Studies in the chemistry of polyhalogenobenzene compounds. The synthesis and reactivity of 2,3,5,6- and 2,3,4,5-tetrachlorobenzenesulphonyl chlorides and related compounds

Abstract

2,3,5,6-Tetrachlorobenzenesulphonyl chloride (2) and pentachlorobenzenesulphonyl chloride (4) have been obtained from the corresponding sulphonic acids (3) and (5) by treatment with phosphorus pentachloride. The sulphonyl chlorides have been characterized as a series of polychlorobenzene- sulphonamides, some of which have been converted into N-trichloromethylsulphenyl derivatives. The reaction of 1,2,4,5-tetrachlorobenzene with chlorosulphonic acid has been reinvestigated; comparatively short reaction periods gave mainly bis(pentachloropheny1) sulphide, and prolonged heating afforded hexachlorobenzene. Possible routes to these products are briefly discussed. Attempts to obtain 2,3,5,6-tetrachlorobenzenesulphonohydrazide (10) were unsuccessful; but the corresponding sulphonyl azide (11) has been prepared and its reactions with triphenylphosphine, norbornene and cyclohexene investigated.