Phenyl disulphide

Experiments—A few drops of thiophenol on a watch-glass are slowly evaporated to dryness on the water bath with a few cubic centimetres of very dilute ammonia solution (fume chamber). An oil remains which sets to a crystalline solid on cooling. It is phenyl-disulphide, melting point 61°. 

Phenyl-mercaptan.—Bunge investigated phenyl-mercaptan in the same manner as the corresponding alkyl compound. Phenyl-disulphide, (C,H,),S was formed at the positive pole. 

Thionyl chloride reacts with 2-phenyl-3-hydroxythietan to give 3-phenylallyl chloride rather than the expected 2-phenyl-3-chlorothietan. Of the 3-chloro-thiacycloalkanes, 3-chlorothietan is the most reactive in both 5, 1 Sff2 reactions. A substantial amount of ring-opening to allyl phenyl disulphide occurs in the reaction of 3-chlorothietan with thiophenoxide ion. Attack at sulphur by the sulphur nucleophiles has also been suggested in the reaction of 3-thietanones with hydrogen sulphide ion o mercapto-ketones and their di- and tri-sulphide derivatives are the only products, with no evidence of sulphur on the ct -position being found. 

Homolysis, Oxidation, and Reduction.—Photolysis converts 2-nitrosoimino-3-phenyl-2,3-dihydrobenzothiazole (48 R = Ph), with loss of nitric oxide, into bis[o-(N-phenylcyanamino)phenyl] disulphide in 74% yield. Under varied conditions, 2-imino-3-phenyl-2,3-dihydrobenzothiazole is also formed (20%). The relative rates of the photolysis of (48) were measured in a number of different solvents. An interpretation of the results in terms of a free-radical mechanism involving the biradical (49) was proposed."... 

In a 1 litre round-bottomed flask provided with an efficient double surface condenser, place 40 g. (39 ml.) of aniline, 50 g. (40 ml.) of carbon sulphide CAUTION inflammable) (1), and 50 g. (63-5 ml.) of absolute ethyl alcohol (2). Set up the apparatus in the fume cupboard or attach an absorption device to the top of the condenser (see Fig. 11, 8, 1) to absorb the hydrogen sulphide which is evolved. Heat upon an electrically-heated water bath or upon a steam bath for 8 hours or until the contents of the flask sohdify. When the reaction is complete, arrange the condenser for downward distillation (Fig. 11, 13, 3), and remove the excess of carbon disulphide and alcohol (CA UTION inflammable there must be no flame near the receiver). Shake the residue in the flask with excess of dilute hydrochloric acid (1 10) to remove any aniline present, filter at the pump, wash with water, and drain well. Dry in the steam oven. The yield of crude product, which is quite satisfactory for the preparation of phenyl iao-thiocyanute (Section IV.95), is 40-45 g. Recrystalhse the crude thiocarbanihde by dissolving it, under reflux, in boiling rectified spirit (filter through a hot water funnel if the solution is not clear), and add hot water until the solution just becomes cloudy and allow to cool. Pure sj/m.-diphenylthiourea separates in colourless needles, m.p, 154°,... 

Pheiiyl iso-thiocyanate may be prepared in quantity directly from aniline. Aniline, carbon disulphide and concentrated aqueous ammonia react to form the sparingly soluble ammonium phenyldithiocarbamate this is decomposed by lead nitrate to produce phenyl iso-thiocyanate ... 

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) ... 

In the reaction of the phenylacetonitrile carbanion with thiocyanates, a major side reaction leads to the formation of the dialkyl disulphides, as a result of the base-catalysed decomposition of the thiocyanate. This side reaction is reported to be insignificant in the reactions of the other carbanions. Phenylacetonitrile reacts with 1,2-ethanyl bisthiocyanate to produce 2-cyano-2-phenyl-1,3-thiolanes [52] under conditions analogous to those used for the synthesis of the thioethers (Scheme 4.12). 

S-phenyl thiobenzoate typical procedure in the presence of diphenyl disulphide. Photolysis of the telluroester (Ar = 4-FCgH4) in the presence of 6 equiv of diphenyl disulphide according to the standard for the formation of selenoesters gave 71% of the thiobenzoate after chromatography on silica gel (eluent hexane/ ethyl acetate, 9 1). The product had a melting point and spectral characteristics in accordance with those described in the literature. 

Thiotelluration of 1-styrylcyclopropane In a Pyrex glass tube were placed 1-styrylcy-clopropane (0.2 mmol, 28.8 mg, 0.4 M), diphenyl disulphide (0.2 mmol, 43.7 mg, 0.4 M), diphenyl ditelluride (0.2 mmol, 81.9 mg, 0.4 M) and CDCI3 (0.5 mL). The tube was filled with Ar, and the mixture was irradiated at 40°C for 7 h through a filter (hv >400 nm) with a tungsten lamp (500 W). The solvent was evaporated in vacuo. Purification by a recycling preparative HPLC (CDCI3) yielded 77 mg (84%, E/Z= 14 86) of 2-phenyl-l-(phenylthio)-5-(phenyltelluro)-2-pentene as a pale yellow oil. 

Some substituted guanidines have been obtained [457] by reaction of amines with the disulphide H2N(HN )C S S C( NH)NH2. Papers on the structure and p/fa s [458], and the synthesis [458, 459] of acylguanidines have been published. Reaction of guanidine with alkyl-, alkenyl-, and benzyl-halides, followed by distillation under basic conditions, is reported to give useful yields of amines [460]. A novel electrophilic substitution of benzene to give A -methyl-A -phenyl-guanidine amongst other products has been published [461 ]. 

Towards light, carbon disulphide possesses high refractive and dispersive powers, and in these properties is exceeded only by methylene iodide, bromonaphthalene and phenyl mustard oil. On this account it is used for filling hollow glass prisms for the production of spectra.4... 

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... 

Figure 4 shows the result of one such measurement on the phenyl dithiolene. The two lines on the plot are for carbon disulphide and the dithiolene. The relative slopes... 

Phenyl isothiocyanate may be prepared in quantity (Expt 6.98, Method 2) by allowing aniline to react with carbon disulphide to form phenyldithiocarbamic acid (cf. 1), which is isolated as the ammonium salt. Treatment of the latter with lead nitrate removes the elements of hydrogen sulphide to produce phenyl isothiocyanate. As indicated in the preparation of p-bromophenyl isothiocyanate which is given as a further example, a slightly modified procedure which requires the use of rectified spirit as a reaction solvent is necessary in order to obtain good yields of isothiocyanates from substituted anilines. 

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