Strategy To Prepare 3‑Bromo- and 3‑Chloropyrazoles

Strategy To Prepare 3‑Bromo- and 3‑Chloropyrazoles

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...

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Veröffentlicht in:Journal of organic chemistry 2018-03, Vol.83 (5), p.2830-2839
Hauptverfasser: Fox, Richard J, Schmidt, Michael A, Eastgate, Martin D
Format: Artikel
Sprache:eng
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Zusammenfassung: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.
ISSN:0022-3263
1520-6904
DOI:10.1021/acs.joc.7b03282