Oxidation of diphenyl sulphide

Gragerov and Levit studied the oxidation of diphenyl sulphide by peroxomonosulphate in ethanol-acetic acid solvent containing H2 0, and found that the products, diphenyl sulphoxide and diphenyl sulphone, were unlabelled. They concluded that the oxidation is heterolytic and does not involve free-radicals. 

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Olah and coworkers56 found that treatment of dialkyl, arylalkyl and diaryl sulphides with nitronium hexafluorophosphate (or tetrafluoroborate) 32 at —78° in methylene chloride resulted in the formation of sulphoxides in moderate to high yields (Table 3). In the oxidation of diphenyl sulphide which affords diphenyl sulphoxide in 95% yield, small amounts of the ring nitration products (o- and p-nitrophenyl phenyl sulphides) were formed. However, diphenyl sulphone and nitrophenyl phenyl sulphoxide were not detected among the reaction products. 

The latter compound on oxidation again yields the sulphonic acid. Again, sulphuryl chloride reacts with benzene in the presence of aluminium chloride to give diphenylsulphone, (C6H5)2S02, a compound which can also be obtained by oxidation of diphenyl sulphide, (C6H5)2S. On the assumption that the phenyl radicals remain attached to the sulphur atom throughout these transformations, it is obvious that the hydroxyl radicals in sulphuric acid must also be directly attached to sulphur. 

An early study of the oxidation of diphenyl sulphoxide to the sulphone37 compared the rate for this reaction with that of the oxidation of the corresponding sulphide to the sulphoxide. The former reaction was shown to proceed approximately 200 times slower... 

If a mixture of diphenyl sulphide and the corresponding sulphoxide are treated with osmium tetroxide in boiling ether for 48 hours the sulphide is unchanged whilst the sulphoxide is converted into the sulphone in 96% yield with concomitant production of osmium trioxide . It thus seems that this method would be useful synthetically for the preparation of sulphones from sulphoxides containing sulphide functionalities. Ruthenium tetroxide may be used in place of osmium(VIII) oxide . 

Peracetic acid oxidation of 2,5-diphenyl-l,4-dithiadiene-l-oxide produces 2,5-diphenyl-l,4-dithiadiene-l, 1-dioxide in 72% yield without reaction with the sulphide sulphur atom40 (equation 13). This is rather surprising given the earlier evidence concerning relative rates37. 

Although this mechanism could explain the inertness of di-t-butyl sulphide towards oxidation due to the absence of a-hydrogen atoms, it was later ruled out by Tezuka and coworkers They found that diphenyl sulphoxide was also formed when diphenyl sulphide was photolyzed in the presence of oxygen in methylene chloride or in benzene as a solvent. This implies that a-hydrogen is not necessary for the formation of the sulphoxide. It was proposed that a possible reactive intermediate arising from the excited complex 64 would be either a singlet oxygen, a pair of superoxide anion radical and the cation radical of sulphide 68 or zwitterionic and/or biradical species such as 69 or 70 (equation 35). 

Diederich et al. had postulated that the highly reactive iron-oxo species, arising from oxygen transfer from the oxidant to the Fem site [87], should be greatly stabilised by enclosure within a dendritic superstructure. The catalytic potential of the dendrimers 6 a-c was determined in the epoxidation of alkenes [83 a, 88] (1-octene and cyclooctene) and the oxidation of sulphides [83 a] ((methylsulphanyl)benzene and diphenyl sulphide) to sulphoxides - in dichloro-methane with iodosylbenzene as oxidising agent. Compared to the known metal-porphyrin catalysts, 6a-c exhibit only low TON (7 and 28, respectively, for... 

Photo-oxidation of olefins in pyridine solution in the presence of FeCIs has been found to take one of three courses, depending on the substitution pattern of the substrate olefin. These routes lead to formation of a-chloroketones, gem-dichloroketones, and a,-dichloroketones, and have all been illustrated by their use in actual syntheses. a-Chloroketones have also been produced by irradiation of pyridine solutions of vinylsUanes or vinyl sulphides under similar conditions. DCA-sensitized photo-oxidation of l,2-diphenyl-3,3,4,4-tetramethylcyclobutene in MeCN leads to the corresponding ozonide in a process which occurs by initial formation of an oxirane. Jasmine lactone (12 ... 

Diphenyl sulphoxide, thiodiglycol sulphoxide, and diethyl sulphoxide are oxidised to the corresponding sulphones. Howard and Levitt studied the kinetics of oxidation of these compounds at pH 8 in a phosphate buffer (aqueous solution) and found the rates to be first-order with respect to peroxodisulphate and independent of the substrate concentration over the limited range employed (0.01-0.02 M). The removal of oxygen had no effect on the rate. Diethyl sulphide is oxidised very rapidly initially, then at the same rate as diethyl sulphoxide. Howard and Levitt concluded that the sulphide is first oxidised to the sulphoxide which in turn is oxidised to the sulphone, but Wilmarth and Haim point out that this interpretation cannot be correct, and conclude that the reaction must be more complex. 

Diphenyl sulphide appears to be a good trapping agent for dioxetans, and may provide evidence in photo-oxidations for dioxetan intermediates when these are not isolable.134 Thus, oxidation of the imidazole (77) to (79) is thought to... 

NO used for thioether oxidation to sulphoxides is unique in that it can be employed as a reagent in stoichiometric amounts or as a catalyst for autoxidation. Oxygen alone cannot oxidise thioethers at ambient temperatures and atmospheric pressures, so NO must be the active agent in the catalytic oxidation. There is strong correlation between the oxidative conversion of thioethers to sulphoxides and the concentration of [R S, NO ] complexes. The enhanced reactivity of an alkyl thioether such as dibutyl sulphide relative to diphenyl sulphide directly parallels the difference in the steady-state concentrations of the corresponding nitrosonium donor-acceptor complexes [22] [Bu S, NO ], [Ph S, NO ]. The same trend in the structure/reactivity relationship is more clearly shown in the oxidative conversion of the homologous thioethers in... 

Diphenyl diselenide, (CeH5)2Se2, is formed as a by-product in the preparation of phenyl selenide when magnesium phenyl bromide in ether solution reacts with selenium.5 A 2 per cent, yield is obtained when benzene, aluminium and selenium bromides react in dilute carbon disulphide solution. The product melts at 62° C.6 The corresponding oxide is an oil, B.pt. 230° C. at 65 mm.,7 and the sulphide, (C6H5)2Se2S, M.pt. 55° C., is obtained from sulphur chloride and phenyl selenide in carbon disulphide solution.8... 

In the other methods worked out since the war, diphenyl cyanoarsine is prepared by treating diphenyl arsenious oxide with hydrocyanic acid, or by treating either diphenyl chloroarsine or diphenyl arsenious sulphide with the cyanide of a heavy metal. The reaction between hydrocyanic acid and diphenyl arsenious oxide may be carried out at the ordinary temperature or by treatment in a closed tube at 100° C. for 2 hours ... 

By Arbusov and Related Reactions.—Details have been presented of the formation of phosphine oxides from alkyl benzoates and diphenyl-phosphinous chloride (16), although this route is not likely to be of preparative significance [see Chapter 3, Section 1, p. 52]. The sulphides (17) have been prepared from alkyl chloroacetates. Further syntheses of benzoylphosphine oxides (18) have appeared, and their dipole moments... 

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