21737-17-7Relevant academic research and scientific papers
SYNTHESIS OF AZOXYBENZENE-SbCl5 COMPLEXES AND THEIR SELECTIVE ORTHO-WALLACH REARRANGEMENT
Yamamoto, Jiro,Nishigaki, Yukihiro,Umezu, Masahiro,Matsuura, Teruo
, p. 3177 - 3180 (1980)
When an equimolar solution of various azoxybenzenes and SbCl5 in carbon tetrachloride were mixed, a 1:1 complex immediately deposited as orange crystals in high yield.The thermal reaction of these complexes in inert solvents gives o-hydroxy-azobenzene selectively.On the contrary, other Lewis acids, such as TiCl4, AlCl3, FeCl3 and ZnBr2 failed to give an isolatable complex with azoxybenzene, and their direct thermal reaction with azoxybenzene resulted in deoxygenation to yield azobenzene as a main product.
Reaction of Haloazoxybenzenes with Sulfuric Acid
Shimao, Ichiro,Fujimori, Ken,Oae, Shigeru
, p. 546 - 550 (2007/10/02)
Treatment of 4,4'-dihaloazoxybenzenes with sulfuric acid afforded 4,4'-dihaloazobenzenes (6) as the major product and 5-halo-2-(p-halophenylazo)phenols, the Wallach rearrangement products as minor products, besides 2-halo-5-(halophenylazo)phenols, 2-halo-4-(p-halophenylazo)phenols, and 4-(p-halophenylazo)phenols as abnormal rearrangement products.The reaction of fluoro compounds gave the azophenols (3a or 5a) in the best yields.However, the ratio of 3a to 5a was found to vary with the concentration of sulfuric acid.Treatment of 4-haloazoxybenzenes with sulfuric acid gave 4-(p-halophenylazo)phenols and 4-haloazobenzenes (13) as major products together with 2-(p-halophenylazo)phenols and 5-halo-2-(phenylazo)phenols as minor products.Yields of reduction products 6 and 13 increased as the halosubstituent became heavier in the following sequence: F -> Cl -> Br -> I.
