Microwave-assisted Synthesis of New Regioisomeric 6,7-Dihydroindeno[1,2-e]pyrimido[4,5-b][1,4]diazepin-5(5aH)-ones

Novel 11-amino-6-aryl-6,7-dihydroindeno[1,2-e]pyrimido[4,5-b][1,4]diazepin-5(5aH)-ones 4a-f were prepared regioselectively by the tricomponent reaction of 4,5,6-triaminopyrimidine 1, 1,3-indandione 2 and aromatic aldehydes 3a-f. The bicomponent approach, using 2,4,5,6-tetraaminopyrimidine 5 and 2-arylideneindandiones 6a-f as reagents, afforded 9,11-diamino-6-aryl-6,7-dihydroindeno[1,2-e]pyrimido[4,5-b][1,4]diazepin-5(5aH)-ones 7a-f in good yields and the regioisomeric 8,10-diamino derivatives 8a-c in lower yields. Both, bi- and tricomponent approaches were performed by microwave irradiation and all products were fully characterized by detailed NMR measurements.