Dimethylsulfoxide reduction

Jonkers H. M., Van der Maarel M., Van Gemerden H., and Hansen T. A. (1996) Dimethylsulfoxide reduction by marine sulfate-reducing bacteria. FEMS Microbiol. Lett. 136, 283-287. 

A new acid catalyst of potential use in the Bischler-Napieralski cyclization is P2O5 in methanesulfonic acid. The phenethylamines used in isoquinoline syntheses are usually prepared from the reduction of the corresponding /S-nitrostyrenes. A more versatile procedure starts with a substituted benzyl chloride which is converted to the nitrile using sodium cyanide in DMSO (dimethylsulfoxide). Reduction of the nitrile with LiAlH4 in the presence of AICI3 gives the desired amine in excellent yield. Benzylamines or their quaternary salts may also be utilized in appropriate solvents in place of benzylic chlorides, so that they too may act as nitrile precursors. ... 

Cyano-de-diazoniations of the Sandmeyer type have been used for the synthesis of aromatic nitriles for many decades (example Clarke and Reed, 1964), as cyanide ions are comparable to bromide and iodide in many respects. A homolytic cyano-de-diazo-niation that does not use metal ions as reductant or ligand transfer reagent was described by Petrillo et al. (1987). They showed that substituted diazosulfides (XC6H4 — N2 — SC6H5), either isolated or generated in situ from arenediazonium tetrafluoroborates and sodium benzenethiolate, react with tetrabutylammonium cyanide in dimethylsulfoxide under photon stimulation, leading to nitriles (XC6H4CN). The method worked well with eleven benzenediazonium ions substituted in the 3- or 4-position, and was also used for the synthesis of phthalo-, isophthalo-, and tere-... 

Ito et al.40 examined the electrochemical reduction of C02 in dimethylsulfoxide (DMSO) with tetraalkylammonium salts at Pb, In, Zn, and Sn under high C02 pressures. At a Pb electrode, the main product was oxalic acid with additional products such as tartaric, malonic, glycolic, propionic, and n-butyric acids, while at In, Zn, and Sn electrodes, the yields of these products were very low (Table 3), and carbon monoxide was verified to be the main product even at a Pt electrode, CO was mainly produced in nonaqueous solvents such as acetonitrile and DMF.41 Also, the products in propylene carbonate42 were oxalic acid at Pb, CO at Sn and In, and substantial amounts of oxalic acid, glyoxylic acid, and CO at Zn, indicating again that the reduction products of C02 depend on the electrode materials used. 

Tetraazamacrocyclic complexes131 of cobalt and nickel were found110 to be effective in facilitating the reduction of C02 at -1.3 to -1.6 V versus SCE (Table 8). An acetonitrile-water mixture and water were used as solvents, while in dry dimethylsulfoxide no catalytic reduction of C02 took place. Using an Hg electrode, both CO and H2 were produced, where total current efficiencies were greater than 90%. The turnover numbers of the catalysts were 2-9 h 1. The catalytic activity lasted for more than 24 h and the turnover numbers of the catalysts exceeded 100. A protic source was required to produce both CO and H2, and the authors suggested that both products may arise from a common intermediate, which is most likely a metal hydride. The applied potential for C02 reduction was further reduced by using illuminated p- Si in the presence of the above catalysts.111... 

In the case of the DMSO reductase family, as pointed out above, the metal centre is bound to two molecules of the cofactor. DMSO reductase itself catalyses the reduction of dimethylsulfoxide to dimethylsulfide with incorporation of the oxygen atom of DMSO into water. The active site of the oxidized enzyme is an L2MoVI0(0-Ser) centre, which, upon reduction, loses the M=0 ligand to give a L2MoIV(0-Ser) centre. In the catalytic... 

This reaction sequence illustrates how the rates of many base-catalyzed reactions can be enhanced greatly by substitution of dimethylsulfoxide for the usual hydroxylic solvents. Other examples of the enhanced reactivity of anions in dimethylsulfoxide are found in Wolff-Kishner reductions and Cope elimination reactions. The present reaction illustrates the generation of an aryne intermediate from bromobenzene. ... 

Propyleine (104) also is derivable from ketone 437. Reduction of 437 with LAH gave the equatorial alcohol (438) which was converted into the corresponding mesylate (439). Clean elimination was effected by heating 439 with potassium carbonate in dimethylsulfoxide to yield a 3 1 mixture of propyleine (104) and isopropyleine (440) (Scheme 54) 455). 

Divalent metal ions, reversible binding, 38 153 Dixenon cation, 46 68 Dizinc enzymes, 40 351-354 DMA, see Dicarbomethoxy acetylene DMAD complexes, see Dicarboxymethoxy dithiolene complexes DMAE, see Dimethylarsinoylethanol DMF, reduction potentials, 33 57 DMSO, see Dimethylsulfoxide DNA... 

