Sulfoxides from aromatic compounds

The ORD and CD curves of chiral sulfinamides derived from aromatic sulfinic acids show a strong Cotton effect centered at 240 to 256 nm (83). The position of this Cotton effect, its dependence on the solvent used, and the amplitude reveal a complete analogy with that observed in alkyl aryl sulfoxides and aromatic menthyl sulfin-ates. Thus, the positive sign of the Cotton effect observed in the ORD curves of dextrorotatory sulfinamides is indicative of the (5)-configuration around sulfur in these compounds. 

On the pages which follow, general methods are illustrated for the synthesis of a wide variety of classes of organic compounds including acyl isocyanates (from amides and oxalyl chloride p. 16), epoxides (from reductive coupling of aromatic aldehydes by hexamethylphosphorous triamide p. 31), a-fluoro acids (from 1-alkenes p. 37), 0-lactams (from olefins and chlorosulfonyl isocyanate p. 51), 1 y3,5-triketones (from dianions of 1,3-diketones and esters p. 57), sulfinate esters (from disulfides, alcohols, and lead tetraacetate p. 62), carboxylic acids (from carbonylation of alcohols or olefins via carbonium-ion intermediates p. 72), sulfoxides (from sulfides and sodium periodate p. 78), carbazoles... 

Synthesis of aromatic sulfoxides is usually effected preparatively by one of the two following methods. First, aromatic compounds can be treated with thionyl chloride under Friedel-Crafts conditions di-p-tolyl sulfoxide has thus been obtained from toluene,232 diphenyl sulfoxide from benzene,233,234 and bis-Q -hydroxyphenyl) sulfoxide from phenol.235... 

Alkane sulfonates are mainly produced by two methods, i.e. the process of sulfochlorination and the process of sulfoxidation. In both processes, a radical chain reaction takes place and therefore the alkane starting material must be free from branched compounds, olefines and aromatics because such compounds will act as chain-stoppers in the chain reactions. Highly pure straight alkanes of paraffin fractions from 13 to 18 carbon atoms are used, with an optimum in the range of 14-17 carbons in the chain. 

The removal of AAT sulfur compounds from the diesel fuel feedstock by extractive desulfurization (EDS), either adsorption or solvent extraction, is a viable alternative to HDS." This approach is based on the polarity difference between the AAT family of compounds and the hydrocarbons found in the diesel fraction. Because AATs comprise several dozen different compounds, they represent a range of solvent polarities, in some cases quite similar to the aromatic compounds found in diesel fuel. The critical polarity difference between individual hydrocarbon and thiophenic compounds is therefore variable, and in some cases may be insufficient to allow a functional separation by extraction. Polarity difference can, however, be increased by oxidizing the thiophenic sulfur to the corresponding more polar mono- and dioxides, the alkylated-aryl-thiophene-sulfoxide or sulfone (AATS). This in turn facilitates the separation, and several EDS processes therefore are designed to oxidize the AAT before extraction of the sulfur." ... 

Extraction Solvent. Dimethyl sulfoxide is immiscible with alkanes but is a good solvent for most unsaturated and polar compounds. Thus, it can be used to separate olefins from paraffins (93). It is used in the Institute Fransais du Pntrole (IFF) process for extracting aromatic hydrocarbons from refinery streams (94). It is also used in the analytical procedure for determining polynuclear hydrocarbons in food additives (qv) of petroleum origin (95). 

Notable examples of general synthetic procedures in Volume 47 include the synthesis of aromatic aldehydes (from dichloro-methyl methyl ether), aliphatic aldehydes (from alkyl halides and trimethylamine oxide and by oxidation of alcohols using dimethyl sulfoxide, dicyclohexylcarbodiimide, and pyridinum trifluoro-acetate the latter method is particularly useful since the conditions are so mild), carbethoxycycloalkanones (from sodium hydride, diethyl carbonate, and the cycloalkanone), m-dialkylbenzenes (from the />-isomer by isomerization with hydrogen fluoride and boron trifluoride), and the deamination of amines (by conversion to the nitrosoamide and thermolysis to the ester). Other general methods are represented by the synthesis of 1 J-difluoroolefins (from sodium chlorodifluoroacetate, triphenyl phosphine, and an aldehyde or ketone), the nitration of aromatic rings (with ni-tronium tetrafluoroborate), the reductive methylation of aromatic nitro compounds (with formaldehyde and hydrogen), the synthesis of dialkyl ketones (from carboxylic acids and iron powder), and the preparation of 1-substituted cyclopropanols (from the condensation of a 1,3-dichloro-2-propanol derivative and ethyl-... 

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