Wawzonek rearrangement

For all of the complexes 1, except la, the only detectable product of the reaction with 8 was the six-membered chelate 11. However, heating of compounds 11 up to their melting points (mp), or for prolonged periods of time in solution, led to conversion to 10 (Eq. 8).33,34 This reaction is analogous to the Wawzonek rearrangement of hydrazide-ylides (Eq. 9).39... 

Aran has studied the reactivity of 1,1-disubstituted indazol-3-ylio oxides <93JCS(Pl)ill9>, for instance, treatment of these compounds with hydrochloric acid affords the corresponding 3-hyd-roxyindazoles the Wawzonek rearrangement (formation of 1,2-disubstituted indazolinones) was also observed. 

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