Ethyl thiosulfonate

In soft cheeses, such as Brie, Camembert, and Limburger, the following sulfur compounds were implicated 3-(methylthio)propanol, MT, DMS, DMDS, DMTS, dimethyl tetrasulfide, methyl ethyl disulfide, diethyl disulfide, 2,4-dithiapentane, 3-methylthio-2,4-dithiapentane, methional, 2,4,5-trithiahex-ane, 1,1-fe-methylmercaptodisulfide, methyl thioacetate (=methanethiol acetate), benzothiazole, methylthiobenzothiazole, methyl ethyl sulfonate, methyl methane thiosulfonate, thiophene 2-aldehyde, and H2S.34 Many of these were only present in small amounts Limburger cheese was notable for 13.2% of DMDS, 0.5% of methyl thioacetate, and 0.8% of DMTS. 

Use of thiirane 1,1-dioxide affords a useful synthesis of ethanesulfinates with the following functions in the 2-position thiol, disulfide, trisulfide, thiosulfate, thiosulfonate, and phos-phorthioate. Reaction of episulfone (83) with sodium p-toluenethiolate gives the sulfinate (84), which can be converted to the sulfone (85) (Scheme 35). Similarly, (83) is converted to the benzyl counterpart (86), which is desired for possible debenzylation to the thiol since the salt (86) is difficult to purify, it is converted to the ethyl ester (87) <86JOC5235>. 

Corina and coworkers65 gave the El mass spectra of two fluorinated ethyl methane-thiosulfonates (95 and 96), which showed distinct molecular ions and preferential S—S bond cleavage, in analogy with unsubstituted 93a. However, the extent of fluorine substitution affected the site of charge retention, so that base peaks at m/z 78, [CH2FCHS]+, and m/z 79, [MeS02]+, were found for 95 and 96, respectively. 

Synthesis of Sulfinate Ester. 5-Ethyl ethanethiosulfinate can be transformed to the stable sulfinate esters by replacement of the sulfenyl group with catalytic bromine and H2 O2 in the presence of an alcohol such as Isopropanol (eq 11). However, in absence of the alcohol, the thiosulfinate disproportionates rapidly under these conditions and forms a mixture of thiosulfonate and disulfide. 

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