A simple one pot synthesis of condensed 1,2,4-triazines by using the tandem A(N)-S-N(ipso) and S-N(H)-S-N(ipso) reactions

A new synthetic approach to condensed 1,2,4-triazines based on using the ta ndem A(N)-S-N(ipso) and S-N(H)-S-N(ipso) reactions has been developed. 5-Me thoxy-3-penyl-1,2,4-triazine and its NI-methyl quaternary salt were found t o react with C,N-, C,O- and NAP-bifunctional nucleophiles (m-phenylenediami ne, resorcinol, semicarbazide and ureas) into triazacarbazoles, benzofuro[2 ,3-e][1,2,4]-triazines, and 6-azapurine derivatives. In all cases nucleophi les attack first the unsubstituted C-6 carbon of the triazine ring, while t he final stage is replacement of the methoxy group affording cyclization pr oducts.