P. Kover et al., An unexpected valence bond isomerization to the heteroaromatic ring system: [1,2,3]triazolo[4,5-d]pyridazine, CHEM COMMUN, (18), 2000, pp. 1785-1786
The arylazo substituted salt 2 when treated with a base underwent a valence
bond isomerization to yield a derivative of the heteroaromatic ring system
, [1,2,3]triazolo[4,5-d]pyridazine (4).