Methylthiolation

With I2 as cataly.st the main product is perchloro-methylthiol (CI3CSCI). Reaction products with E2 depend on the conditions used, typical products being SE4, SFs, -SjFio, F2C(SF3)2, F 2C(SF5)2, F3CSF5 and F3SCF2SF5. 

Compounds 4 and 5 have reactions in the six-membered ring similar to those of pyridine. As examples, compound 199 is aminated (92MI3), and compound 218 reacts with a number of primary and secondary amines to give compounds such as 219 (97UKZ64). Triazolopyridinone 220 can be converted into the hydrazine 221 either via the chloro compound or via the thione and methylthiol (85LA1922). 

The reaction mechanism of the DNA (cytosine-5)-methyltransferase-catalyzed cytosine methylation was investigated at the MP2 and DFT levels [98JA12895]. This system has been modeled by 1-methylcytosine 117, methylthiolate, and trimethylsulfonium. The cytosine methylation is initiated by an attack of the anionic methylthiolate at Cg of the cytosine ring (Scheme 77). The formation of the methylthiolate adduct 118 of the neutral 117 was found to be endothermic in the gas phase and in solution. However, the MP2 and DFT results differ... 

Ethyl methyl ketone, 10, 23 17, 74 Ethyl methyl ketoxime, 11, 59 Ethyl methylmalonate, 17, 56 Ethyl i-methylthiol-3-phthaIimidopro-pane-3,3-dicatboxylate, 14, 58 Ethyl nitrite, 10, 22, 25... 

Methyl 2-thienyl ketone, 18,1 i-Methylthiol-3-phthalamidopropane-3,3-dicarboxylic acid, 14, 59 6-Methyluracil, 17, 63 Monochlorumethyl ether, 14, 92 Morland salt, 15, 75 Myristic acid, 18, 84 Myristyl alcohol, 10, 64 Myristyl bromide, 16, 26 16, 37... 

Another example is the introduction of sulfur functionalities into the keto esters at the a- or a positions, which can be eliminated after the reduction. Methylthiol... 

The negatively charged S atom possesses three lone pairs of electrons that can potentially be shared with other atoms. Thus methylthiolate anion is a nucleophile. 

Hitherto, thio ether formation has clearly been proved only in the case of the ji-donor substituted 4-nitrosophenetol and the electron-rich l-methyl-2-nitrosoimidazole. The low yields of this adduct (about 2% at 1 1- and about 10% at 1 5-stoichiometry for 4-nitrosophenetol reacting with GSH56) may be the reason for its rare discovery. However, other nitrosoarenes should yield this family, too. Semiempirical molecular orbital calculations (MNDO) indicate a similar positive charge at the exposition of the N-(methylthiol-S -yl)-aniline cation and -4-anisole cation as well (Scheme 6). Furthermore, formation of l-(glutathion-S -yl)-2-naphthylamine was reported to occur in mixtures of 2-nitrosonaphthalene and GSH12. 

Markovnikov orientation. However, the product is too labile for storage at room temperature and must be reacted further at low temperature (examples are substitutions with methylthiol that work also with 137 and 138 [33]). Upon warming to room temperature the product JV-(l-bromoethyl)pyrrolidinone releases HBr and forms the linear dimer ( )-l,l -(3-methyl-l-propene-l,3-diyl)-bis(2-pyrrolidinone) that is most easily obtained by this technique [58]. 

Since ab initio calculations are non-trivial for alkanethiols with long chains, methylthiols and other short-chain thiols on Au(lll) have recently received considerable attention. While longer chains with their flexibility and non-negligible chain-chain interactions are essentially a defining feature of SAMs, methylthiols at least supposedly exhibit the same headgroup-substrate interaction. However, due to the different balance of the interactions (chain-chain versus headgroup-substrate), it is not possible to extrapolate the results from short-chain thiols to longer-chain thiols. 

The sulfones 367 (R = H and Me) obtained from 3-(indol-3-yl)propionate esters with the anion of dimethyl sulfoxide were cyclized, losing methylthiol, via 368 in the presence of p-toluenesulfonic acid in hot acetonitrile, ... 

Figure 1.5. Plan view of Cu(lll)/CH3S- pseudo-(lOO) reconstruction assuming a commensurate [ 4 ] registry of the overlayer and substrate. The methylthiolate species are represented by the S head-group atoms alone, shown as the darkest spheres. The Cu atoms of the reconstructed pseudo-(lOO) layer are shown more darkly shaded than those of the underlying substrate. For clarity the reconstructed overlayer has been omitted from the lower right-hand side of the diagram, exposing the outermost unreconstructed Cu(l 11) layer.

The action of methylthiol in ammoniacal methanol yields 5-methyl-thio derivatives91 the symmetrical bis(3-methylthio-l,2,4-thiadiazol-5-yl)sulfide (165) is thus accessible from the appropriate 5-mercapto and 5-chloroheterocycles91 (see also ref. 168). 

N-Acetylphenylglycine was obtained directly in a 91% yield when a solution of (3) in methanol/water (9 1) was refluxed for 3 h in the presence of potassium carbonate (2 eq). A desulfurization by the methylthiolate anion produced by the hydrolysis of (3) accounts for this result [295]. In that way VV-acetyl phenylglycine was obtained in a 60% yield, by a three-step procedure, from benzonitrile. 

Sulfenyl Chloride Bis-[trifluoro-methylthiol-fluoro-metlianc ElOa 250 (CS - CF-SCI)... 

Lower members of the series of salts formed between organic sulfoxides and perchloric acid are unstable and explosive when dry. That from dibenzyl sulfoxide explodes at 125°C [1], Dimethyl sulfoxide explodes on contact with 70% perchloric acid solution [2] one drop of acid added to 10 ml of sulfoxide at 20° C caused a violent explosion [3], and dibutyl sulfoxide behaves similarly [4]. A fatal explosion resulted from mistakenly connecting a DMSO reservoir to an autopipette previously used with perchloric acid [5], (The editor has met a procedure for methylthiolation of aromatics where DMSO was added to excess 70% perchloric acid he did not feel justified in trying to scale it up.) Explosions reported seem usually to result from addition to excess sulfoxide. Aryl sulfoxides condense uneventfully with phenols in 70% perchloric acid, but application of these conditions to the alkyl sulfoxide (without addition of the essential phosphoryl chloride) led to a violent explosion [4]. Subsequent investigation showed that mixtures of phenol and perchloric acid are thermally unstable (ester formation ) and may decompose violently, the temperature range depending on composition. DSC measurements showed that sulfoxides alone... 

---