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

<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

Pure Water-Induced Dehalogenation of 2,4-Di-<i>tert</i>-amino-6-substituted-5-halogenopyrimidines

Dehalogenation of 5-halogenopyrimidine derivatives in boiling pure water was accomplished in high yields. The substrate and pure water are the only two reaction components in this process. Dehalogenation takes place in the absence of any catalysts, additives, basic, or acidic conditions, introducing water as a potential dehalogenation reagent

Synthesis of 2-substituted-4-methyl-5,13-dihydropyrimido[4′,5′:5,6][1,4]thiazepino[2,3-<i>b</i>]quinoxaline as a new heterocyclic system

<p></p> <p>2-Substituted-4-methyl-5,13-dihydropyrimido[4′,5′:5,6][1,4]thiazepino[2,3-<i>b</i>]quinoxalines (<b>7a-g</b>), derivatives of a new heterocyclic system were synthesized through cyclocondensation of 2,4-dichloro-5-(chloromethyl)-6-methylpyrimidine (<b>3</b>) with 3-aminoquinoxaline-2-thiol (<b>4</b>) and subsequent substitution by various secondary amines. Regioselective heterocyclization was confirmed by X-ray crystallographic analysis for 4-methyl-2-(pyrrolidin-1-yl)-5,13-dihydropyrimido[4′,5′:5,6] [1,4]thiazepino[2,3-<i>b</i>]quinoxaline <b>(7a).</b></p