Thiosulfonic Esters

Thiosulfonates may be thermally labile in the sample introduction system of a mass spectrometer, so that care must be exercised to ascertain the ionic, rather than the thermal, origin of fragment ions in their mass spectra. 

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. 

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The treatment of diaryl disulfides with BTIB in dichloromethane leads to the production of S-aryl thiosulfonic esters 7 (Scheme 4) [18]. When such reactions are conducted in an alcoholic medium, arenesulfinic esters 8 are obtained [19]. Similar conversions of arenethiols to 7 or 8 with BTIB can also be effected [18,19]. 

In laboratory work the oxidation of disulfides has been applied particularly to the preparation of thiosulfinic and thiosulfonic esters ... 

Oxidation to thiosulfinic esters is best effected by an equivalent amount of perbenzoic acid or peracetic acid in chloroform,594 and the preparation of thiosulfonic esters by a slight excess of hydrogen peroxide in acetic acid or by chlorine in the presence of glacial acetic acid with subsequent treatment by water.595-597... 

Alkyl thiosulfonate esters apparently undergo nucleophilic attack by phosphite on sulfur rather than on carbon, forming 0,0,8-trialkylphos-phorothioates and alkyl esters of sulfinic acids (223,227). 

In the presence of excess phosphite, the disulfide reacts further (see Section V-A-2), furnishing the products expected (see eq. 10). Thiosulfonate esters fail to react with triaryl phosphites even at 180 . 

Typically, the dithionite species disproportionates in aqueous media to afford the hydrogen sulfite and thiosulfonate nucleophiles.64 This finding suggests that sulfite esters (-0S02 ) and Bunte salts (-SS03-)65 could be formed upon iminium methide... 

Sulfenyl chlorides react with zincalkyl (or -aryl) sulfinates and also with sodium benzene sulfinate to yield the corresponding esters of thiosulfonic acid 13, 111, 161) ... 

Disulfides, diselenides, and ditellurides can be oxidized by hypervalent iodine compounds quite easily. Depending on the reaction conditions disulfides can be oxidized to sulfinic esters [59] or thiosulfonic S-esters [60,61]. Diselenides can be transformed into selenosulfonates [62]. Arenetellurinic mixed anhydrides are mild oxidants and can be obtained by oxidation of the corresponding ditellurides as shown in Scheme 9 [63]. Recently it was shown that a thioacetal based linker for solid-phase synthesis can be cleaved oxidatively using [bis(trifluoro-acetoxy)iodo]benzene 4 [64]. 

Such sulfinate compounds are water soluble and may be used as antiradiation drugs (see Section 7.4). Bis(sulfinato)trisulfanes may be converted to the corresponding bisalkyl esters by reaction with either diazomethane or a solution of BF3 in diethyl ether. When sodium polysulfide is apphed in equation (59) the resulting poly-sulfanes (equation 60) contain up to six sulfur atoms. However, bis(sulfinato)polysulfanes with more than four catenated sulfur atoms are unstable in water, and elemental sulfur is slowly precipitated. When the thiosulfonate RS(0)-(CH2)2-SS02C6H4Me was used in equations (59) and (60), the bis(sulfoxido)trisulfane [RS(0)-(CH2)2]2S3 resulted. ... 

Thiosulfonic S-esters. L sodium triflate is added, RSTf i lodination. Efficient at and heteroarenes by PhI(OCOC Nucleophilic aromatic suh alkoxyarenes generates electro MejSiNj and 1,3-diketones. 

Acid chlorides undergo ptutial reduction by Zn and the in situ capture forms enol esters, whereas sulfonyl chlorides give thiosulfonic 5 -esters when they are treated with Zn in EtOAc. The presence of AcCl is critical. 

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>. 

The reaction described above has been successfully applied to the preparation of various symmetrical thiosulfonic S-esters (Table).10 The procedure described here gives better and more reproducible results than the one reported before.10... 

The preparation of sulfinic acids by fission of the S-S bond of thiosulfonic salts or esters is useful when other methods are excluded by the presence of sensitive substituents. Arenethiosulfonic acid salts, which are formed from arenesulfonyl chlorides and alkali sulfides ... 

S-Alkylthiosulfates S-Arylthiosulfates Sulfinylsulfones Thiosulfuric acids and esters Thiosulfonic acids 5... 

Sulfurization of tricoordinated phosphorus compounds by treatment with 3H-1,2-benzodithiol-3-one 1,1-dioxide results from the nucleophilic attack of, for example, a phosphite triester on the electrophilic thiosulfonate function of 2 to produce the phos-phonium sulfinate intermediate 3 (eq 2). Intramolecular condensation of the sulfinate anion with the carbonyl group of the activated thiol ester function releases the phosphorothioate triester (4) with concomitant formation of 5. Because of the... 

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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