Transformations of 1-azinyl-4-ethoxycarbonyl thiosemicarbazides. The synthesis of 3-ethoxycarbonylamino-s-triazolo4,3-xazines

摘要

1-Azinyl-4-ethoxycarbonyl thiosemicarbazides4,5, and12and 1-azinyl-4-ethoxycarbonylmethyl thiosemicarbazide17, prepared from the corresponding heterocyclic hydrazino compounds and ethoxycarbonyl isothiocyanate or ethoxycarbonylmethyl isothiocyanate, were converted by oxidation with bromine in acetic acid into derivatives of fused 3-ethoxycarbonylamino-s-triazolo4,3-apyridine6, -pyridazine7, and -pyrazine13,18and20. The thiosemicarbazide derivative8was transformed at 0 °C into bis-s-triazolo4,3-b:3′4′-fpyridazine derivative9, while at room temperature 6-bromo-s-triazolo4,3-bpyridazine (10) was obtained. Further transformations of 8-substituted 3-ethoxycarbonylamino-s-triazolo4,3-apyrazines13and14afforded derivatives of bis-s-triazolo4,3-a:3′,4′-cpyrazine15and s-triazolo4,3-atetrazolo1′,5′-