Dimethylsulfone

Chloroquinoline (401) reacts well with potassium fluoride in dimethylsulfone while its monocyclic analog 2-chloropyridine does not. Greater reactivity of derivatives of the bicyclic azine is evident also from the kinetic data (Table X, p. 336). 2-Chloroquinoline is alkoxylated by brief heating with methanolic methoxide or ethano-lic potassium hydroxide and is converted in very high yield into the thioether by trituration with thiocresol (20°, few hrs). It also reacts with active methylene carbanions (45-100% yield). The less reactive 3-halogen can be replaced under vigorous conditions (160°, aqueous ammonia-copper sulfate), as used for 3-bromoquino-line or its iV-oxide. 4-Chloroquinoline (406) is substituted by alcoholic hydrazine hydrate (80°, < 8 hr, 20% yield) and by methanolic methoxide (140°, < 3 hr, > 90% yield). This apparent reversal of the relative reactivity does not appear to be reliable in the face of the kinetic data (Tables X and XI, pp. 336 and 338) and the other qualitative comparisons presented here. 

British investigators (Haddow and Timmis 1951) synthesized and studied esters of the methanesulfonic acid. The most active derivative was the dimethylsulfonic ester of 1,4-butanedione, known as busulfan. Busulfan interacts with the thiol groups of proteins and amino acids some of its metabolites can alkylate the thiols of cysteine, peptides and proteins. Busulfan exerts selective cytotoxic activity in hematopoietic bone marrow cells and inhibits the formation of granulocytes and platelets. It slightly affects the lymphoid tissue. 

Styrene glycol dimesylate [ 1,2-Ethanediol, 1-phenyl-, dimethylsulfonate], 55,... 

Several approaches have been tried in order to facilitate the conversion process and lower the conversion temperatures, e. g. by using appropriate sulfonium groups (tetrahydrothiophene derivatives) and/or different counter ions. With chloride as a counter ion [80], the synthesis of 2,5-dimethoxy-PPV can be performed at room temperature starting from the corresponding dimethylsulfon-ium polyelectrolyte precursor. 

Borodina E, Kelly DP, Schumann P, et al. 2002. Enzymes of dimethylsulfone metabolism and the phylogenetic characterization of the facultative methylotrophs Arthrobacter sulfonivorans sp. nov., Arthrobacter methylotrophus sp. nov., and Hyphomicrobium sulfonivorans sp. nov. Arch Microbiol 177 173-83. 

The octet rule is one of the cornerstones of chemical bonding theory. While the vast majority of molecules conform, apparent exceptions occur for molecules incorporating second-row (and heavier) main-group elements. Apparent refers to the fact that molecules such as dimethylsulfoxide and dimethylsulfone may either be represented in terms of structures with ten and twelve valence electrons, respectively, surrounding sulfur, or as zwitterions with the normal complement of eight valence electrons (see also discussions in Chapters 5 and 16). 

The results (electrostatic-fit charges based on Hartree-Fock 6-3IG wavefunctions) are ambiguous. Relative to dimethylsulfide as a normal-valent standard , the sulfur in oxygen loses about half an electron, and the sulfur in dimethylsulfone loses 1.7 electrons. This would seem to suggest that dimethylsulfoxide is halfway to being a zwitterion, but that dimethylsulfone is most of the way. Charges on sulfur in sulfur tetrafluoride and sulfur hexafluoride (relative to sulfur difluoride) show more modest effects, in particular for the latter. Overall, it appears that hypervalent molecules possess significant ionic character. 

Fig. 1 Voltammetric reduction ofThCU (2.6 X 10 M) in molten dimethylsulfone at 400 K (Pt cathode, scan rate = 0.1 V s , 0.25 M LiCi) (reprinted from Journai of Aiioys and Compounds, Vol. 228, L. Martinot,...

U(III) species and a second three-electron reduction to give U(0) metal. The first reduction, U(IV)/U(III) couple, is elec-trochemically and chemically irreversible except in hexamethylphosphoramide at 298 K where the authors report full chemical reversibility on the voltammetric timescale. The second reduction process is electrochemically irreversible in all solvents and only in dimethylsulfone at 400 K was an anodic return wave associated with uranium metal stripping noted. Electrodeposition of uranium metal as small dendrites from CS2UCI6 starting material was achieved from molten dimethylsulfone at 400 K with 0.1 M LiCl as supporting electrolyte at a platinum cathode. The deposits of uranium and the absence of U CI3, UCI4, UO2, and UO3 were determined by X-ray diffraction. Faradaic yield was low at 17.8%, but the yield can be increased (55.7%) through use of a mercury pool cathode. 

Beryllium and certain beryllium compounds A,A- w-(2-Chloroethyl)-2-naphthylamine (chlornaphazine) Bis(chloromethyl) ether and chloromethyl methyl ether 1,4-Butanediol dimethylsulfonate (Myleran )... 

Barnes, et al. (22) have studied reaction (3) in the presence of O2 using a competitive rate technique which utilizes H2O2 as the OH photolytic precursor. This avoids the use of NOx containing precursors which nave been shown to produce unreliable results in studies of OH reactions with organo-sulfiir compounds (24.251. They find up to 30% yields of dimethylsulfone, (013)2802, and suggest that reaction (4b) is important If reaction (4b) is an elementary reaction and OH is regenerated, then our study of reaction (3) would have obtained values of k s which were too low and, hence, underestimated the importance of the addition channel. One apparent inconsistency between the recent work of Barnes, et al. (231 and our study (2) is that Barnes, et al. observed only DMSO2 as a product of reaction (4) neither DMSO nor MSA was observed. Since we would not have observed an O rate enhancement if the adduct + O2 reaction proceeded entirely via channel (4b), our results imply that an addition channel other than (4b) must be important The only addition pathways which seem reasonable are (4a), (4b), and... 

Sodium nitrite Aluminum oxide Acetamide Bromine Dimethylsulfone Sodium methylate... 

Selective inversion recovery experiments i.e. only select frequencies within the powder pattern are excited, have also been performed on 2H for the purposes of studying molecular motion. Initial experiments were performed on deuterated dimethylsulfone (DMS) to demonstrate the utility of the experiment.46 Selective inversion recovery curves were fitted to a suitable motional model, a two-site jump model in the case of DMS, to yield the motional rates as a function of temperature. A significant feature of this work is that the activation energy for the motion so obtained differs markedly from that obtained from earlier 13C chemical shift anisotropy lineshape studies. 

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