The present paper deals with the synthesis of novel dihydropyranone and dihydropyrano [2,3-d][1,3]dioxinedione derivatives via one-pot three-component reaction between Meldrum's acid, arylaldehydes, and various 1,3-dicarbonyls in the presence of KOH as a base in H2O:EtOH under thermal and ultrasound irradiation. It was observed that ultrasound-assisted method gave 80-94% yields in 30-45 min as against 120-280 min required to get 60-82% yields by thermal method.

Arylidene Meldrum's acid is employed as a source of the aryl group and oxidant for the synthesis of 2-aryl-1 H–benzimidazoles by a condensation reaction with 1,2-phenylenediamine in refluxing ethanol with good to high yields. Arylidene Meldrum's acids were also used as a source of the aryl group and oxidant for the synthesis of 2-aryl-1 H-perimidines by a condensation reaction with 1,8-diaminonaphthalene in refluxing ethanol with high yields.

An efficient and simple method for the synthesis of 1-aryl-1,2-dihydro-benzo[f]chromen-3-ones via a one-pot three-component reaction of β-naphthol, arylaldehydes and Meldrum's acid with Et3N as a base in CH3CN under reflux is reported. All the products were obtained in good to excellent yields and their structures were established from their spectroscopic data.

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