Sulphonyl halides—

Full details of the use of mesitylenesulphonyl chloride as a selective sulphonyl-ation reagent for carbohydrates have been published.  

Chlorinolysis of pyrazole-4-sulphonyl chlorides with Cla in aqueous AcOH causes displacement of the chlorosulphonyl group and cleavage of the ring.  

Sulphonates.—Synthesis of aryl arenesulphonates through arenesulphonoxylation of unactivated aromatic hydrocarbons can be accomplished using arenesulphonyl peroxides. Although other serviceable routes to sulphonate esters do not need to be documented here, since they are so well known, a procedure for the 

Elimination reactions of aryl arylmethanesulphonates leading to phenyl-sulphenes have been shown to involve E ch characteristics where the leaving group is a phenol with pJlTa less than 6, otherwise a concerted E2 mechanism applies. 

Hammett and Taft substituent constants have been determined for mesylate, tosylate, and triflate groups.  

Routine mechanistic studies (solvolysis of PhCHjSOjCl and of ArSOjCl or ArSOjBr aminolysis of arenesulphonyl chlorides and of toluene-p-sulphonyl bromide, catalysed by imidazole and the reaction of ArSOjCl with phenols ) have been reported. 

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In 1968 the Monsanto Company announced the availability of novel soluble low molecular weight polyphenylene resins. These may be used to impregnate asbestos or carbon fibre and then cross-linked to produce heat-resistant laminates. The basic patent (BP 1037111) indicates that these resins are prepared by heating aromatic sulphonyl halides (e.g. benzene-1,3-disulphonyl dichloride) with aromatic compounds having replaceable nuclear hydrogen (e.g. bisphenoxy-benzenes, sexiphenyl and diphenyl ether). Copper halides are effective catalysts. The molecular weight is limited initially by a deficiency in one component. This is added later with further catalyst to cure the polymer. 

One approach by Monsanto (described in the basic patent BP 1037111) is to prepare a modified polypenylene by reacting an aromatic sulphonyl halide such as benzene-1,3-disulphonyl dichloride with an aromatic compound having replaceable nuclear hydrogen (e.g. bisphenoxybenzene, sexiphenyl and diphenyl ether). This was discussed in Chapter 21. 

A few studies are reported which describe the direct oxidation of sulphoxides to sulphonic acids, sulphonyl halides, thiosulphonates and sulphate. These reactions will be considered in this section but it should be noted that they are rarely of synthetic utility. 

Acyl and sulphonyl halides, a-halogeno-ethers and alkyl iodides react rapidly. 

An important feature of reactions in solvent mixtures is the effect of substituents in the reactant on the kinetic parameters. As Foon and Hambly (1962) note with reference to the hydrolysis of a series of sulphonyl halides, it is possible to obtain almost any order for the rate constants by selection of the appropriate solvent mixture. The substituent effects also depend on the temperature and, in the case of bimolecular reactions, on the nature of the attacking group, e.g. OH- instead of H20 (Tommila, 1967). 

The reaction with acyl or sulphonyl halides, however, can take two further paths, either ring-contraction to give the isoquinoline A -imide hydrochloride (69) or via dimerization of the short-lived dehydrochlorinated species (68)." ... 

Despite the interest in, and importance of, sulphonic acids and their salts, osylates and other sulphonate esters, sulphonamides, sulphonyl halides and miscellaneous derivatives such as disulphones, thermochemical data for this class of compounds are disappointingly sparse and often suspect. Thus the data will not be presented in the form of tables, but rather will be discussed one primary reference at a time per subsection. Because the required gas phase data are almost totally absent, we will also not attempt to generate Benson increments1 for groups of interest such as S02(C)(0), as would be part of a thermochemical study of sulphonic acids and their esters but not the isomeric sulphites that contain the SO(0)2 group. As such, this chapter is unlike so many of the other thermochemical chapters in the other volumes of The Chemistry of the Functional Groups series. 

Carboxylic acid anhydrides have been determined via estimation of the water consumed in an analogous reaction but only two examples could be found for a sulphonyl halide, namely p-acetylaminobenzenesulphonyl chloride, where excess water was back-titrated with the Karl Fischer reagent245,246. 

A gasometric determination or titration of unused oxalic acid was performed. The author observed gas evolution also with sulphonyl halides, but this was not pursued further. 

The products of hydrolysis of sulphonyl halides, i.e. sulphonic and hydrohalic acids, can be easily titrated with bases, which accelerate the hydrolysis as well. Thus Cundiff and Markunas titrated potentiometrically benzenesulphonyl chloride (and sulphuric acid) in pyridine with tetrabutylammonium hydroxide in benzene/methanol251. Jansseune and Janssen252 titrated sulphonyl fluorides in butylamine with potassium methoxide. Krivoruchko253 estimated 2-chloroethanesulphonyl chloride in air by hydrolysing it with alcoholic potassium hydroxide and determining the chloride ion colorimetrically or nephelometrically. Jansseune and Janssen252 also hydrolysed sulphonyl fluorides with alkali, acidified the mixture, distilled the HF and titrated it with alkali. 

The difference between the alkali titrations in the two cases corresponds to the ester formed and hence to the original anhydride. Free-acid impurities are equal in the two cases and cancel out in the difference. In principle, this method should be applicable to sulphonyl halides and anhydrides but no example could be found in the literature. 

Ammonia or primary or secondary amines have been used instead of alcohols in the differential procedures. Only two examples of application to a sulphonyl halide could be found Klamann256 used aniline to determine p-toluenesulphonyl chloride, titrating with NaOH. Recently Spince, Luse and collaborators260,261 determined aromatic sulphonyl chlorides using aniline or a-naphthylamine in DMF or DMSO, titrating with KOH. 

As an alternative to the differential procedure a measured amount of excess amine has been used to determine acid anhydrides, unused amine then being back-titrated. Aniline and nitro- or halogeno-substituted anilines have been used, but only two examples could be found of application to sulphonyl halides Terent ev and coworkers used hexamethy-leneimine in methanol, then back-titrated with HCl/methanol262 and Allan and Sobodacha263 used 3-chloroaniline in l-methyl-2-pyrrolidone and back-titrated with standard NaN02. 

A recent method for determining carboxylic or sulphonyl halides depends on reaction in acetone/water with excess sodium azide. Unconsumed azide is then determined by... 

Sulphonyl halides (excluding the fluorides) can be reduced to sulphinate ... 

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