Disulphides and Related Compounds

In addition to specific disulphides and related compounds discussed later in this Section, the preparation of meso- and d,l-bis(a-phenylethyl) disulphide and the synthesis and n.m.r. spectrum of aryl hydropolysulphides ArSxH (x = 2— 7) are of particular interest. 

Chlorocarbonylsulphenyl chloride ClCOSCl and related compounds have uses in synthesis, of thiazol-2-ones, and of alkyl chlorides from the corresponding thiols. The latter procedure involves a disulphide RSSCOCl, treatment with PhB giving the alkyl chloride, though some elimination accompanies the substitution reaction, and is the major reaction for cyclohexanethiol. Whereas aminolysis of ClCOSCl occurs at carbonyl carbon, that of FCOSCl involves displacement of Cl from S. ... 

Chromatographic Analysis.—Chromatographic adsorption-analysis, the most delicate method of separation of closely related compounds, depends on the simultaneous adsorption and separation of mixtures of organic compounds, such as natural dyes, biochemical products, isomerides, hydrocarbons, etc., in suitable solvents such as petroleum, ether, chloroform, carbon disulphide and water. 

In Scheuer (1973), investigations concerning sulphur-containing compounds in lipids of brown algae are reviewed which are biogenetically related to the dictyopterenes (Moore et al., 1972). The spectroscopically identified compounds belong to the classes of alkyl thioacetates, open-chain disulphides, and l,2-dithiepin-5-ones as well as organic tri- and tetra-sulphides. 

Baumann next found that cystine, on reduction with zinc and hydrochloric acid, was converted into a new base, which he called cysteine this gave the same products on decomposition as cystine, into which it was easily reconverted by oxidation. He therefore recognised that these compounds were related to each other, as a mercaptan is to a disulphide consequently the formula... 

Rolek et al tried to distinguish between viscosity, temperature and composition in their influence on the effects of molybdenum disulphide dispersions in oils. They used a series of white oils, mineral oils, and the same mineral oils with some polar additives removed. The results were not entirely clear, but they supported Tsuya s findings (see below) on the effect of viscosity. However, they also seemed to indicate a more specific effect of temperature and the presence of polar additives. It seemed that there was a specific inhibiting effect of polar additives in suppressing any friction reduction by the molybdenum disulphide. In addition they identified a temperature effect distinct from its effect on viscosity, and suggested that this might be related to a transition temperature, possibly associated with desorption of polar compounds. 

The specific heat of mixtures of liquids can rarely be calculated additively from the specific heats of the components. There is generally a considerable deviation from the law of mixtures, and the calculated value is always larger than one would expect. Mixtures of hquids which are closely related chemically, such as ethyl and methyl alcohol, chloroform and carbon disulphide, behave normally mixtures of water with alcohol, or of alcohol with other organic hquids, show large deviations. It is noteworthy that heat is evolved on mixing these hquids, an indication that chemical combination also is taking place. This is probably the reason for the alteration in the heat capacity, since the specific heat of liquid chemical compounds cannot be calculated additively from the specific heats of the components. The regularities shown by sohd bodies do not hold even approximately for hquids. 

Additions of hydrazoic acid to carbon-sulphur double bonds may conceivably be of the general type outlined in equation (88) but do not constitute a synthetic route to azides. Recent corrections to the earlier literature relating to this field are, however, noteworthy. It was originally suggested that thiocarbamoyl azides " (193) were obtained from organic isothiocyanates and hydrazoic acid. The spectroscopic studies of Lieber and co-workers " have now established that the products are in fact thiatriazoles (194). The reactions of sodium azide with isothiocyanates , and carbon disulphide , which were also previously considered to furnish organic azides, have now been shown to produce the heterocyclic compounds 195 and 196 respectively. 

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