Sulphur dioxide sulphonyl chlorides

When polyethylene is chlorinated in the presence of sulphur dioxide, sulphonyl chloride as well as chlorine groups may be incorporated into the polymer Figure 10.10). This reaction is used to produce a useful elastomer (Hypalon, see Chapter 11). 

Steroidal ii -alcohols do not form sulphonate esters, but have been converted into -olefins by reaction with methane sulphonyl chloride in the presence of sulphur dioxide... 

Sulphonyl halides, mainly the chlorides, may be prepared using halosulphonic acids, sulphur dioxide and sulphuryl halides as the most important sources of sulphur. These preparative methods are discussed below. 

Aromatic diazonium salts react with sulphur dioxide, either in the liquid state or mixed with an organic solvent, such as acetic acid, in the presence of copper(II) chloride to give 50-90% yields of sulphonyl halides205,527-529 (equation 138). Nitrogen is evolved during the reaction and higher yields are usually obtained in the presence of a solvent. 

Sulphonyl chlorides may be obtained by the reaction of some aliphatic compounds with a mixture of sulphur dioxide and chlorine, under conditions which permit the formation of radicals (equation 139)299,530-533. Usually a mixture of products is formed with amounts of each product being determined by the stabilities of the intermediate alkyl radicals. Thermodynamic or kinetic control of products may be exercized by control of the reaction temperature. 

Sulphinate salts, obtained by reaction of sulphur dioxide with either alkyllithiums or Grignard reagents, are converted into sulphonyl chlorides upon reaction with sulphuryl chloride582, as shown in equation 149. The same reaction occurs if thionyl chloride dissolved in DMF is used583. 

It may be prepared by the diazotization and subsequent treatment with sulphur dioxide in glacial acetic acid in the presence of cupric chloride of 3-amino-4-chloro-benzophenone-2-carboxylic acid to yield 4-chloro-2 -carboxy-benzophenone-3-sulphonyl chloride. This on treatment with thionyl chloride followed by amidation in aqueous ethanol and finally with HCl gives crude chlortalidone which is recrystallized from aqeous ethanol. 

Attempts to prepare derivatives of sulphur(iv) or sulphur(vi) by the reaction of thionyl or sulphonyl chloride with lead thiolate failed, as the sulphur(ii) derivative and sulphur dioxide were formed ... 

Diazotization. Diazonium salts of benzothiazoles have been useful in interconversions involving amino-derivatives of this ring system. 2-Fluoro-benzothiazoles are accessible by the diazotization of the corresponding 2-amino-compounds, followed by cautious pyrolysis of the isolated diazonium fluoroborate with potassium fluoride and sand under reduced pressure. The four isomeric sulphonic acids of 2-methylbenzothiazoles are obtainable from the amino-compounds by diazotization, followed by treatment with acetic acid saturated with sulphur dioxide in the presence of cupric chloride the resulting sulphonyl chlorides serve as source of the... 

Pyridine-2- and -4-sulphonyl chlorides are unstable compounds, which are said to decompose above 0° to give sulphur dioxide and the chloropyridines . Pyridine-3-sulphonyl chloride is stable as its hydrochloride . All three isomers readily give amides. 

Pyridine-3-sulphonyl chloride is reduced to the thiol by stannous chloride s and to the disulphide by sulphur dioxide and hydriodic acid s . With hydrazine hydrate in diethylene glycol, the pyridinesulphonyl chlorides give the disulphides S 2, and with zinc and water, pyridine-2-sulphonyl chlorides yield the sulphinic acids s ... 

In the preparation of chlorosulphonated polyethylene the polymer (commonly, a low density polyethylene with molecular weight (M ) of about 20000) is treated with chlorine in the presence of a small amount of sulphur dioxide. Typically, the reaction is carried out in solution in hot carbon tetrachloride. Both chloride and sulphonyl chloride groups are introduced into the polymer, the degree of substitution and the ratio of the two types of groups depending on the reaction conditions. Commercial products generally contain about 30% chlorine and 1.5% sulphur, which corresponds to approximately one chlorine group per 7 carbon atoms and one sulphonyl... 

Reaction at Sulphur.—The oxidation of benzo[6]thiophens to sulphoxides by t-butyl hypochlorite has been studied. In the presence of a ruthenium catalyst, dibenzothiophen was oxidized by oxygen to the sulphone. The reactions of benzo[ >]thiophen 1,1-dioxides with various reagents such as amines, amino-alcohols,3-aminopropylsilanes, and aromatic sulphonyl chlorides have been studied. Four detailed papers on the reaction of dibenzophenonium salts with aryl-lithiums have appeared in which the mechanism of ligand exchange was elucidated. " ... 

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