One-pot synthesis of novel 1H-pyrimido[4,5-c][1,2]diazepines and pyrazolo[3,4-d]pyrimidines

Novel 1H-pyrimido [4,5-c][1,2]diazepines 3 & 4 and pyrazolo [3,4-d]pyrimidines 6 were regioselectively synthesised by the reaction of 1,3-dimethyl-6-hydrazinouracils 1 with various α,β-unsaturated compounds 2 and α-ketoalkynes 8 in excellent yields.