Regioselective Synthesis of 3,5-Disubstituted Pyrazoles

Highly Regioselective Synthesis of 3,5-Substituted Pyrazoles from Bromovinyl Acetals and N-Tosylhydrazones: A. Westermeyer, Q. Llopis, G. Guillamot, P. Phansavath, V. Ratovelomanana-Vidal
Synlett 2020, 31, DOI: 10.1055/s-0039-1690885


The pyrazole ring is frequently encountered in pharmaceuticals and bioactive compounds, therefore representing an important synthetic target for organic and medicinal chemists. Although a number of methods are available for assembling the pyrazole ring, there is still a need for efficient and selective methods for preparing selectively substituted pyrazoles. Recently, the group of Dr. Phannarath Phansavath and Dr. Virginie Ratovelomanana-Vidal from Chimie ParisTech-CNRS (France) described a new approach to the 3,5-disubstituted pyrazole scaffold.

Dr. P. Phansavath and Dr. V. Ratovelomanana-Vidal said: “The regioselective 1,3-dipolar cycloaddition of diazo compounds, generated in situ from N-tosylhydrazones, with unactivated bromovinyl acetals provides an efficient and cost-effective access to 3,5-disubstituted pyrazoles, which are valuable heterocycles in the pharmaceutical industry and agribusiness.”

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