Carbon disulphide generation

Carbon disulphide should not be used as the solvent for alkylation of fS-diketones, as the carbanion reacts preferentially with the solvent to generate the dithiocarboxyl-ate derivative, which undergoes mono- and dialkylation (Scheme 6.9) [95]. Ketene thioacetals have also been isolated from acetophenones (60-80%) and cyclopenta-diene (80%) using an ultrasound technique in carbon disulphide [96] and, in a similar manner, pyrazol-5-ones form pyrazole-4-dithiocarboxylic esters [97]. 

Reaction of S( D2) and S( Pi) atoms (generated by photolysis of COS in the gas phase) with acetylene yields carbon disulphide, benzene, and thiophene. With hexafluorobut-2-yne, however, only perfluorotetramethylthiophene is formed, although on prolonged irradiation, more complex products such as thiophenes (161) and (162) can be isolated. Highly reactive thiirenes and thio-formylmethylenes have been proposed as intermediates. 

Realgar is insoluble in water, but when it is boiled in water, it changes to As S3 generating hydrogen sulphide gas. When it is treated v/ith dilute bromine water, it becomes arsenious acid, and with iodine solution in carbon disulphide, Asl. V/hen it is boiled in nitric acid, it become arsenic acid and sulphuric acid. With dilute ammonia solution no change occurs, but with cone, ammonia solution the crystal surface is attacked. It is only slightly soluble in carbon disulphide or benzene. 

In addition to the desired species, the fullerene soot contains a multitude of insoluble components like soot particles or graphitic fragments. Moreover, there may be polycyclic aromatic hydrocarbons also. The separation from insoluble contaminants may be affected by extraction because the fuUerenes, and most of all the small ones, exhibit significant solubility in some organic solvents (refer to Section 2.4.1.1). Toluene is most commonly used for this process. Other possible solvents include chlorinated aromahc species, carbon disulphide, benzene and hexane. As an alternative, the fullerene part of the raw material may be separated by sublimation. In any case a mixture of the generated fuUerenes is obtained which has to be resolved into its constituents. In most cases chromatography is used to this purpose. 

The carbanion (187), generated by treatment of the isothiochro-man with butyllithium, reacts with alkyl or silyl halides, carbon disulphide or other reagents to give 1-substituted derivatives.197... 

Mesoionic thiazoles such as (69) can be considered to be potential precursors in basic media of cyclic azomethine ylids. These mesoionic thiazoles can be generated from 5-(tert-butylamino)thiazolium chlorides (68). They can undergo 1,3-dipolar cycloaddition reactions with carbon disulphide. The initial cycloadducts (70) and (71) rapidly eliminate tert-butyl isothiocyanate at room temperature to give the thiazolium-... 

In all cases the heat of combustion of the solvent to be destroyed needs to be known. In almost every case the water generated in the destruction will be discharged as water vapour and so the lower or net calorific value is the appropriate one to use and it is the one quoted here. The only common solvent which has no hydrogen to convert to water and therefore has identical higher and lower calorific value is carbon disulphide. 

Transient Species.—Pioneering studies by Johnson and co-workers have shown that monomeric thioformaldehyde is generated when methane reacts with small sulphur-containing molecules, such as carbon disulphide, carbonyl sulphide, or hydrogen sulphide, at low pressure in a radio-frequency discharge tube. On the basis of these results, Johns and Olson prepared thioformaldehyde, under slightly different conditions, from dimethyl disulphide in the presence of sulphur hexafluoride. The reaction path suggested was ... 

The syntheses of bis-l,3-dithiolylidene compounds noted above, involving treatment of 1,3-dithiolium salts with bases, are thought to proceed through carbene intermediates. These may be generated in other ways, for example, by the action of carbon disulphide on acetylenes (81 R = CF3) and by the action of triphenylphosphine on the l,3-dithiole-2-thione (83 R = CF3). In the first of these two methods, more complex products. 

The reaction is performed most advantageously by generating the required starting material (150) in situ thus a stirred mixture of iV-methyl-JV-benzoylphenylglycine, acetic anhydride, and carbon disulphide evolves carbon dioxide, affording (154) in 96% yield. The procedure is particularly useful when the oxazolium 5-olate is not isolable. ... 

The formation of compounds (54)—(56) from perfluorobut-2-yne and carbon disulphide at 100 °C has been interpreted in terms of the generation of the 1,3-dithiolium carbene (57), evidence for which has been obtained through trapping experiments,e.g.,... 

Desulphurization of l,2-bis(trifluoromethyl)vinylene trithiocarbonate (75), best obtained by reaction of 2,3-dichlorohexafluorobut-2-ene with potassium trithiocarbonate in dimethylformamlde, with triphenylphosphine in benzene yields the bidithiole (76) in 90% yield. The last compound is also a product of the thermal reaction between carbon disulphide and perfluorobut-2-yne, which leads to the generation of the 1,3-dithiolium caibene (77) (see p. 54). ... 

Alkoxybenzo-l,3-dithioles (32), conveniently prepared by generating benzyne in the presence of carbon disulphide and the appropriate alcohol, > react with thiols, active-methylene compounds, indoles and pyrroles, activated benzenes, and fluoroboric acid to give products of types (31), (33), (34), and (35) (Scheme 1). Thermal decomposition of 2-alkoxybenzodithioles leads to dibenzotetrathiafulvalene (36). Deprotonation of benzo-l,3-dithiolium salts, in the presence of methanol, acetone, and other reactants, produces compounds of types (32) and (34), as well as dimers of type (36). ... 

Carbene reactions are also involved when electron-deficient acetylenes are heated with carbon disulphide.Full details have now been published for these addition reactions, in which intermediates of type (70 R = CF, or C02Me) are postulated. Generation of benzyne, from 1-aminobenzotriazole and lead tetra-acetate, in the presence of carbon disulphide, also leads to a 1,3-dithiole carbene, and hence to a variety of complex products. ... 

Gilbert BC, Laue HAH, Norman ROC, Sealy RC (1975) Electron spin resonance studies, part 16. Oxidation of thiols and disulphides in aqueous solution formation of RS, RSO, RSO2, RSSR-, and carbon radicals. J Chem Soc Perkin Trans 2 892-900 Gilbert BC, Holmes RGG, Laue HAH, Norman ROC (1976) Electron spin resonance studies. Part L. Reactions of alkoxyl radicals generated from alkylhydroperoxides and titanium (III) ion in aqueous solution. J Chem Soc Perkin Trans 2 1047-1052... 

Thermolysis of diazotetrazole (718) gives rise to atomic carbon in the presence of propane, a mixture of but-l-ene, cis- and rrans-but-2-ene, isobutene, and methylcyclopropane, as well as propene, methane, and acetylene, is obtained/ Tris(methylimino)methane (720), the first nitrogen analogue of tri-methylenemethane, is generated by low-temperature photolysis of the tetrazoline l-Methoxy-5-phenyltetrazole (721) rearranges to the tetrazole 7V-oxide (722) at 200 The main product of the reaction of diazomethane with the tetrazolyl disulphide (723) is the rearranged thione (724)/ Irradiation of the... 

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