Alkane disulfides

The azeotrope formation between sulfur compounds, thiols, alkane disulfides, and thiophenes, and petroleum hydrocarbons have been extensively studied by the Anglo-Iranian Oil Co. the results have been published in several papers (87, 88). Research workers of this company have also secured data on vapor-temperature relationships of sulfur compounds (110). 

The relative order of increasing adsorptivity of the various sulfur compounds and associated hydrocarbon to be adsorbed on sihca gel, given by Haresnape, Fidler, and Lowry (151), is aromatic hydrocarbons, thiophenes, alkanethiols, alkane disulfides, aromatic and cycloalkanethiols, alkane sulfides, and cyclic sulfides. (The more polar sulfur compounds such as sulfoxides, sulfones, and sulfonic acids would be expected to be more readily adsorbed and therefore would fall at the end of the list.)... 

Sulfur reacts with alkanes to either dehydrate (eq. 1), oxidize, forming carbon disulfide and hydrogen sulfide (eq. 2), or cyclize, forming thiophenes (eq. 3). The products of alkane sulfurization depend on the temperature, the time at the temperature, and the stmcture of the hydrocarbon (1). 

Chlorine Ammonia, acetylene, alcohols, alkanes, benzene, butadiene, carbon disulfide, dibutyl phthalate, ethers, fluorine, glycerol, hydrocarbons, hydrogen, sodium carbide, finely divided metals, metal acetylides and carbides, nitrogen compounds, nonmetals, nonmetal hydrides, phosphorus compounds, polychlorobi-phenyl, silicones, steel, sulfides, synthetic rubber, turpentine... 

Successive multiple insertions of an aryl isocyanide (ArNC) into the S-S bond of a diaryl disulfide (ArS)2 occurs in the presence of Pd(PPh3)4 to produce the corresponding poly(imino)alkane endcapped with an arylthio group (Equation (65)).167 Products of higher molecular weights are formed when isolated poly(imino)alkanes are again subjected to the conditions of the insertion reaction (up to n — 9). 

The preparation and application of SAM systems patterned by STM and their use in catalysis was demonstrated by Wittstock and Schuhmann [123]. The patterning (local desorption) of SAMs from alkane thiols on gold was performed by scanning electrochemical microscopy (SECM), followed by the assembly of an amino-deriva-tized disulfide and coupling of glucose oxidase to form a catalytically active pattern of the enzyme. The enzymatic activity could be monitored/imaged by SECM. 

Thiols, sulfldes, and disulfides are dissolved in a sufficiently pure solvent (in general, ethanol for nonpolar compounds and water for polar tw-substituted alkane thiols) and then applied onto the cleaned gold surface. 

In polar and H-bonding solvents such as acetone, tetrahydrofuran or methanol CgQ is essentially insoluble. It is sparingly soluble in alkanes, with the solubility increasing with the number of atoms. In aromatic solvents and in carbon disulfide, in general appreciable solubilities are observed. A significant increase of the solubility takes place on going from benzenes to naphthalenes. Although there are trends for the solution behavior of Cjq, there is no direct dependence of the solubility on a certain solvent parameter like the index of refraction n. When the solubility is... 

The most important flavour compound in raw onions is thiopropanal-S-ox-ide, the lachrymatory factor [145,146]. Other important flavour compounds are 3,4-dimethyl-2,5-dioxo-2,5-dihydrothiophene and alkyl alkane thiosulfonates such as propyl methanethiosulfonate and propyl propanethiosulfonate with a distinct odour of freshly cut onions [35, 36, 147]. Various thiosulfinates that have a sharp and pungent odour may also contribute to the flavour of onions. These compounds, however, are rapidly decomposed to a mixture of alkyl and alkenyl monosulfides, disulfides and trisulfides (Scheme 7.3) of which dipropyl disulfide, methyl ( )-propenyl disulfide, propyl ( )-propenyl disulfide, dipropyl trisulfide and methyl propyl trisulfide are the most important contributors to the aroma of raw and cooked onions (Table 7.5, Fig. 7.6) [148-150]. Recently, 3-mercapto-2-methylpentan-l-ol was identified in raw and cooked onions eliciting intense meat broth, sweaty, onion and leek-like odours [142, 151]. 

Alkanes do not usually react with xenon difluoride at room temperature, while thermally initiated fluorinations of organic molecules have received much less attention than liquid-phase reactions. Zajc and Zupan16 have shown that several hydrocarbons react with xenon difluoride when heated to 95-120 °C. Reproducible results can be observed only when a teflon jacket is used in the stainless reactor with appropriate preconditioning. Cyclohexane is converted to fluorocyclohexane, while the reaction with -hexane gives three monofluoro-substituted products. Fluorination of adamantane results in the formation of four products, from whose distribution it is evident that the difference in the reactivity between the secondary and the tertiary carbon atom is much larger than the difference between the reactivities of the primary and secondary carbon atoms of hexane. Liquid-phase functionalization of a tertiary carbon atom is observed in reactions in carbon disulfide, where 1-fluoroadamantane is formed17. 

With these early successes in hand, a key question arising is that of whether RNA-targeted DCC yields compounds that can serve as relevant leads for further medicinal chemistry studies Our group is currently engaged in efforts to demonstrate that the answer to this question is in the affirmative. For example, building on the efforts with the HIV-1 FSS RNA detailed above, non-reducible analogs incorporating a hydrocarbon (olefin or saturated alkane) bioisostere for the disulfide... 

Reaction of a four-carbon unit with sulfur sources such as hydrogen sulfide, carbon disulfide, and elemental sulfur is one of the traditional thiophene syntheses that belong to this category (Equation 18). A wide variety of hydrocarbons, for example, alkanes, alkenes, dienes, alkynes, and diynes, serve as four-carbon units. Another practical method is the sulfuration of 1,4-dicarbonyl compounds (Paal synthesis). The method has become very popular with development of sulfuration reagents such as Lawesson s reagent. The reaction of a,/3-unsaturated nitriles with elemental sulfur in basic media, Gewald synthesis, is also useful for the preparation of 2-aminothiophenes which are important compounds in dyestuff and pharmaceutical industries. 

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