Synthesis of 2,3-dihydropyrido- and 2,3-dihydropyrimido-[1,4]diazepines from triaminopyridine and triaminopyrimidine

The reaction of 2,3,6-triaminopyridine 1 and 4,5,6-triaminopyrimidine 2 with one equivalent of the chal-cones 3, in acetic acid, leads to the formation of the 8-amino-2,3-dihydro-1H-pyrido2,3-b]1,4]diazepine and 6-amino-2,3-dihydro-1H-pyrimido4,5-b]1,4]diazepine derivatives 4 and 5 . The products were characterized by NMR techniques such as ¹³C, ¹H, and DEPT including selective ¹³C{¹H} decoupling experiments.