Synthesis of pyridazine derivatives XXII. s‐triazolo[4, 3‐b]pyridazine 5‐oxides

Abstract

The synthesis of s‐triazolo[4,3‐b] pyridazine 5‐oxides is reported. To our knowledge, they are the first example of N‐oxides of heteroaromatic azoloazines with a bridgehead nitrogen. They are easily rearranged, in particular when irradiated with ultraviolet light, into 6‐hydroxy‐s‐triazolo[4,3‐b]pyridazines.