A FACILE, ONE-POT SYNTHESIS OF NOVEL 2,2'-BI(4,5-DIHYDRO-1,3,4-SELENADIAZOLE) DERIVATIVES VIA DIHYDRAZONOYL DIHALIDES

N,N'-Diaryloxalodihydrazonoyldichlorides 1 react with potassium seleno cyanate (or selenourea), in ethanol, leading to the formation of the h itherto unreported bi(4-aryl-4,5-dihydro-5-imino-1,3,4-selenadiazoles 3 in good yields. Compounds 3 undergo nitrosation, acetylation and ben zoylation to afford the N-nitroso, N-acetyl and N-benzoyl derivatives 6, 8 and 9, respectively. Thermolysis of 6 afforded the corresponding 2,2'-biselenadiazol-5-ones 7 in high yields. The latter products were also obtained directly from acid hydrolysis of 3. Compounds 8 and 9 we re alternatively prepared, in one step, from the reaction of 1 with N- acetyl-N'-phenylselenourea and benzoylselenourea, respectively.