Synthesis of N‐Sulfonyl Pyrazoles Through Cyclization Reactions of Sulfonyl Hydrazines with Enaminones Promoted by p‐TSA

A strategy for the rapid synthesis of 3‐substituted N‐sulfonyl pyrazoles via p‐TSA‐promoted cyclization reactions of sulfonyl hydrazines with N,N‐dimethyl enaminones has been developed. This method achieves both the formation of pyrazole ring and the continued retention of sulfonyl group, providing a series of 3‐substituted N‐sulfonyl pyrazoles in moderate to good yields with good functional group tolerance, easily available starting materials, and can be scaled‐up.