Strategy To Prepare 3-Bromo- and 3-Chloropyrazoles

J Org Chem. 2018 Mar 2;83(5):2830-2839. doi: 10.1021/acs.joc.7b03282. Epub 2018 Feb 19.

Abstract

A general strategy to prepare substituted 3-bromo- and 3-chloropyrazoles is described. The three-step method involves condensation of crotonates or β-chloro carboxylic acids with hydrazines, followed by halogenation and oxidation. Several condensation and oxidation protocols were developed to enable preparation of a wide variety of 3-halopyrazoles with good to excellent yields and regiocontrol.

Publication types

  • Research Support, Non-U.S. Gov't