Disulphones rearrangement

The preparation of 2-naphthol by high-temperature sulphonation of naphthalene followed by alkali fusion of the resulting naphthalene-2-sulphonic acid has been mentioned previously. Further sulphonation of 2-naphthol yields several useful naphtholsulphonic acids and conditions can be chosen to make one or other of these compounds the main product. The initial product is the unstable 2-naphthol-l-sulphonic acid, which readily rearranges to 2-naphthol-6-sulphonic acid (4-36 Schaeffer s acid). Further sulphonation leads to 2-naphthol-6,8-disulphonic acid (4-37 G acid) at low temperature and 2-naphthol-3,6-disulphonic acid (4.38 R acid) at higher temperature. 

More recently, Sherk, Houpt and Brown decomposed phenyl azide in fuming sulphuric acid and isolated phenylhydroxylamine O,m-disulphonic acid (63) which, upon hydrolysis, rearranged to 4-aminophenol-2-sulphonic acid (64). The same product 64 (38%) was obtained in addition to -aminophenol (11%) on heating the azide in a 1 3 (v/v) mixture of sulphuric acid and water. 

The alkaline fusion of aryl 1,3-disulphonates and the acidic rearrangement of... 

The behaviour just discussed applies to the reactions of several classes of carbon acids, notably the removal of a proton from nitro- and keto-compounds, and the addition of a proton to aromatic systems. In all of these systems there is good evidence that the reaction is accompanied by a drastic electronic rearrangement, and it is of interest to enquire why some other classes of carbon acids, notably the cyano-compounds and the disulphones, behave quite differently. Some of these compounds are strong enough acids for their dissociation constants to be measurable in aqueous... 

Preparations.—a-Mercapto-a-amino-acids R NHCR (SH)C02H are obtained from corresponding chloro-compounds or from 4-chloro-oxazol-5(4H)-ones. Conventional methods are also used for synthesis of thio-resorcinols (from benzene-1,3-disulphonic acids via sulphonyl chlorides, reduced with red P-Ir-AcOH, or from resorcinols via Newman-Kwart rearrangement of O-dimethylaminothiocarbonyl-resorcinols followed by alkaline hydrolysis ). Dithiols are unexpectedly obtained from ethyl a-acetonylacetate by treatment with H2S in acid solution at -40 "C. Mercapto-ethylation of aliphatic amines is best achieved by a modificaticm of the well-established method using episulphides, in aqueous solution in the presence of a silver salt. Methyl sulphides ArSMe may be demethylated by chlorination to ArSCCh followed by acid methanolysis, while aryl diphenylmethyl sulphides are susceptible to electrolytic reduction to the thiophenol. ... 

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