A facile and stereoselective azepine-ring formation at the periphery of pyridone and pyrido[1,2-a]pyrimidone systems via intramolecular imine and carbonyl ene reactions

Article abstract of DOI:10.1016/0040-4020(96)00771-5

Thermal reaction of the N-alkyl and N-aryl imines of 2-(alk-2-enylamino)-4-oxo-4H-pyrido[1,2-a]pyrimidine 3-carboxaldehyde (9) gave pyrido[1',2':1,2]pyrimido[4,5-b]azepines 11-14 in good to excellent yields. Similarly, the imines of 4-(alk-2-enylamino)-1,