Reactions of some 2-aminophenyl- and 2- and 4-nitrophenyl sulfones in aqueous sodium hydroxide solution

When 2-aminophenylsulfonylacetic acid (3) was heated under reflux in an excess of dilute sodium hydroxide solution, the only product identified was 2-methylsulfonylaniline (6). When 2-nitrophenyl-sulfonylacetic acid was treated under the same conditions, the major products identified were 2-methyl-sulfonylnitrobenzene (7), 2-nitrophenol (8), and orthanilic acid (13); minor products of this reaction were 6 and 3-methylsulfonyl-3′-nitro-4-amino-4′-hydroxybiphenyl (12). The same products were obtained although the yields were different when 7 was boiled with alkali, but the reaction of 4-methylsulfonyl-nitrobenzene (15) with alkali was less complex and 4-nitrophenol (16) was the only major product. The biphenyl 12 was also formed in small yield when N-(2-methylsulfonylphenyl)hydroxylamine (19) was treated with alkali and its formation in these reactions was investigated in detail. It was concluded that 12 arises from 7 and 19, but it could also be prepared from 19 and 2-chloro- or better, 2-fluoronitrobenzene, in alkaline solution, and based on all these observations, a mechanism for its formation is suggested. The genesis of the various other products is also discussed. Reference is made to the infrared spectra of sulfones.