Reaction of 2‐dimethylaminomethylene‐1,3‐diones with dinucleophiles. I. Synthesis of 1,5‐disubstituted 4‐acylpyrazoles

Abstract

Abstract Reaction of open‐chain and cyclic sym ‐1,3‐diones with N,N ‐dimethylformamide dimethyl acetal gave, generally in high yield, a series of sym ‐2‐dimethylaminomethylene‐1,3‐diones which reacted with phenylhydrazine and methylhydrazine to afford, generally in satisfactory yield, a number of 1,5‐disubstituted 4‐acylpyrazoles. The applications and limits of this new pyrazole synthesis are presented and discussed.