Abstract Several 6-oxo caprolactam derivatives have been prepared by the ring-expansion of enaminopyrrolidones with dimethyl acetylenedicarboxylate. Other acetylenic systems did not react. The products exist in the enol form of the β-keto ester system are are very resistant towards hydrolysis. They react with hydrazine and phenylhydrazine to form pyrazolo [3, 4-c] azepinones in low yield. Many of the caprolactams and their pyrazolo-fused derivatives ...
