Aromatic sulphonyl chlorides

The reduction by Cu(I) in acetonitrile at 110 °C in the presence of styrene was followed dilatometrically The mechanism given is 

Initiation C6H5CH-CH2 + 2 CuClz - QH5CHCICH2CI + 2 CuCl (fast) 

ArS02CH2 HC6H5 + CuCl2 ArS02CH2CHClC6H 5 + CuCl (fast) 

Application of stationary state treatment for ArS02 and ArS02CH2CHCgHs produces a complex rate law which reduces at low Cu(II) concentrations to 

This is adhered to experimentally and for Ar-CgHs, IC2 = 0.0893 l.mole sec under the conditions specified. Results for a set of ring-substituted analogues give a good Hammett plot with p = -1-0.565. Certain aspects of this system remain unclear, e.g. the non-appearance of polymer at very low Cu(II) concentrations and the exact nature of the Cu(I) species. 

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COVALENT COMPOUNDS, METAL IONS OXIDATION-REDUCTION 6.4.12 Aromatic sulphonyl chlorides... 

A comprehensive study of the reducing properties of phosphine particularly with respect to aromatic nitro-compounds and aromatic sulphonyl chlorides, was published by Buckler et al. 

The presence of a second tertiary amine group can result in further complications owing to competition with the neighbouring enamine function for the electrophilic sulphene204 (Scheme 88). Aromatic sulphonyl chlorides cannot form sulphenes and hence give the acyclic sulphone205-207 (Scheme 89). 

O. Rogne, The Kinetics and Mechanism of the Reactions of Aromatic Sulphonyl Chlorides with Anilines in Methanol Bronsted and Hammett Correlations, J. Chem. Soc. B, 1971, 1855. 

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. 

Aromatic sulphonyl chlorides are among the tested compounds in some colorimetric methods for determining nerve gases . Thus Marsh and Neale271 used o-dianisidine/H202 and Gehauf and coworkers272 used benzidine/sodium perborate. A possible initial reaction is... 

Polarographic reduction of sulphonyl chlorides is evidently also a two-electron process, yielding sulphinate and chloride. Work in this domain has not been analytical, however. An indirect method for determining aromatic sulphonyl chlorides in DMSO has been based on H+ and/or Cl" waves278. 

Alkoxide anions also react with sulphonyl halides to produce a good yield of the corresponding sulphonate ester, as shown in equation 83. Both alkali metal360,376,377 and thallium(I)378 alkoxides have been employed and the latter reagent produces nearly quantitative yields when mixed with an aromatic sulphonyl chloride. It has been shown that higher yields of the sulphonate ester are realized as the metal counter-ion size increases379. 

Although rarely of synthetic value, aromatic sulphonyl chlorides may be prepared by... 

Aromatic sulphonyl chlorides may be prepared, in excellent yields, by the oxidation of a thiocarbamic ester (a masked thiol), after initial Newman-Kwart rearrangement597, as shown in equation 151. The latter is readily prepared from phenols. 

Aromatic sulphonyl chlorides have been synthesized from unsubstituted sulphona-mides by reaction with PC15639. On the other hand, AT-alkyl substituted sulphonamides undergo a rather surprising reaction with the same reagent, as shown in equation 160640. Sulphonyl fluorides may be prepared from unsubstituted sulphonamides by reaction of the latter with HF and sodium nitrite641. 

The difference of reactivity between neutral and acidic solvents could only lie in the fact that the aromatic sulphonyl chloride is protonated and consequently reduced more easily in its protonated form. A potential shift of about 0.5 V for the main reduction step (Figure 10b) can be observed in the voltammetries. The general Scheme 951 fits the two possible routes according to the acidity of the medium. 

The rates of oxidation of cuprous chloride by a range of aromatic sulphonyl chlorides have been derived. The reaction ... 

As an aromatic sulphonyl chloride, Dns-Cl reacts with primary and secondary amino groups even at slightly alkaline pH it reacts at higher pH with phenols, imidazoles, and even slowly with alcohols. Derivatives with barbiturates, purines and carbamates are also known. Thiol compounds form the corresponding disulphides [7, 17]. 

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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