Sulfinic acid chlorides sulfones

Sulfinic acids from sulfonic acid chlorides... 

Thiophene-2-sulfonic acid is a strong acid, similar to benzenesulfonic acid. It forms a sulfonyl chloride with phosphoryl chloride which on reduction with zinc yields thiophene-2-sulfinic acid. 

These acids are less stable, less soluble and less acidic than the corresponding sulfonic acids. The common impurities are the respective sulfonyl chlorides from which they have been prepared, and the thiolsulfonates (neutral) and sulfonic acids into which they decompose. The first two of these can be removed by solvent extraction from an alkaline solution of the acid. On acidification of an alkaline solution, the sulfinic acid crystallises out leaving the sulfonic acid behind. The lower molecular weight members are isolated as their metal (e.g. ferric) salts, but the higher members can be crystallised from water (made slightly acidic), or alcohol. 

Sulfenyl cldorides, sulfinic acids and sulfinyl chlorides were reduced in good yields by lithium aluminum hydride to disulfides [680], The same products were obtained from sodium or lithium salts of sulfinic acids on treatment with sodium hypophosphite or ethyl hypophosphite [507]. Sulfoxy-sulfones are intermediates in the latter reaction [507]. 

Chlorides of sulfonic acids can be reduced either partially to sulfinic acids, or completely to thiols. Both reductions are accomplished in high yields with lithium aluminum hydride. An inverse addition technique at a temperature of —20° is used for the preparation of sulfinic acids, while the preparation of thiols is carried out at the boiling point of ether [69S]. 

The sulfonic acids of these metallocenes can be converted to sulfonyl chlorides, sulfonamides, etc., by appropriate reagents. Reduction of ferrocene-sulfonyl chloride by lithium aluminum hydride produces the rapidly oxidized ferrocenethiol in quantitative yield (43). Both the sulfonic acid of cyclopentadienylmanganese tricarbonyl and the corresponding sulfinic acid (obtained by sodium sulfite reduction of the sulfonic acid) have been converted to sulfones (10). 

Thiols can be prepared by the reduction of sulfonyl halides652 with LiAIH4. Usually, the reaction is carried out on aromatic sulfonyl chlorides. Zinc and acetic acid, and HI. also give the reduction. Sulfonic acids have been reduced to thiols with a mixture of triphenyl-phosphine and either Ii or a diaryl disulfide.633 Disulfides RSSR can also be produced.634 For the reduction of sulfonyl chlorides to sulfinic acids, see 0-118. 

Buffer catalysis of the hydrolysis of phenyl (311 R = Ph) and methyl (311 R = Me) benzenesulfinates to give the sulfinic acid (312) and alcohol ROH is strongly accelerated by both carboxylate and amine components of the buffer which give Bronsted /i values of approximately unity on separate lines. The carboxylates are about 44 tunes more effective than amines of similar basicity. A concerted. S n2 mechanism with a hypervalent intermediate (313) is proposed for the nucleophilic reaction of these esters.286 The reaction of the thiosulfinate esters (314) with sulfenyl chlorides RSCI and sulfenate esters (315) to give sulfinyl chlorides and disulfides and sulfinate esters and disulfides, respectively, has been studied.287 Hydrolysis of 2-(3-aminophenyl)sulfonyl-ethanol hydrogensulfate gives under different conditions various products such as the ether (316) and the sulfone (317).288... 

Thiazolyl sulfamic acids, rearrangement of sulfonic acid, 70 rearrangement to sulfonic acid, 75 by sulfonation, 75 2-Thiazolyl sulfenyl chloride, transformation to, thiazolyl disulfides. 412 2-Thiazolyl sulfide, in hydrocarbon synthesis, 406 oxidation of, with m-chloroperbenzoic acid, 415 with CrOj, 415 with Hj02,405,415 with KMn04,415 physical properties, infrared, 405 NMR, 404 pKa, 404 ultraviolet, 404 preparation of, from 2-halothiazoles and 5-Thiazolyl sulfides, bis-5-thiazolyl sulfide, oxidation of, 415 general, 418 5-(2-hydroxythiazolyl)phenyl sulfide case, 418 physical properties, 418 preparation of, 417-418 table of compounds, 493-496 uses of. 442 2-Thiazolyl sulfinic acid, decomposition of, 413 preparation of, from 2-acetamidothiazole sulfonyl chloride, 413 from A-4-thiazoline-2-thione and H, 0, 393,413 table of compounds, 472-473 5-Thiazolyl sulfinic add, preparation of,... 

Arylsulfonyl chlorides are pivotal precursors for the preparation of many diverse functional types including sulfonate esters,8 amides,4 sulfones,9 sulfinic acids,10 and others.11 Furthermore, sulfonyl fluorides are best prepared from sulfonyl chlorides.12 The sulfonyl fluorides have many uses, among which is their utilization as active site probes of chymotrypsin and other esterases.13 The trifluoromethyl group also plays valuable roles in medicinal chemistry.14... 

Sulfinic acids and sulfoxides are not particularly common, being readily oxidized to the sulfonic acids and sulfones, respectively. Sulfonic acids have high melting points and probably exist as zwitterions. They are amphoteric, but mainly display the characteristics of weak acids. The sulfonic acid group activates an adjacent halogen to nucleophilic displacement, and may itself be displaced, e.g. reaction of alkylamines with benzimidazole-2-sulfonic acid. Imidazolesulfonic acids resist esterification and acid chloride formation, and are only hydrolyzed by concentrated hydrochloric acid at 170 °C the 2-isomers are more resistant than the 4- or 5-isomers. Aqueous alkali converts the free acids into hydroxy derivatives. Sulfonyl chlorides are accessible via the thiols (Section 4.07.3.6.1) which react with ammonia to form sulfonamides, or are reduced by tin(II) chloride to thiols (77JHC889). 

Sulfonic acids and sulfonyl chlorides can also be prepared from sulfinic acids by oxidation with sodium permanganate (equation 590) [556] and chlorine in water (equation 591) [656], respectively. 

Sulfinic acids react easily with alkyl or benzyl halides to give the corresponding sulfones, e.g. (8), and (9) (Scheme 7). Sulfinic acids react similarly with sulfenyl, sulfinyl and sulfonyl chlorides to give thiolsulfonates (10), sulfinyl sulfones (11) and disulfones (12), respectively (Scheme 8). 

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