Sulfinic acids sulfonyl chlorides

Similar halogenations have been done on 2-lithio-l-phenylsulfonylindole[2], 2-Lithio-l-phenylsulfonylindole is readily converted to the 2-(trimethylsilyl) derivative[2,3]. 2-Trialkylstannylindoles can also be prepared via 2-lithio-indoles[4,5], 2-Sulfonamido groups can be introduced by reaction of a 2-lithioindole with sulfur dioxide, followed by conversion of the sulfinic acid group to the sulfonyl chloride with A-chlorosuccinimide[6]. 

In the reaction between xanthates and sulfonyl chlorides, the xanthates convert to dixanthogens, and the sulfonyl chlorides reduce to sulfinic acids and other compounds (38) ... 

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. 

Sulfinyl chlorides may be prepared from the corresponding thiols or disulfides by oxidative reactions rather than by reductions of sulfonyl compounds. A recent example, which improves the earlier procedure of Douglass, is given by equation (3)50. The chemistry of sulfinic acids and their derivatives has been reviewed51 52,53. 

Sulfinic acids can be prepared by reduction of sulfonyl chlorides. Though mostly done on aromatic sulfonyl chlorides, the reaction has also been applied to alkyl compounds. Besides zinc, sodium sulfite, hydrazine, sodium sulfide, and other reducing agents have been used. For reduction of sulfonyl chlorides to thiols, see 19-57. 

Diazonium salts can be converted to sulfonyl chlorides by treatment with sulfur dioxide in the presence of cupric chloride. The use of FeS04 and copper metal instead of CUCI2 gives sulfinic acids (ArS02H). See also 13-18. 

The most commonly employed routes for the preparation of the / -sulfatoethylsulfone group, which is the essential structural feature of vinylsulfone reactive dyes, are illustrated in Scheme 8.5. One method of synthesis involves, initially, the reduction of an aromatic sulfonyl chloride, for example with sodium sulfite, to the corresponding sulfinic acid. Subsequent condensation with either 2-chloroethanol or ethylene oxide gives the / -hydroxyethylsulfone, which is converted into its sulfate ester by treatment with concentrated sulfuric acid at 20 30 °C. An alternative route involves treatment of an aromatic thiol with 2-chloroethanol or ethylene oxide to give the /Miydroxyethylsulfonyl compound which may then be converted by oxidation into the /Miydroxyethylsulfone. 

Cycloadditions to a cyano group are comparatively rare. The high-temperature reactions of 1,3-dienes, e.g. butadiene, isoprene and 2-chloro-l,3-butadiene, with dicyanogen, propionitrile or benzonitrile result in formation of pyridines (equation 80)70. Sulfonyl cyanides 147, obtained by the action of cyanogen chloride on sodium salts of sulfinic acids, add to dienes to give dihydropyridines 148, which are transformed into pyridines 149 by oxidation (equation 81)71. 

More abundant are reductions with sodium sulfite which is applied in aqueous solutions (solubility 24%). Its specialties are reduction of peroxides to alcohols [257], of sulfonyl chlorides to sulfinic acids [252], of aromatic diazonium compounds to hydrazines [253], and partial reduction of geminal polyhalides [254] Procedure 43, p. 216). 

Reduction of sulfonyl chlorides with Zn and acid yields first sulfinic acids and then thiophenols. C,H,SOXl > C H,SO H """ > C,H,SH... 

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. 

The crude -acetaminobenzene sulfonyl chloride (p. 3) obtained from 67.5 g. (0.5 mole) of acetanilide is shaken for two hours with a solution of 250 g. (1 mole) of crystallized sodium sulfite (Na2S03 7H2O) in 500 cc. of water. The reaction mixture is kept slightly alkaline by the addition at intervals of small portions of 50 per cent sodium hydroxide solution. The total volume of alkali used varies from 10 to 50 cc. After the alkaline mixture has been shaken for the two-hour period (Note 1) it is filtered, and the filtrate is acidified with 60 per cent sulfuric acid. If the acid is added slowly, the sulfinic acid comes down in fine crystals which after filtering and drying, melt at 1550 with decomposition (Note 2). The yield is 50-55 g. (43-47 per cent of the theoretical amount based on the acetanilide used). 

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,... 

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