Dimethyl thioether

In the presence of H + this gives the acidic form (CH3)2SOH, a species which is formed also by the reaction of OH" with dimethyl thioether. 

Dimethylquinoxaline, AR40 6,T D imethy I qu i noxa 1 ine, AR41 Dimethyl sulfide, ABOO Dimethyl thioether, ABOO... 

S— R—S—R Thioether (sulfide) CH3—S—CH3 Dimethyl thioether Dimethyl sulfide... 

SR C—S—C 2-Thiapropane Dimethyl sulfide Dimethyl thioether... 

Atkinson R, Perry RA, Pitts JN Jr. 1978. Rate constants for the reaction of hydroxyl radicals with carbonyl sulfide, carbon disulfide and dimethyl thioether over the temperature range 299-430 K. Chem Phys Lett 54 14-18. 

Q.ll) (Q.ll) methane, thiobis-, dimethylsulfane, dimethyl sulfide, (methylsulfanyljmethane, 2-thiapropane, dimethyl thioether (75-18-3) FEMA 2746... 

Dimethyl sulphide (Dimethyl thioether, methyl sidphide)... 

Dimethyl sulfide [75-18-3]., thioethers, thioformaldehyde [865-36-17, and thiophene [110-02-1] are among other possible carbon disulfide hydrogenation... 

A variety of cleavage conditions have been reported for the release of amines from a solid support. Triazene linker 52 prepared from Merrifield resin in three steps was used for the solid-phase synthesis of aliphatic amines (Scheme 22) [61]. The triazenes were stable to basic conditions and the amino products were released in high yields upon treatment with mild acids. Alternatively, base labile linker 53 synthesized from a-bromo-p-toluic acid in two steps was used to anchor amino functions (Scheme 23) [62]. Cleavage was accomplished by oxidation of the thioether to the sulfone with m-chloroperbenzoic acid followed by 13-elimination with a 10% solution of NH4OH in 2,2,2-trifluoroethanol. A linker based on l-(4,4 -dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde) primary amine protecting group was developed for attaching amino functions (Scheme 24) [65]. Linker 54 was stable to both acidic and basic conditions and the final products were cleaved from the resin by treatment with hydrazine or transamination with ra-propylamine. 

The readily available benzotriazolyl derivative of dimethyl sulfide, compound 821, can be alkylated on a-carbon in a stepwise manner to provide (a,a-disubstituted)alkyl thioethers 823 (Scheme 131). Hydrolysis of these thioethers under mild conditions (5% H2S04 at room temperature) furnishes ketones 824 in high yields. The anion derived from mono substituted (benzotriazol-l-yl)methyl thioether 822 adds to butyl acrylate to give intermediate 826 that can be hydrolyzed to y-ketoester 825. In another example of reactivity of a-(benzotriazol-l-yl)alkyl thioethers, treatment of thioether 822 with BunLi followed by phenyl isocyanate converts it into a-ketoanilide 828, via intermediate adduct 827 <1998JOC2110>. 

Introduction of trimethylsilyl substituents attached directly to the ot-carbon atom of a-(benzotriazol-l-yl)alkyl thioethers provide new opportunities. Thus, treatment of lithiated monosubstituted a-(benzotriazol-l-yl)alkyl thioethers with chlorotrimethylsilane produces a-(trimethylsilyl)alkyl thioethers 837. In reactions with hexamethyl-disilathiane and cobalt dichloride, thioethers 837 are converted to thioacylsilanes 838 that can be trapped in a Diels-Alder reaction with 2,3-dimethylbutadiene to form 2-alkyl-4,5-dimethyl-2-trimethylsilyl-3,6-dihydro-27/-thiopyrans 839 (Scheme 133) <2000JOC9206>. 

An unusual carbene-thioether hybrid ligand 174 was synthesized and applied in the rhodium-catalyzed asymmetric hydrogenation of dimethyl itaconate by Chung and co-workers however, the selectivity and activity were low (Table 27.7, entry 34) [135]. 

Still another related method consists in reacting dienes with dimethyl disulphide in the presence of iodine, to produce the corresponding bis(o ,/J-dmiethylmercapto) derivative241-243. Again, characteristic fragmentation is obtained in the standard El spectra. However, this method involves complications if the double bonds are separated by less than four methylene groups due to the formation of cyclic thioethers. 

In contrast with the reactions involving sulphide or hydrogen sulphide anions, aryl alkyl thioethers and unsymmetrical dialkyl thioethers (Table 4.3) are obtained conveniently by the analogous nucleophilic substitution reactions between haloalkanes and aryl or alkylthiols under mildly basic conditions in the presence of a quaternary ammonium salt [9-15] or polymer-supported quaternary ammonium salt [16]. Dimethyl carbonate is a very effective agent in the formation of methyl thioethers (4.1.4.B) [17]. 

Example The oxidative addition of dimethyl disulfide (DMDS) transforms the double bond to its 1,2-bis-thiomethyl derivative (a). Induced by charge localization at either sulfur atom, the molecular ions of DMDS adducts are prone to a-cleavage at the former double bond position (b). This gives rise to sulfonium ions that are readily identified from the mass spectrum (Chap. 6.2.5). The method can be extended to dienes, trienes, and alkynes. [70,71] (For the mass spectral fragmentation of thioethers cf. Chap. 6.12.4). 

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