Halides sulfonic acid chloride

Sulfonic acid chlorides from halides via isothiouronium salts s. 18, 562 Hal SO2GI... 

Sulfonic acid chlorides from halides Hal SOgCl... 

This reaction, parallel with 10-77, is the standard method for the preparation of sulfonyl halides. Also used are PCI3 and SOCI2, and sulfonic acid salts can also serve as substrates. Sulfonyl bromides and iodides have been prepared from sulfonyl hydrazides (ArS02NHNH2, themselves prepared by 10-126) by treatment with bromine or iodine.Sulfonyl fluorides are generally prepared from the chlorides, by halogen exchange. 

Aromatic sulfonyl chlorides can be prepared directly, by treatment of aromatic rings with chlorosulfuric acid. ° Since sulfonic acids can also be prepared by the same reagent (11-7), it is likely that they are intermediates, being converted to the halides by excess chlorosulfuric acid. The reaction has also been effected with bromo-and fluorosulfuric acids. 

Diaryl sulfones can be formed by treatment of aromatic compounds with aryl sulfonyl chlorides and a Friedel-Crafts catalyst. This reaction is analogous to Friedel-Crafts acylation with carboxylic acid halides (11-14). In a better procedure, the aromatic compound is treated with an aryl sulfonic acid and P2O5 in polypho-sphoric acid. Still another method uses an arylsulfonic trifluoromethanesulfonic anhydride (ArS020S02CF3) (generated in situ from ArS02Br and CF3S03Ag) without a catalyst. ... 

A commonly used and important reaction of sulfonic acids, or sulfonates, is their conversion to sulfonyl chlorides by treatment with phosphorus halides, or sometimes with thionyl chloride. Although it is easy to postulate mechanisms for this conversion, the exact path followed has never been determined. Similarly, although mechanisms can be suggested for other known reactions involving sulfonic acids, such as the cleavage of dialkyl ethers by anhydrous sulfonic acids (Klamann and Weyerstahl, 1965), or the formation of sulfones by treatment of an aromatic hydrocarbon with a mixture of sulfonic acid plus polyphosphoric acid (Graybill, 1967), nothing truly definitive is known about the details of the actual mechanisms of these reactions. 

General Reaction Chemistry of Sulfonic Acids. Sulfonic acids may be used to produce sulfonic acid esters, which are derived from epoxides, olefins, alkynes, allenes, and ketenes, as shown in Figure 1 (10). Sulfonic acids may be converted to sulfonamides via reaction with an amine in the presence of phosphorus oxychloride [10025-87-3], POCl3 (11). Because sulfonic acids are generally not converted direcdy to sulfonamides, the reaction most likely involves a sulfonyl chloride intermediate. Phosphorus pentachloride [10026-13-8] and phosphorus pentabromide [7789-69-7] can be used to convert sulfonic acids to the corresponding sulfonyl halides (12,13). The conversion may also be accomplished by continuous electrolysis of thiols or disulfides in the presence of aqueous HQ [7647-01-0] (14) or by direct sulfonation with chlorosulfuric acid. Sulfonyl fluorides are typically prepared by direct sulfonation with fluorosulfuric acid [7789-21-1], or by reaction of the sulfonic acid or sulfonate with fluorosulfuric acid. Halogenation of sulfonic acids, which avoids production of a sulfonyl halide, can be achieved under oxidative halogenation conditions (15). 

Fluorinated and Chlorfluorinated Sulfonic Acids. The synthesis of chlorinated and fluorinated sulfonic acids has been extensively reviewed (91,92). The literature discusses the reaction of dialkyl sulfides and disulfides, sulfoxides and sulfones, alkanesulfonyl halides, alkanesulfonic acids and alkanethiols with oxygen, hydrogen chloride, hydrogen fluoride, and oxygen—chloride—hydrogen fluoride mixtures over metal halide catalysts, such as... 

Alkyl sulfates, tosylates, and other esters of sulfuric and sulfonic acids can be converted to alkyl halides with any of the four halide ions.979 Neopentyl tosylate reacts with Cl, Br, or I without rearrangement in HMPA.980 Similarly, allylic tosylates can be converted to chlorides without allylic rearrangement by reaction with LiCl in the same solvent.981 Inorganic esters are intermediates in the conversion of alcohols to alkyl halides with SOCl2, PC15, PC13, etc. (0-67), but are seldom isolated. 

Strong Brpnsted acids are also available to induce acylations.3,8,9 Perfluoroalkane-sulfonic acids were shown to be highly effective. Certain metal powders, such as Zn, Cu, Al, and Fe, were also found to effect acylations with acyl chlorides. The de facto catalysts are the in situ formed corresponding metal halides.3,8 A number of other catalysts were developed over the years however, many of these are effective only for the acylation of highly reactive aromatics, such as heterocycles.9... 

The at complex from DIB AH and butyllithium is a selective reducing agent.16 It is used tor the 1,2-reduction of acyclic and cyclic enones. Esters and lactones are reduced at room temperature to alcohols, and at -78 C to alcohols and aldehydes. Acid chlorides are rapidly reduced with excess reagent at -78 C to alcohols, but a mixture of alcohols, aldehydes, and acid chlorides results from use of an equimolar amount of reagent at -78 C. Acid anhydrides are reduced at -78 C to alcohols and carboxylic acids. Carboxylic acids and both primary and secondary amides are inert at room temperature, whereas tertiary amides (as in the present case) are reduced between 0 C and room temperature to aldehydes. The at complex rapidly reduces primary alkyl, benzylic, and allylic bromides, while tertiary alkyl and aryl halides are inert. Epoxides are reduced exclusively to the more highly substituted alcohols. Disulfides lead to thiols, but both sulfoxides and sulfones are inert. Moreover, this at complex from DIBAH and butyllithium is able to reduce ketones selectively in the presence of esters. 

Sulfonic acids are converted to the corresponding acid halides in much the same way as carboxylic acids. Thionyl chloride is the best reagent for the preparation of methanesulfonyl chloride (83%). By heating with a large excess of thionyl chloride, however, p-toluenesulfonic acid is converted into its anhydride (87%). Benzenesulfonyl chloride is made in 80% yield by the action of either phosphorus pentachloride or phosphorus oxychloride at 180° on sodium benzenesulfonate. Chlorosulfonic and fluorosulfonic acids are used in the conversion of sodium p-chloro-benzenesulfonate to the corresponding sulfonyl halides (85 8S>%). ... 

Esters of aliphatic and aromatic sulfonic acids are conveniently prepared in high yields from alcohols and sulfonyl halides. A basic medium is required. By substituting sodium butoxide for sodium hydroxide in butanol, the yield of n-butyl p-toluenesulfonate is increased from 54% to 98%. Ethyl benzenesulfonate and nuclear-substituted derivatives carrying bromo, methoxyl, and nirro groups are prepared from the corresponding sulfonyl chlorides by treatment with sodium ethoxide in absolute ethanol the yields are 74-81%. Pyridine is by far the most popular basic medium for this reaction. Alcohols (C -Cjj) react at 0-10° in 80-90% yields, and various phenols can be converted to aryl sulfonates in this base. "... 

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