Sulfonated arene

Sulfonation (Section 12 4) Sulfonic acids are formed when aromatic compounds are treated with sources of sulfur trioxide These sources can be concentrated sulfuric acid (for very reactive arenes) or solutions of sulfur trioxide in sulfuric acid (for ben zene and arenes less reactive than ben zene)... 

Of these the most important are the sulfonic acids In general however sulfonic acids are not prepared by oxidation of thiols Arenesulfomc acids (ArS03H) for example are prepared by sulfonation of arenes (Section 12 4)... 

Sulfonic acids are prone to reduction with iodine [7553-56-2] in the presence of triphenylphosphine [603-35-0] to produce the corresponding iodides. This type of reduction is also facile with alkyl sulfonates (16). Aromatic sulfonic acids may also be reduced electrochemicaHy to give the parent arene. However, sulfonic acids, when reduced with iodine and phosphoms [7723-14-0] produce thiols (qv). Amination of sulfonates has also been reported, in which the carbon—sulfur bond is cleaved (17). Ortho-Hthiation of sulfonic acid lithium salts has proven to be a useful technique for organic syntheses, but has Httie commercial importance. Optically active sulfonates have been used in asymmetric syntheses to selectively O-alkylate alcohols and phenols, typically on a laboratory scale. Aromatic sulfonates are cleaved, ie, desulfonated, by uv radiation to give the parent aromatic compound and a coupling product of the aromatic compound, as shown, where Ar represents an aryl group (18). 

Tnfluoroacetic anhydnde in a mixture with sulfuric acid is an efficient reagent for the sulfonylation of aromatic compounds [44] The reaction of benzene with this system in nitromethane at room temperature gives diphenyl sulfone in 61% yield Alkyl and alkoxy benzenes under similar conditions form the corresponding diaryl sulfones in almost quantitative yield, whereas yields of sulfones from deactivated arenes such as chlorobenzene are substantially lower [44] The same reagent (tnfluoroacetic anhydride-sulfunc acid) reacts with adamantane and its derivatives with formation of isomeric adamantanols, adamantanones, and cyclic sultones [45]... 

Yosida et al. [41] found that p-t< rr-butylcalix[6]ar-ene can extract Cu from the alkaline-ammonia solution to the organic solvent. Nagasaki and Shinkai [42] described the synthesis of carboxyl, derivatives of calix-[n]arenes ( = 4 and 6) and their selective extraction capacity of transition metal cations from aqueous phase to the organic phase. Gutsche and Nam [43] have synthesized various substituted calix[n]arenes and examined the complexes of the p-bromo benzene sulfonate of p-(2-aminoethyl)calix[4]arene with Ni, Cu , Co-, and Fe. ... 

E The writing has again been revised at the sentence level, streamlining the presentation, improving explanations, and updating a thousand small details. Several little-used reactions have been deleted (the alkali fusion of arene-sulfonic acids to give phenols, for instance), and a few new ones have been added (the Sharpless enantioselective epoxidation of alkene.s, for instance). 

D. Arene Sulfonate-Arylsulfone (Sulfone-Fries) Rearrangement.171... 

D. Arene Sulfonate-Aryl Sulfone (Sulfone-Fries) Rearrangement71... 

Nucleophilic substitutions of halogen by the addition-elimination pathway in electron-deficient six-membered hetarenes by sulfinate anions under formation of sulfones have been described earlier120. The corresponding electron-poor arenes behave similarly121 (equation 30). A special type of this reaction represents the inverse Smiles rearrangement in equation 31122. 

Beside these free radical reactions of sulfur dioxide, its electrophilic reactions generating sulfinates with organometallic compounds453,454 or sulfinic acids with arenes under Friedel-Crafts conditions455 are well known. To complete these three-component syntheses, the sulfinates prepared first are transformed to sulfones by reactions with appropriate electrophiles, discussed earlier in this chapter, i.e. equation 82. 

It has been known472 that sulfones are side-products in the course of sulfonation of arenes with sulfur trioxide or its derivatives. Generally, this reaction may be expressed by equation 90. Mechanistic investigations have indicated473 that this reaction follows the pathway shown in equation 91. 

Although anaerobic desulfonation of arene sulfonates, in which the sulfonate is used as a source of sulfur, has been described in a Clostridium sp., the product was not identified (Denger et al. 1996,... 

The specific structure of [(H20)5Ni(py)]2+ was observed in the complexes with the second-sphere coordination of calix[4]arene sulfonate.715 There are two different [(H20)5Ni(py)]2+ cations in the complex assembly. In one the hydrophobic pyridine ring is buried in the hydrophobic cavity of the calixarene with the depth of penetration into the calixarene cavity being 4.3 A (Figure 9). The second independent [(H20)5Ni(py)]2+ cation is intercalated into the calixarene bilayer. 

Figure 9 Complex assembly of [(H20)5Ni(py)]2+ and calix[4]arene sulfonate.715...

Hydrotopy is the phenomenon by which otherwise water-insoluble compounds can be solubilized in the aqueous solution of some compounds, e. g. arene sulfonates. These compounds, known as hydrotopes, are readily water-soluble. The aqueous concentrated solutions (20 to 50%) of the hydrotopes can significantly increase the water solubility of many water-insoluble compounds. 

M. Vazquez, J. Bobacka, M. Luostarinen, K. Rissanen, A. Lewenstam, and A. Ivaska, Potentiometric sensors based on poly(3,4-ethylenedioxythiophene) (PEDOT) doped with sulfonated calix[4]arene and calix[4]resorcarenes. J. Solid State Electrochem. 9, 312-319 (2005). 

A variety of functional groups resist reduction arene rings, N02, COOMe, CONH2, sulfones, nitrile, and ArHal. Nitriles can bind to the metal, and the N lone pair is not effectively masked by acid addition so lower rates can be encountered if this group is present. Alkynes, alkenes, and imines are the best-studied substrates for which reduction is efficient. 

Butyl butyrate, 4 460 p- -Butylcafix[4]arene, 14 165 4- -Butylcalix[8]arene-p-sulfonic acid, 23 722 D-re-Butyl carbonate, physical properties, 6 306t... 

The relative ease with which aryl benzyl sulfoxides undergo homolytic dissociation (Rayner et al., 1966) as compared to aryl benzyl sulfides or sulfones is supportive of this idea that ArSO radicals are easier to form than ArS or ArS02 radicals. Another interesting set of observations is the following. Booms and Cram (1972) found that optically active arene-sulfinamides ArS(0)NRPh (R = H or CH3) racemize thermally very readily at room temperature and that this racemization is the result of a free radical chain reaction (160) that is initiated by the dissociation of some of the sulfinamide into an ArSO and a PhNR radical (159). While the length of the inhibition... 

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