Solid‐Phase Synthesis of Substituted Pyrazolones from Polymer‐Bound β‐Keto Esters

Abstract

Polymer-bound acetoacetate 3 was γ-mono- and γ-dialkylated, as well as α-monoalkylated, to give 6, 9, and 13, respectively. Treatment with hydrazine or substituted hydrazines followed by thermal or acidic cyclizing cleavage yielded the pyrazolones 17a−dd in a purity of >90%.