Catalyst-free one-pot synthesis of 1,4,5-trisubstituted pyrazoles in 2,2,2-trifluoroethanol

A simple, efficient and three component one-pot synthesis of 1,4,5-trisubstituted pyrazoles by condensation of β-dicarbonyls, N,N-dimethylformamide dimethyl acetal (DMFDMA) and hydrazine derivatives in 2,2,2-trifluoroethanol without using any catalyst and activation, is described.

Graphical abstractA simple and efficient method for the preparation of 1,4,5-trisubstituted pyrazoles by the reaction of β-dicarbonyls, N,N-dimethylformamide dimethyl acetal (DMFDMA) and hydrazine derivatives is described in 2,2,2-trifluoroethanol without use of a catalyst or any other additive.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A catalyst free method for the synthesis of trisubstituted pyrazoles is introduced. ► This method shows a generality for various dicarbonyls. ► Regioselective synthesis of 1,3,4-trisubsituted pyrazoles is achieved in TFE. ► A simple high yield and mild one pot transformation.