Synthesis of dihydropyranones and dihydropyrano[2,3-d][1,3]dioxine-diones by cyclization reaction of Meldrum’s acid with arylaldehydes and 1,3-dicarbonyls under thermal and ultrasound irradiation
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’sacid, arylaldehydes, and various 1,3-dicarbonyls in the presence of KOH as a base in H2O:EtOH underthermal and ultrasoundirradiation. It was observed that ultrasound-assisted method gave 80-94% yields in 30-45 min as against