Other Sulphur-containing Compounds

Other Sulphur-containing Compounds.—The stable complex [Pt(WS4)2] has been prepared as the tetraphenylphosphonium salt by the reaction of K2[Ptl6], (NH4)2WS4, and Ph4PCl. The [Pt(WS4)2] ion has D2h symmetry, with a planar 

Rudajevova and V. Pour, Coll. Czech. Chem. Comm., 1975, 40, 597. 

Blaise, A, Genly, and J. Bardolle, Bull. Soc. chim. France, 1974, 1229. 

Other Sulphur-containing Compounds.—The crystal structure of rubidium hydroxylamine-NN-disulphonate, Rb5 [0N(S03)2]2H, 3H20, has been determined by direct methods and refined.264 The structure contains two formula units in the space group Pi, and the two [0N(S03)2]2H 5 anions 

Elements of Group VI occupy each of two independent centres of symmetry. The two [0N(S03)2]3 groups (53) in each anion are joined by a symmetrical hydrogen bond, with 

The pseudohalide CF3S02NC0 has been synthesized267 by means of a new reaction involving trifluoromethanesulphonamide and chlorosulphonyl isocyanate  

Other Sulphur-containing Compounds.— The e.s.r. spectrum of NaS02 trapped in argon at 4 K has been measured. The compound is prepared by the codeposition of sodium atoms and SOg. From the observed data, NaS02 is non-planar, with the Na+ ion located 4.3oo from each of the oxygen atoms and 4.7flo from the sulphur atom. 

Lattice vibrational spectra of five polymorphic forms of thiourea have been 

The crystalline thiocarbonates BaCSg, TlgCSg, PbCS3 (two modifications), and CdCSa have been prepared and their i.r. spectra recorded. 

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Other compounds include the plant-derived sterols (phytosterols) and other sulphur-containing compounds found in onions and their relatives. Only a few of the more important examples will be discussed in the following sections. 

The ability to maintain and enhance tissue GSH may be of particular importance in controlling cytokines production in response to inflammatory stimuli, because the stimulatory influence of oxidant molecules and TNF-alpha, on NFkB activity, is decreased by GSH and other sulphur-containing compounds... 

Some of the other sulphur-containing compounds are less toxic and may be more potent. 

Thio-sugars and Other Sulphur-containing Compounds... 

Another approach was developed by Scott in the 1970 s (7.8) which utilises the same mechanochemistry used previously by Watson to initiate the Kharacsh-type addition of substituted alkyl mercaptans and disulphides to olefinic double bonds in unsaturated polymers. More recently, this approach was used to react a variety of additives (both antioxidants and modifiers) other than sulphur-containing compounds with saturated hydrocarbon polymers in the melt. In this method, mechanochemically formed alkyl radicals during the processing operation are utilised to produce polymer-bound functions which can either improve the additive performance and/or modify polymer properties (Al-Malaika, S., Quinn, N., and Scott, 6 Al-Malaika, S., Ibrahim, A., and Scott, 6., Aston University, Birmingham, unpublished work). This has provided a potential solution to the problem of loss of antioxidants by volatilisation or extraction since such antioxidants can only be removed by breaking chemical bonds. It can also provide substantial improvement to polymer properties, for example, in composites, under aggresive environments. 

The ortholithiation of benzenesulphinamides 119 is of use in the regioselective synthesis of mefa-substituted compounds 120 the sulphinamide group is used to set up two ortho relationships and then removed reductively (Scheme 52) . The same concept has been explored with other sulphur-containing orf/zo-directors °. 

Homocysteine (Hey) metabolism is closely linked to that of the essential amino acid methionine and thus plays a central role in several vital biological processes. Methionine itself is needed for protein synthesis and donates methyl groups for the synthesis of a broad range of vital methylated compounds. It is also a main source of sulphur and acts as the precursor for several other sulphur-containing amino acids such as cystathionine, cysteine and taurine. In addition, it donates the carbon skeleton for polyamine synthesis [1,2]. Hey is also important in the metabolism of folate and in the breakdown of choline. Hey levels are determined by its synthesis from methionine, which involves several enzymes, its remethylation to methionine and its breakdown by trans-sulphuration. 

Vulcanization by the traditional curing methods utilized in the rubber industry is based on sulfur or sulphur-containing compounds and is also the most widely applied technique for curing liquid rubbers containing macromolecules with double bonds. Chinons, peroxides, phenol formaldehyde resins, and other compounds are often used for curing liquid rubbers as an alternative sulfur vulcanization. 

Allium sativum and Allium ursinum preparations show a very similar qualitative composition of sulphur-containing compounds. Quantitative diiTerences are knovm for alliin/allicin and other cysteine sulphoxides and thiosulphinates, respectively. 

Reaction 4.1 is of particular importance it proceeds in accordance with the number of structural groups in the molecule of the hydrocarbon being investigated, and from the products of this reaction the structure of the hydrocarbon can be established [2]. The scope of application of this reaction is continually extending in recent years it has been shown to be applicable to other classes of organic compounds, particularly sulphur-containing compounds [3]. 

The preparation of sulphonamides by oxidation of organic sulphur-containing compounds has not been the method of choice for many workers. This is probably because of the ease with which other sulphonic acid derivatives may be converted into sulphonamides, in high yields. Notwithstanding this, there have been a few published oxidative methods and these will be discussed in this section. 

The role of sulphur-containing compounds in photopolymerization appears to have attracted some interest. Bis(j -methylpyridazinyl)-3,3 -disulphide has been found to initiate the photopolymerization of styrene but inhibits the thermal polymerization. The role of thiyl radicals (PhS-) in photoinitiated polymerization of vinyl monomers by aromatic thio-compounds has been postulated by several workers. In one study, flash photolysis was used to identify the nature of the radical. Sulphur-containing monomers such as 4-methyl-2-(vinylthio)thiazole and thiocyclanes have been photopolymerized and copolymerized with other vinyl monomers. Luca et al. have devised a mathematical model for the photopolymerization of 2,3-dimethylbutadiene and thiourea. 

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