REACTIONS OF 1,2,5-THIADIAZOLE-3,4-DICARBONITRILE

The known compound 1,2,5-thiadiazole-3,4-dicarbonitrile, la preferenti ally forms mono addition compounds 3, but also bis-addition compounds 4 with oxygen, nitrogen and sulfur nucleophiles. One preparation of 1a produced s[4-cyano-1,2,5-thiadiazol-3-ylmethyl(imino)]amine 2 as a mi nor product. The structure of compound 2, the facile formation of tria zine 5 and the monocyclic structures of 3 and 4 indicate extensive ste reoelectronic interactions between vicinal substituents of 1.2,5-thiad iazole. A bicyclic diimino imide was not formed from la in sulfur- or methoxide-catalysed reactions with ammonia in methanol.