Synthesis of Pyrimido[4,5-e]tetrazolo[5,1-b][1,3,4]thiadiazepine as a Novel Fused Heterocyclic System

Several derivatives of the novel fused seven-membered heterocyclic system of pyrimido[4,5-e]tetrazolo[5,1-b][1,3,4]thiadiazepine (5a–f) have been synthesized through the heterocyclization reaction of 2,4-dichloro-5-(chloromethyl)-6-methylpyrimidine (1) with sodium 1-amino-1H-tetrazole-5-thiolate (2) under basic conditions. Various derivatives were obtained via treatment with secondary amines.