An Efficient and Novel Protocol for the Synthesis of Pyrazolo[5,1-a]isoindole Derivatives

Abstract

Fused pyrazole systems are biologically important molecules. An efficient two-step protocol has been developed to make new molecules of this family via the reaction between dimethyl acetylenedicarboxylate, triphenylphosphine and N-aminophthalimide in the presence of benzoic acid or N-aminophthalimide derivatives. This reaction occurred easily in an ambient temperature to give stable phosphorus ylides, which, upon heating, underwent an intramolecular Wittig reaction to afford the pyrazolo[5,1-a]isoindole derivatives.