Alkyl sulphides

The alkyl sulphides or thioethers, the sulphur analogues of the ethers, are conveniently obtained by boiling alkyl halides with anhydrous sodium sulphide in alcoholic solution, for example ... 

Alkyl sulphides are the sulphur analogues of ethers from which they differ considerably in chemistry. They are unpleasant-smelling oils, insoluble in water but soluble in organic solvents. They tend to be comparatively inert. Mustard gas, CICH2CH2—S—CH2CH2CI, an oily liquid boiling at 216°C with a mustard-like smell, is highly poisonous and a vesicant, and for this reason found use in chemical warfare. 

Sulphur compounds, e.g., thiopropionate esters and metal dithiolates (Table la, AO 16 and 17), decompose hydroperoxides catalytically, i.e., one antioxidant molecule destroys several hydroperoxides through the intermediacy of sulphur acids [19,20]. Scheme 6 shows a simplified scheme for the antioxidant mechanism of simple alkyl sulphides. 

Scheme 6 Antioxidant mechanism of simple alkyl sulphides.

Alkyl sulphide complexes can be synthesized from RuC13 and R2S in ethanol at reflux [114b,c] ... 

Thermochemical data from the compilation of Stull et at., 1969. Entropy values are based on a 1 M standard state. The asterisk denotes symmetry-corrected quantities. Symmetry numbers were chosen as follows 18 for the n-alkanes, cis-3-hexene, dibuthyl sulphide, diethyl ether, and diethyl amine 2n for the cycloalkanes and 2 for all of the remaining ring compounds 3 for the alkanols, alkanethiols and alkyl amines 9 for the methyl alkyl sulphides... 

Although there are other more cost effective and efficient procedures, the periodate oxidation of dialkyl sulphides to the sulphoxides has been shown to proceed in high yield [24, 25, 29] thiols are oxidized to disulphides (95-100%) [29]. The potency of the quaternary ammonium periodate for the oxidation of sulphides is improved by the addition of wieso-tetraphenylporphinatoironflll) chloride [TPPFe(III)Cl] [27]. In contrast with the oxidation conducted in the absence of TPPFe(III)Cl [24,25], aryl sulphides are oxidized more rapidly than alkyl sulphides. 

Gas chromatography has been applied to the determination of a wide range of organic compounds in trade effluents including the following types of compounds which are reviewed in Table 15.15 aromatic hydrocarbons, carboxylic acids aldehydes, non ionic surfactants (alkyl ethoxylated type) phenols monosaccharides chlorinated aliphatics and haloforms polychlorobiphenyls chlorlignosulphonates aliphatic and aromatic amines benzidine chloroanilines chloronitroanilines nitrocompounds nitrosamines dimethylformamide diethanolamine nitriloacetic acid pyridine pyridazinones substituted pyrrolidones alkyl hydantoins alkyl sulphides dialkyl suphides dithiocaibamate insecticides triazine herbicides and miscellaneous organic compounds. 

King, J.E. and Coley-Smith, J.R., 1969. Production of volatile alkyl sulphides by microbial degradation of synthetic alliin and alliin-like compounds in relation to germination of scherotia of Sclerotium cepivorum Berk. Ann. Appl. Biol., 64 303—314. 

Two sections of Table 5 refer to the formation of thiacycloalkanes by cycli-sation of two different series of open chain precursors, namely, methyl alkyl sulphides and alkanethiols. The two sets of log M-values are remarkably similar, showing that to a reasonable approximation the equilibrium EM s for the formation of a ring is a quantity characteristic of that ring. This is again a consequence of the fact that enthalpies of formation and entropies for the simple compounds involved in the reactions considered are to a good approximation the sum of independent contributions from part-structures of the molecules. Were such an additivity rule perfectly obeyed, the effective molarities for the two series given and the corresponding QAH°- and 0AS -values, would be exactly the same. 

Chloromethyl alkyl sulphides and methyl phosphorodichloridite react together in a process that is catalysed by FeCIa or by BF3 etherate, probably via a phospho-nium intermediate (32). ... 

Extension of these ideas to alkyl sulphides indicated that they also... 

Hydroxylation of electron-rich aromatic rings, A -oxidation of amines, S-oxidation of alkyl sulphides and the conversion of aldehyde and ketones to acids and esters (apparent Baeyer-Villiger reactions) are amongst reactions catalysed by this class of flavoenzymes. 

Palladium-catalysed allylation has again been the subject of numerous reports. Of note is the use of O-allyl S-alklyl dithiocarbonate substrates which results in the production of allyl alkyl sulphides (Scheme 20). 3 These substrates circumvent catalyst poisoning problems normally associated with catalytic allylation of sulphur nucleophiles by generating the nucleophile in situ at a concentration which is never higher than that of the -allyl intermediate. 

The reactions between PCI5 and alkenes or alkynes have already been discussed extensively in connection with the synthesis of a variety of phosphonic acid types (as their acid dichlorides). Successful applications have also used alkenyl alkyl sulphides (to give the dichlorides 381) to an enyne (to give the dichloride 382) and to RSC CCl (to give 383)584,585 variation of the Pummerer reaction consists in the interaction of PCI5 and a dialkyl sulphoxide, during which a trichlorophosphonium salt intermediate is decomposed with SO2 to yield a (2-alkylthioethenyl)phosphonic dichloride (Scheme 34). ... 

---