Sulfinic from sulfonyl chlorides

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... 

Sulfonyl cyanides. The compounds can be prepared from sulfonyl chlorides by reduction to sodium sulfinates followed by reaction with cyanogen chloride. Example ... 

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. 

Whereas sulfonyl halides have been known for a long time and, especially the chlorides, have become of great synthetic value, sulfonyl cyanides were unknown until 1968. They were first prepared by van Leusen and co-workers from the reaction of sulfonylmethylenephos-phoranes with nitrosyl chloride. The same group also investigated part of their chemistry. Since then, two more, completely different, methods of synthesis were published from sulfinates with cyanogen chloride,and by the oxidation of thiocyanates. ... 

Some sulfinates are commercially available. They may be used as starting materials for the preparation of sulfonyl cyanides also. Yields, however, are not significantly better than when the much cheaper and more readily available sulfonyl chlorides are used as starting materials. Good to excellent results are obtained, even when starting from rather impure sulfonyl chlorides. Illustrative examples are given in Table I. 

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). 

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,... 

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. 

Other methods for the synthesis of l,4-dihydro-l,2,4,5-tetrazines 9 which can be explained by intermediate formation of nitrile imines 8 are the photolysis of 1,2,3-triazoles 2181 and sydnones 3,182 reaction of tetrazoles 4180 with tosyl chloride, elimination of pyridine from the pyridinium compounds 5,189-190 of hydrogen chloride from the hydrazonic acid chlorides 1 s.3-i88 or elimination 0f sulfinate from the a-sulfonyl hydrazone 7.189... 

Thiophenesulfinic acid 541,542 2-Thiophenesulfonyl chloride is dissolved in several parts of water and cooled whilst being treated gradually with zinc dust. When the odor of the sulfonyl chloride has disappeared the pasty mixture is filtered and the solid is washed free from zinc chloride by water. The residue consisting of zinc thiophenesulfinite and the excess of zinc dust is treated with sodium carbonate solution which converts the zinc salt into the sodium salt which is readily soluble in water. The solution is filtered, greatly concentrated on a water-bath, and acidified. The sulfinic acid is taken up in ether. On removal of the ether it is obtained as an oil that solidifies to needles, m.p. 67°, when kept in a vacuum over sulfuric acid. 

General directions for reduction of sulfonyl chlorides to sulfinic acids 543 A mixture of the sulfonyl chloride (20 g), sodium sulfite nonahydrate (50 g), and crushed ice (100 g) is shaken until the chloride has dissolved (about 3 h) the mixture is tested for alkalinity from time to time and dilute sodium hydroxide solution is added as necessary to prevent evolution of sulfur dioxide, whilst cooling by ice is maintained. Finally the mixture is filtered and the sulfinic acid is precipitated from the filtrate by gradual addition of concentrated hydrochloric acid. Yields average 80-90 %. 

PS-TsCl has also been used as a reagent for a-chlorination of ketones (eq 15). p-toluenesulfonyl chloride has been used for the same transformation however, the solid-supported toluene-sulfonyl chloride offers the advantage of rendering the lithium sulfinate by-product insoluble and thus easily removed from the reaction mixture. 

Miscellaneous Transformations. Cyanotrimethylsilane effects the transformation of acyl chlorides to acyl cyanides, a-chloro ethers and a-chloro thioethers to a-cyano ethers and a-cyano thioethers (eq 19), t-butyl chlorides to nitriles (eqs 20 and 21), 1,3,5-trisubstituted hexahydro-l,3,5-triazines to amino-acetonitriles, the cyanation of allylic carbonates and acetates (eqs 22 and 23), and the formation of aryl thiocyanates from aryl sulfonyl chlorides and sulfinates. The reagent has been used effectively in peptide synthesis and in a range of other synthetic applications. " ... 

For a long time, the organic chemistry of sulfur dioxide was limited to the formation of sulfinate salts and the sulfones derived therefrom. As shown, the sulfones are highly valuable synthetic intermediates for the construction of carbon-carbon single and double bonds, and very often with high stereoselectivity. More recently, the H-ene and hetero-Diels-Alder reactions of sulfur dioxide have been realized under conditions that avoid polymerization of alkenes, dienes, and other unsaturated compounds. Thus, alk-2-ene-1-sulfonyl chlorides are obtained readily from alkenes... 

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. 

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