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