Proximity effects in diaryl derivatives. Part IV. Base-catalysed reactions of 2,2′-di(hydroxyamino)diaryl sulphones and of 2-(hydroxyamino)aryl phenyl sulphones

Abstract

Reaction of 2,2′-di(hydroxyamino)diaryl sulphones with sodium hydroxide in aqueous dioxan at 20° yields dibenzo [b,f][1,4,5]thiadiazepine 5,11,11-trioxides (X), phenazine 5-oxides (XIV), and phenazine 5,10-dioxides (XV). The formation of the phenazine derivatives probably involves disproportionation of the aryl hydroxylamines, followed by Smiles rearrangement, and then loss of the sulphino-group. In the presence of zinc, the arylhydroxylamines are converted into phenazines (IV) and thiadiazepine 11,11-dioxides (VII). The mechanism of the alkaline reduction of 2,2′-dinitrodiaryl sulphones¹ is discussed in the light of these results. Some of this work has been reported.²

Treatment of 2-(hydroxyamino)aryl phenyl sulphones with sodium hydroxide at 20° results in loss of the phenylsulphonyl group. For example, 6-chloro-2-(hydroxyamino)diphenyl sulphone affords sodium benzenesulphinate and 3,3′-dichloroazoxybenzene. Cleavage of a C–S bond does not occur in 4-(hydroxyamino)diphenyl sulphone. Possible mechanisms for the reaction are discussed.