Disulphoxides

Racemic or optically active /J-disulphoxides can be obtained via a facile one-step procedure from arenesulphinic esters and a-sulphinyl carbanions558 or by oxidation of a-sulphinyl carbanions559. 

Filgueiras and coworkers222 prepared the complex of a disulphoxide with triphenyltin chloride. The complex is a 2 1 adduct with two Ph3SnCl units whose Sn atoms occupy the centre of the two trigonal bipyramids, as shown in Scheme 17. 

Thiosulphinates are derivatives of disulphides with one of the sulphur atoms at the sulphoxide oxidation level. In theory, oxidation of a thiosulphinate could produce two products, a disulphoxide and a thiosulphonate (equation 79). Discussions of this topic have been very polarised over the years but now it is fairly well established that the thiosulphonate is the major product formed in most cases, although the intermediacy of a a-disulphoxides is indicated from some data. 

The reaction mechanism for the peracid oxidation of thiosulphinates is perhaps more complex than described above. A study of the low-temperature ( — 40 °C) peracetic acid oxidation of 2-methyl-2-propyl 2-methyl-2-propanethiosulphinate gave two products as shown in equation (81)196. During the reaction the a-disulphoxide was apparently detected by NMR spectroscopy. 

Sulphonylthioureas, mass spectra of 158 Sulphoxides - see also Alkoxysulphoxides, Aminosulphoxides, -Anilinosulphoxides, Cyanosulphoxides, a, /i-Dihalosulphoxides, Disulphoxides, Enaminosulphoxides, Episulphoxides, Epoxysulphoxides, Halosulphoxides, Hydroxysulphoxides, /i-Iminosulphoxides, Ketosulphoxides, a-Lithiosulphoxides, /i-Oximinosulphoxides, Persulphoxides, a-Thioamidosulphoxides addition reaction of 619-623, 836-845 aliphatic - see Aliphatic sulphoxides alkenyl - see Alkenyl sulphoxides alkyl aryl - see Alkyl aryl sulphoxides /(-alkylthio(arylthio)ethyl - see /J-Alkylthio(arylthio)ethyl sulphoxides... 

Thiosulphonate structure (a) is expected to give two peaks of equal intensity corresponding to the two oxidation states in the molecule whereas the disulphoxide structure should give only one peak. ESCA spectrum shows that the thiosulphonate structure applies to the doubly oxidised cystine because two peaks of equal intensity is observed. 

L-Cystine [56-89-3] M 240.3, [oc]d -229° (c 0.92 in M HCI). Cystine disulphoxide was removed by treating an aqueous suspension with H2S. The cystine was filtered off, washed with distilled water and dried at 100° under vacuum over P2O5. Crystd by dissolving in 1.5M HCI, then adjusting to neutral pH with ammonia. Likely impurities are D-cystine, meso-cystine and tyrosine. 

Oxidizing agents Halogens Oxidize thiol groups to disulphides, sulphox-ides or disulphoxides... 

Ab initio MO calculations at the 6-31G level verify these conclusions and reveal that (i) disproportionation of arenesulphinyl radicals to arenesulphonyl and arenethiyl radicals is exothermic by —13.6kcalmol-1 and (ii) that the sulphenyl sulphinate structure 57 is 28kcalmol 1 more stable than the wc-disulphoxide 58108. 

The macrocycles (14)2 and (15) containing the phosphine oxide function have been prepared. Oxidation of (15) produces only the d,/-form (16) of the disulphoxide. This differs from the corresponding oxidation of the acyclic analogue (17) which gives all four possible stereoisomers of (18). It is suggested that the selective formation of (16) is due to the... 

SO3 reacts with Na2B407 at 190—200 °C to give a mixed oxide B203,2S03 (boron disulphoxide) and a mixture of Na2B4(S04)7 and Na2B20(S04)3. ... 

The disulphoxides generally are not isolated but are decomposed with sodium hydroxide to the ketone . The reaction works well in the steroids, with 17/3-acetoxytestosterone (3) easily being regenerated from its dithio-acetal (equation 13). 

The use of a mild oxidizing agent such as 1-chlorobenzotriazole with 1,3-dithiolanes and 1,3-dithianes leads to the formation of disulphoxides. 

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