An efficient regioselective sonochemical synthesis of novel 4-aryl-3-methyl-4,5-dihydro-1H-pyrazolo[3,4-b]pyridin-6(7H)-ones

An efficient ultrasound-assisted preparation of a series of novel 4-aryl-3-methyl-4,5-dihydro-1H-pyrazolo[3,4-b]pyridin-6(7H)-ones via the reaction of 5-amino-3-methyl-1H-pyrazole, Meldrum's acid and various arylaldehydes using one-pot three-component approach is described. This rapid method produced the products in short reaction times (3-4 min) and excellent yields (87-95%).