Sulphinate salts oxidation

Nitronate salts have been shown to be oxidized to gem-dinitro-compounds by nitrite ion and persulphate in the presence of catalytic amounts of ferricyanide. gem-Cyanonitro- and a-nitro-sulphones were similarly obtained from reactions involving use of cyanide and sulphinate salts respectively. A 1,M-dinitro-compound... 

Whilst the sulphonic adds themselves cannot, in practice, he reduced, their sulphochlorides may he brought to a lower state of oxidation, that of the sulphinic acids, by treatment with metals, preferably with zinc. In this way the zinc salts of these acids are produced directly ... 

Bromine has been used for the preparation of copper salts of sulphonic acids, by oxidation of the corresponding sulphinic acid salts279. 

Oxidative amidation of sulphinic acids occurs under rather forcing conditions (18% oleum) to give a sulphonamide as product (equation 109)446. The severity of the reaction conditions means that this approach is not one that is generally applicable for the conversion. A far preferable method involves the rather mild oxidation of the ammonium salts of arenesulphinic acids with either hypochlorite ions or chlorine, in aqueous solution (equation 110)447. 

Iodine has also been used to oxidize sulphinic acids and their salts to sulphonyl iodides (equation 145)343,559,569- 572. Indeed, this was the first method by which alkanesulphonyl iodides were prepared and isolated571. 

Cahours independently discovered the sulphonium bases,but priority belongs to Adolf von Oefele, who found in Kolbe s laboratory that ethyl iodide combines with ethyl sulphide to form a compound similar to an ammonium salt, from which silver oxide formed the corresponding hydroxide. Von Oefele called the compound a sulfin (sulphine) and regarded the radical QH5I... 

In solution stable between pH 4-5 and 9-5 below pH 4-5 conversion to free Pyrithione which is very unstable in the presence of oxygen or light above pH 9-5 slow conversion to the sodium salt of Pyrithione sulphonic acid. Oxidizing agents such as peroxides and hypohalites will convert Pyrithione first to 2,2 -dithio-bis-pyridine-1,1 -dioxide (Section 11.1.5) and finally to inactive pyrithione sulphinic or sulphonic acid. 

Stable in mineral or acetic acid solutions (formation of soluble acid salts without cleavage of the sulphur-sulphur bond) in alkaline solutions slow cleavage of the disulphide linkage under release of the alkali salts of 2-mercaptopyridine-/V-oxide (see Section 11.1.3) and to a certain extent Pyrithione sulphinate... 

Lithium reagents desulphurize /ra s-2,3-diphenylthiiran 1-oxide, but give about equal yields of cis-stilbene and the lithium salt of stilbene-cf-sulphenic acid with cis-2,3-diphenylthiiran 1-oxide. Decomposition of the trans-isomer in the presence of ylides (53) leads to small yields of sulphines. Pyridine iV-oxide is deoxygenated by SO. In all these cases, kinetic measurements show that decomposition of the thiiran 1-oxide occurs independently of the substrate. 

Metal oxides have been employed to catalyse the acylation of aromatics, leading to dimethylbenzophenones and 4-substituted benzophenones. The reaction of t-butylbenzene with benzoyl chloride in the presence of small amounts of ferric oxide leads to 4-t-butylbenzophenone. Substituted benzophenones have also been obtained by hydrolysis of the dilithium salts (68) formed by the reaction of lithium carboxylates with organolithium derivatives, and benzo-phenone-2 -methoxy-2-sulphinic acids (69) have been successfully prepared by displacement of the sulphone linkage in thioxanthen-9-one 10,10-dioxides (70)... 

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