On triazoles XXX. Synthesis of [1,2,4]triazolo-[1,5-d][1,2,4,6]tetrazepine-5-thiones

Different 2-Q-6,7,8,9-(bi-, tri- or tetra)substituted1,2,4]triazolo1,5-d]1,2,4,6]tetrazepine-5-triione derivatives representing a novel ring system were synthesised. In the case of 8-aryl-substituted derivatives ring-chain tautomerism was observed in DMSO-d₆ or deuteriochloroform solutions. In some cases both ring and chain tautomers could be isolated in crystalline form. The structure of products obtained was proved by nmr using also model compounds prepared for this purpose.