A new synthesis of triazolo[4,5-g]quinolines and unexpected ring reduced products by treatment with hydrazine hydrate

A new synthesis of the linear heterocycle 4-chloro-1H-triazolo[4,5-g]quinoline by reduction of the novel compound 4-chloro-1H-triazolo[4,5-g]quinoline-1-oxide is reported. Treatment of the latter with hydrazine hydrate in ethanol in a sealed steel vessel in the presence or not of palladised charcoal, under various conditions of both time and temperature, afforded some derivatives of both ring reduction and ring construction.