The conversion of isothiazoles into pyrazoles using hydrazine

HA Ioannidou, PA Koutentis

Index: Ioannidou, Heraklidia A.; Koutentis, Panayiotis A. Tetrahedron, 2009 , vol. 65, # 34 p. 7023 - 7037

Full Text: HTML

Citation Number: 19

Abstract

The conversion of isothiazoles into pyrazoles on treatment with hydrazine is investigated. The influence of various C-3, C-4 and C-5 isothiazole substituents and some limitations of this ring transformation are examined. When the isothiazole C-3 substituent is a good nucleofuge, 3-aminopyrazoles are obtained. However, when the 3-substituent is not a leaving group it is retained in the pyrazole product. Treatment of 4-bromo-3-chloro-5- ...