Catalyst-free reactions under solvent-free conditions: microwave-assisted synthesis of heterocyclic hydrazones below the melting points of neat reactantsDedicated with deep respect to Professor Miha Tišler, University of Ljubljana, Slovenia on the occasion of his 75th birthday.

Abstract

The reaction of neat 5- or 8-oxobenzopyran-2(1H)-ones, 1–3, with a variety of aromatic and heteroaromatic hydrazines, 4, is remarkably accelerated upon irradiation in a household microwave oven in the absence of any catalyst, solid support or solvent thus providing an environmentally friendly route to several heterocyclic hydrazones.