The arylpropionic acid derivatives are useful for the treatment of rheumatoid arthritis and osteoarthritis, for reduction of mild to moderate pain and fever, and for pain associated with dysmenorrhea. Side effects of the drugs are similar to but less severe than those described for the salicylates. Those who are sensitive to salicylates also may be sensitive to and have adverse reactions when taking ibuprofen and related drugs. Acute hypersensitivity to ibuprofen has been reported in patients with lupus. The hypersensitivity reaction to sulindac can be fatal. The use of sulindac has also been linked to cases of acute pancreatitis. The use of dimethylsulfoxide (DMSO) topically in combination with sulindac has been reported to induce severe neuropathies. The concurrent use of ibuprofen with aspirin reduces the antiinflammatory effects of both drugs. Ibuprofen is contraindicated in patients with aspirin sensitivity leading to bronchiolar constriction and in patients with an-gioedema. As with all NSAIDs, renal and liver function should be normal for adequate clearance of the drugs. 

CH3CN, dimethylsulfoxide, dimethylfor-mamide (DMF) and pyridine, of course, is reversible at the timescale of cyclic voltammetry the first unambiguous studies appeared in 1965, the radical being identified by electron spin resonance (ES R) [34, 35]. The reversibility has been demonstrated by cyclic voltammetry in pyridine even in a basic medium, the second reduction step occurring at a much more negative potential is irreversible [36]. In the presence of proton donors, and, of course, in protic solvents, it is known that O is unstable and that the reduction of O2 proceeds via a two-electron step [10, 27, 37]. The superoxide ion is moderately basic... 

The most simple and straightforward approach for ED of metal sulfide thin films is the co-reduction of elemental sulfur and metal cations in an organic medium such as dimethylsulfoxide (DMSO).37 39) Because elemental sulfur is dissolved as polymeric species such as S8,39) the overall reaction for ED of CdS thin film can be written as... 

Eggins and McNeill compared the solvents of water, dimethylsulfoxide (DMSO), acetonitrile, propylene carbonate, and DMF electrolytes for C02 reduction at glassy carbon, Hg, Pt, Au, and Pb electrodes [78], The main products were CO and oxalate in the organic solvents, while metal electrodes (such as Pt) which absorb C02 showed a higher production for CO. In DMF, containing 0.1 M tetrabutyl ammonium perchlorate and 0.02 M C02 at a Hg electrode, Isse et al. produced oxalate and CO with faradaic efficiencies of 84% and 1.7%, respectively [79], Similarly, Ito et al. examined a survey of metals for C02 reduction in nonaqueous solution, and found that Hg, Tl, and Pb yielded primarily oxalate, while Cu, Zn, In, Sn, and Au gave CO [80, 81]. Kaiser and Heitz examined Hg and steel (Cr/Ni/Mo, 18 10 2%) electrodes to produce oxalate with 61% faradaic efficiency at 6 mA cm-2 [82]. For this, they examined the reduction of C02 at electrodes where C02 and reduction products do not readily adsorb. The production of oxalate was therefore explained by a high concentration of C02 radical anions, COi, close to the surface. Dimerization resulted in oxalate production rather than CO formation. 

The one-electron reduction of 3,4,5-trimethoxyphenyl glyoxal with potassium tert-butoxide in dimethylsulfoxide gives rise mainly to the cis-semidione, while upon electrolysis in dimethylformamide, in the presence of tetraethyl ammonium perchlorate as the carrier electrolyte, the main product is the trans isomer (Sundaresan Wallwork 1972), Scheme 3-41. 

Shein (1983) paid attention to the following facts. Dimethylsulfoxide used as a solvent may contain water and MeSNa. Water may hydrolyze the initial 4-nitro-l-chlorobenzene (spectrophotometry uses solutions extremely diluted with respect to the substrate). The presence of MeSNa may cause the formation of 4-nitrophenylmethyl sulfide and its anion radical, and this was not included in the kinetic equations. Solodovnikov (1976) considers neither the production of 4-nitroanisole nor the formation of the other products of a deeper reduction of the substrate. 

Bromonaphthalene does not react with benzenethiol (thiophenol) salts. However, if electric current is passed through a solution containing 1-bromonaphthalene, the tetra-butylammonium salt of thiophenol, and dimethylsulfoxide, then l-(phenylthio)naphthalene is produced in 60% yield. When the reaction is conducted in acetonitrile, it leads to naphthalene above all (Pinson Saveant 1978 Saveant 1980 Amatore et al. 1982). In the electrochemically provoked reaction, it is sufficient to set up the potential difference corresponding to the initial current of the reduction wave to transform 1-bromonaphtahalene into 1-naphthyl radical. The difference in the consumption of electricity is rather remarkable In the absence of thiophenolate, bromonaphthalene is reduced, accepting two electrons per single molecule in the presence of thiophenolate, 1-bromonaphthalene is re-... 

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