) 2a which began to decarboxylate to 3a during the conversion of 1a to 2a even at this low temp. Decarboxylation of 2c‐f was accomplished at 160°C without solvent. Decarboxylative nitrosation of 2c‐f yielded the oximes 4c‐f of 1‐acyl‐2,3‐dioxopyrrolidines. Treatment of 4f with magic methyl provided the enol ether 5f of the respective dioxopyrrolidine.