| Abstract: | Syntheses and reactions of 4-carboxy-2-pyrrolidone, 6,6-dimethyl-4-carboxy-2-piperidone, and 5,5-dimethyl-4-carboxy-2-pyrrolidone are described. Whereas 4-carboxy-2-pyrrolidone polymerizes upon heating to form a polyimide, the two lactams containing geminal dimethyl groups undergo isomerization. The 6,6-dimethyl-4-carboxy-2-piperidone isomerizes to 5,5-dimethyl-3-carboxymethyl-2-pyrrolidone, and 5,5-dimethyl-4-carboxy-2-pyrrolidone affords isopropylidene succinimide. Possible mechanisms for these reactions are discussed. |
