4-Hydroxybenzenesulfonyl chloride

Phosphorus pentachloride cannot be used in place of SOClj this reagent, however, can be used for preparation of 3,5-disubstituted-4-hydroxybenzenesulfonyl chlorides. Acenophtlu I,2-c furazane (2). This fura/ane (2) can be obtained in 55 % yield by dehydration of acenaphthoquinone dioxime (I) with thionyl chloride in methylene chloride. 

IIydroxybenzenesulfcmyl chloride. Sodium 4-hydroxybenzenesulfonate (1) can be converted into 4-hydroxybenzenesulfonyl chloride (2) in 80-90 % yield by treatment with... 

Phosphorus pentachloride cannot be used in place of SOCI2 this reagent, however, can be used for preparation of 3,5-disubstituted-4-hydroxybenzenesulfonyl chlorides.3... 

Though benzenesulfonyl chloride itself cannot form a sulfene by elimination of HC1, various substituted arenesulfonyl chlorides have this potential. The very first discussion of sulfenes in the literature54 concerned the possibility of sulfene formation from a substituted 4-hydroxybenzenesulfonyl chloride (10) as in equation 10. Subsequent studies clarified the nature of the product (which was polymeric)55,56 and of the yellow color ascribed by the early workers to the sulfoquinone intermediate relatively recently a good kinetic case has been presented57 for the reaction of 10 (X = Me) according to equation 10. 

The orientation of chlorosulfonation of the 2,4- and 2,5-dichlorophenols was confirmed by NMR studies. However, in the case of 3,5-dichlorophenol 133, it was shown that the reaction gave not only the previously reported 2,6-dichloro-4-hydroxybenzenesulfonyl chloride 134, but also the 2,4-dichloro-6-hydroxy isomer 135 in which chlorosulfonation has occurred ortho to the hydroxyl group (Equation 43). 

Treatment of the o-hydroxybenzenesulfonyl chloride (146) with pyridine at room temperature gave dioxadithiocine tetroxide (147) (mp > 250°C) in 58% yield (Equation (35)) <90JOC2558>. 

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