Thiosulphinates

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. 

Unsymmetrical thiosulphinates and thiosulphonates are both oxidized by potassium superoxide in pyridine in the presence of 18-crown-6 ether to produce sulphinic and sulphonic acids and a disulphide, under mild conditions (equation 84)200,201. Sulphinic and sulphonic acids were produced from both the R and R substituents whilst the disulphide was derived only from the sulphenyl side of the reactant. Thus, the reaction mixture contained five products, making the reaction not synthetically useful. Pyrolysis of thiosulphinates also produces mixtures of products, one being the thiosulphonate again this is not a synthetically useful reaction202. 

Electrochemical oxidation of thiosulphinates leads cleanly to the corresponding thiosulphonate in reasonable yields with no observed side-products203. 

Sulphinates 60-70 - see also Alkanesulphinates, Arenesulphinates, Thiosulphinates ally - see Allyl sulphinates chiral - see Chiral sulphinates photolysis of 1076... 

Other compounds containing heteroatom-heteroatom bonds have been reported as 5-LO inhibitors. Diphenyldisulphides and substituted analogues, as well as disulphiram (108), inhibited cRBL and LT release from zymosan-stimulated mouse macrophages (0.3-20 / M) [277, 278]. A number of thiosulphinate esters such as (109) and related compounds, isolated from onion and garlic, were likewise active in cells and cell-free enzymes over the... 

Organosulphur compounds, e.g., S-methyl cysteine sulphoxide (SMCSO) and its metabolite methyl methane thiosulphinate, both naturally occurring compounds present in Brassica vegetables (broccoli, cabbage) were found to inhibit benzo[a]pyrene-induced micronucleus formation in mouse bone marrow by 31 and 33%, respectively, after oral administration (Marks et al. 1993). 

Marks HS, Anderson JA, Stoewsand GS. 1993. Effect of S-methyl cysteine sulphoxide and its metabolite methyl methane thiosulphinate, both occuring naturally in brassica vegetables, on mouse genotoxicity. Food Chem Toxic 31 (7) 491-495. 

Drugs with Cysteine sulphoxides and Thiosulphinates Allium sativum L Allium ursinum L, Allium cepa L. - Alliaceae... 

Allium sativum and Allium ursinum preparations show a very similar qualitative composition of sulphur-containing compounds. Quantitative diiTerences are knovm for alliin/allicin and other cysteine sulphoxides and thiosulphinates, respectively. 

Allicin is absent in Allium cepa preparations. Onions contain cepaenes and different thiosulphinates in comparLson to garlic and wild garlic. 

Fi eshly prepared extracts of Allium cepa (3) show five to seven dark-brown zones in the RI range 0.2-0.65 with two prominent zones of thiosulphinates at R, 0.3 and R, - 0.45. The dipropylthiosulphinate (T3) at R, 0.45 is the characteristic compound of onion extracts. Allicin with almost the same R, value is absent. Other thiosulphinates such as dimelhylthio.sulphinate (T4) at Rf 0.2 are present, which in contrast to garlic thiosulphinates (TS) show brown to brown-red colours (vis.), This is partly due to higher TS concentrations and to compound.s which overlap the TS, as. shown in Fig. 6. 

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