Synthesis 2004(1): 43-52  
DOI: 10.1055/s-2003-44376
PAPER
© Georg Thieme Verlag Stuttgart · New York

Regioselective Synthesis of 1,3,5-Substituted Pyrazoles from Acetylenic Ketones and Hydrazines

Brian C. Bishop*, Karel M. J. Brands, Andrew D. Gibb, Derek J. Kennedy
Department of Process Research, Merck Sharp & Dohme Research Laboratories, Hertford Road, Hoddesdon, Hertfordshire EN11 9BU, UK
Fax: +44(1992)470437; e-Mail: brian_bishop@merck.com;
Further Information

Publication History

Received 6 October 2003
Publication Date:
17 December 2003 (online)

Abstract

The synthesis of diversely substituted 1,3,5-substituted pyrazoles from the reaction of acetylenic ketones with substituted hydrazines is reported. The reactions were shown to be highly regio­selective regardless of the nature of the substituents in the substrates and afforded essentially single pyrazole isomers in excellent yields.