Benzyl phenyl sulphide

Rajanikanth and Ravindranath44 have recently published a deoxygenation reaction for sulphoxides that uses metallic lithium in refluxing dimethoxyethane. Dialkyl and alkyl phenyl sulphoxides were reduced cleanly in yields around 70%, even if sterically hindered, but benzyl sulphoxides gave mixtures of products. For example, benzyl phenyl sulphoxide gave frans-stilbene (33%), benzyl phenyl sulphide (20%) and diphenyl disulphide (47%). These products can be rationalized by reaction pathways such as in equation (17) ... 

Benzyl phenyl sulphide, norbornene, cw-cyclooctene, and 4-vinyl-1-cyclohexene were obtained from Aldrich and (IS)-(-)-a-pinene from Fluka. Phenyl sulphide was prepared from benzene and sulphur chloride following the literature procedure[9]. Reference samples of sulphoxides and sulphones were prepared by oxidation of sulphides with sodium periodate[10] and hydrogen peroxide[ll] respectively. Reference samples of epoxides were made by following Kaneda et al.[ 2 procedure. Metal phthalocyanines[13] were prepared from appropriate metal salt, 1,2-dicyanobenzene with ammonium molybdate as catalyst and were characterized by elemental analysis. 

Benzyl phenyl sulphide was oxidized to benzyl phenyl sulphone quantitatively in 6h with iron phthalocyanine as catalyst. Experiments were similarly carried out with other metal phthalocyanines using phenyl and benzyl phenyl sulphides. Experiments using copper phthalocyanine, nickel phthalocyanine and no catalyst, were carried out for 24 h and the products analysed by HPLC. These results are presented in Table-1. In these experiments... 

Results in Table-1 show that with iron phthalocyanine (Fe(II)Pc), manganese phthalocyanine (Mn(II)Pc) and cobalt tetrasulphonatophthalocyanine (Co(II)TSPc) as catalyst both phenyl and benzyl phenyl sulphides could be quantitatively oxidized to corresponding sulphones in 3-6 h. However, oxidation of benzyl phenyl sulphide to the corresponding sulphone with vanadyl phthalocyanine took 18h. In case of copper phthalocyanine (Cu(II)Pc) and nickel phthalocyanine (Ni(II)Pc), no sulphone formation was detected even after 24h, and the products analysis by HPLC showed the formation of 61% and 4.2% benzyl phenyl sulphoxide, respectively. The results for the oxidation of benzyl phenyl sulphide with Ni(II)Pc as catalyst and without any catalyst (entry 9, 10 Table-1) show that Ni(II)Pc rather gave negative effect in these oxidations. 

Ethyl phenyl sulphide is lithiated mainly in the ortho position, but with significant amounts of meta and para lithiation and substitution products. Superbases, on the other hand, prefer to deprotonate afkylthio benzenes at benzylic or a-positions, rather than on the ring ... 

Chlorinolysis is another reaction mode observed in some sulphides, in which sulphur retains its oxidation state. For example, phenyl trityl sulphide and benzyl trityl sulphide were converted into trityl chloride and sulphenyl chlorides [26]. Thiirane and thietane reacted similarly with 3-(dichloroiodo)pyridine to afford chlorinated disulphides [25] ... 

Both of these compounds yield sulphides or thio-ethers. Thio-phenol by the diazo reaction yields di-phenyl sulphide, CeHs—S—Cell5, di-phenyl thio-ether and benzyl mercaptan yields di-benzyl sulphide, CeHs—CH2—S—CH2—CeHs, di-benzyl thio-ether. These sulphides on oxidation yield sulphones (p. 526). 

The selenium equivalent of the known rearrangement of benzyl phenyl sulphoxides to benzaldehydes and diphenyl sulphide is brought about under milder conditions, 110—130°C during 2—3 min., than those (210—280 °C) required for sulphoxides. ... 

Oxidation of phenyl hexyl sulphide with sodium metaperiodate gave also only a trace amount of the corresponding sulphoxide72. On the other hand, Hall and coworkers73 prepared benzylpenicillin and phenoxymethyl penicillin sulphoxides from the corresponding benzyl esters by oxidation with sodium metaperiodate in dioxane solution with a phosphate buffer. A general procedure for the synthesis of penicillin sulphoxides was reported later by Essery and coworkers74 which consists in the direct oxidation of penicillins or their salts with sodium metaperiodate in aqueous solution at pH 6.5-7.0. 1-Butadienyl phenyl sulphoxide 4475 and a-phosphoryl sulphoxides 4576 were also prepared by the same procedure. 

Experimental. The general conditions of experiments, and methods of investigations were similar to those described previously.However, extremely precise and reproducible results of crosslinking were achieved owing originally developed device for exposure (Pig in which the specimens may be rotated with chosen rate. Additionally, the selection of UV-sensitizers was ex-tented, and besides diphenyl sulphoxide, also dinaphtyl sulphoxide, methyl - benzyl sulphoxide, bis- p-chloro-phenyl sulphoxide, bis- 2,4-dichlorophenyl sulphoxide, were used. Also, some other compounds were examined, namely diphenyl sulphide and its p-nitro-p-amino- as well o,o-dicarboxy-derivatives, methiomethy-lene-diethyl phosphate and uranyl acetate. 

Ultraviolet Spectra.—Interaction between the chromophores in phenylsulphonyl-guanidines through an empty c/-orbital on S, and between the sulphone w-system and the guanidine chromophore, is indicated by u.v. spectra, while related studies show the lack of homoconjugation (through-space conjugation) in aryl benzyl sulphides. U.v. fluorescence and phosphorescence data indicate exciton interaction between the phenyl chromophores in diphenyl sulphide. ... 

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