Knorr Pyrazole Synthesis

The preparation of pyrazole derivatives from 1,3‐dicarbonyl compounds and hydrazines is known as the Knorr pyrazole synthesis. The study finds that similarly pyrazole derivatives can also be prepared from hydrazines and equivalent molecules of 1,3‐dicarbonyl compounds. The study represents other reactions, such as β‐carbonyl aldehyde with hydrazine and β‐carbonyl ester with hydrazine to understand the mechanism of the reaction. This reaction has general application in the preparation of pyrazole derivatives.