Microwave-assisted efficient synthesis of spiro-fused heterocycles under solvent-free conditions

Spiro-fused heterocycles were synthesized in good to high yields by a pseudo four-component reaction of an aldehyde, urea and a cyclic beta-diester or a beta-diamide such as Meldrum's acid or barbituric acid derivatives using microwave irradiation under solvent-free conditions. (C) 2004 Elsevier Ltd. All rights reserved.