New Bis(chalcones) and Their Transformation into Bis(pyrazoline) and Bis(pyrazole) Derivatives

Abstract

AbstractThe reaction of bis(chalcones) 1a−d and bis(chalcone) tetrabromo derivatives 3a−d with hydrazine hydrate gave bis(pyrazolines) 4a−d and bis(pyrazoles) 5a−d, respectively. Bis(pyrazoles) 5e,f bearing hydroxyphenyl substituents have been prepared from the reaction of bis(chromones) 6c,d with hydrazine hydrate, because their synthesis from the corresponding benzyloxy‐substituted 5c,d gave very poor yields. The structures of all new compounds have been established by extensive NMR spectroscopic studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)