An efficient three-component protocol for the synthesis of novel spiro-oxazinobarbiturates

Some novel spiro-oxazinobarbiturate derivatives have been successfully synthesized in a one-pot, three-component cascade reaction from various azines (pyridine, isoquinoline, quinoline and phenanthridine), 1,3-dimethylalloxan, and several activated acetylenes (alkyl propiolates, dialkyl acetylenedicarboxylates, and butyne-2-one). The high bond forming efficiency (formation of new C–N, C–C, and C–O bonds) of this reaction makes it attractive for the synthesis of spiro-oxazinobarbiturates in a single operation.