5.6- Dimethyl-2- -methylthiol

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, ... 

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... 

HCI gas was bubbled into a cooled solution of 5-methoxy-2-[(3,5-dimethyl-4-methoxy-2-pyridinyl)methylthiol]-lH-benzimidazole (50 g) in dichloromethane (250 ml) until no more precipitation was observed. The reaction mixture was warmed to 40°C and again cooled to 10°C. The solid was filtered under suction and washed with dichloromethane to yield the product (49 g) as a cream colored fine granular solid. Yield was 88.2% of theoretical. Melting point 144°-148°C. 

Omeprazole from 5-methoxy-2-[(3,5-dimethyl-4-methoxy-2-pyridinyl)methylthiol]-lH-benzimidazole... 

The ring-opening reaction on 4-methyl-2-thia-7-aza-tricyclo[5.3.0.01,4]decan-8-one 39 was carried out by treatment with dimethyl(methylthio)sulfonium tetrafluoroborate (DMTSF) <20010L1781, 2004JOG33>. Methylthiolation of the thietane sulfur produces a transient alkylthiosulfonium salt which easily dissociates to the iV-acyliminium ion 40. Once formed, 40 readily undergoes loss of a proton to give the product 40 (Equation 11). 

Having collected the available experimental data one tries to construct what looks like a reasonable model. Small ligands such as water or dioxygen can obviously be fully treated but many of the other ligands will have to be truncated [41]. For amino-acid side chains, there is usually an obvious choice. For example, histidine can be replaced by imidazole, methionine by dimethyl sulfide, tyrosine by phenol, cysteine by methylthiol and so on. 

In a few cases these compounds have been identified. Dimethyl sulfide (56) and methylthiol butyrate (57) (MTB) were identified in the vaginal secretion of female hamsters (288, 289). Methylthiol butyrate is readily converted to methyl disulfide (58) (DMS) by hydrolysis and even more readily by aminolysis followed by air oxidation of the re-... 

Methylthiolation of 2-bromoanisole, giving (111), is brought about with dimethyl sulphoxide and NaH at 60—65 °C. 4-Bromoanisole gives a mixture of the corresponding 3- and 4-methylthio-isomers. Mono-halogenonaphthalenes on treatment with dimethyl sulphoxide, Bu OK, and Bu OH at 140 °C give naphthols, t-butyl ethers, and l-methylthio-2-... 

Functional Group Methylthiolation. The main feature of methylbis(methylthio)sulfonium hexachloroantimonate (MesSs SbClg) is the easy transfer of a methylsulfenylium ion to a variety of functional groups more nucleophilic than the sulfur of dimethyl disulfide. The low nucleophilicity of the disulfide and of the hexachloroantimonate ion allows the isolation, or the characterization, of positively charged reaction products. 

Simple thiols and organic sulfides, such as methylthiol, ethanethiol, dimethyl sulfide and dimethyl disulfide, give 100% production of the protonated parent [41,42], with the reactions taking place at the collisional rate limit. 

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