Das Lösungsmittel Dimethylsulfoxid

Metal-free, green and efficient oxidative α halogenation of enaminones by halo acid and DMSO

Metal free oxidative halogenation of N-aryl enaminones has been demonstrated using a DMSO–halo acid combination under mild reaction conditions. The present method is a straightforward approach and is also applied for the synthesis of chromenone derivatives in excellent yields.

DMSO as a Switchable Alkylating Agent in Heteroarene C-H Functionalization

Herein, we report a novel strategy for the activation of DMSO to act as a versatile alkylating agent in heteroarene C-H functionalization. This direct, simple, and mild switch between methylation/trideuteromethylation and methylthiomethylation of heteroarenes was achieved under reagent-controlled photoredox catalysis conditions. The proposed mechanism is supported by both experimental and computational studies.

Ligand-Exchange Processes on Solvated Lithium Cations: DMSO and Water/DMSO Mixtures

Solutions of LiClO(4) in solvent mixtures consisting of dimethylsulfoxide (DMSO) and water, or DMSO and gamma-butyrolactone, were studied by (7)Li NMR spectroscopy (for complexation by cryptands in gamma-butyrolactone as a solvent, see: E. Pasgreta, R. Puchta, M. Galle, N. J. R. van Eikema Hommes, A. Zahl, R. van Eldik, J. Incl. Phen., 2007, 58, 81-88). Chemical shifts indicate that the Li(+) ion is coordinated by four DMSO molecules. In the binary solvent mixture of water and DMSO, no selective solvation is detected, thus indicating that on increasing the water content of the solvent mixture, DMSO is gradually displaced by water in the coordination sphere of Li(+). The ligand-exchange mechanism of Li(+) ions solvated by DMSO and water/DMSO mixtures was studied using DFT calculations. Ligand exchange on [Li(DMSO)(4)](+) was found to follow a limiting associative (A) mechanism. The displacement of coordinated H(2)O by DMSO in [Li(H(2)O)(4)](+) follows an associative interchange mechanism. The suggested mechanisms are discussed in reference to available experimental and theoretical data.

Fast wave activity in the rat rhinencephalon: elicitation by the odors of phytochemicals, organic solvents, and a rodent predator

Recent research has shown that bursts of approximately 20 Hz fast waves are elicited in rhinencephalic cortex in rats by the odors of a number of different organic solvents and of components of the secretions of predators such as the weasel and the fox. We now show that a number of phytochemicals (benzyl alcohol, carvacrol, eucalyptol, and salicylaldehyde) will elicit fast wave bursts of about 20 Hz in the rat pyriform cortex. Additional organic solvents (carbon tetrachloride, chloroform, diethyl ether, 1, 2-dimethoxyethane, n-heptane, mesitylene, methylcyclohexane, and commercial gasoline and kerosene, but not N,N-dimethylformamide or dimethyl sulfoxide) and another component of fox secretions (isopentenylmethyl sulfide) were also effective. Many of these compounds will also elicit fast wave bursts of about 20 Hz in the dentate gyrus. The effectiveness of benzyl alcohol, camphor, carvacrol, eucalyptol, isopentenylmethyl sulfide, 2-propylthietane, salicylaldehyde, toluene, and trimethylthiazoline (all of which elicit rhinencephalic fast waves in rats) in suppressing feeding in various small herbivores suggests that the recording of odor-induced rhinencephalic fast waves may provide an easy means of identifying new antifeedants. We found no evidence that the bursts of 20-Hz activity seen in the rat rhinencephalon were kindling-induced seizure-like reactions of the olfactory brain to the vapors of toxic chemicals.

Poly-L-methionine sulfoxide: a biologically inert analogue of dimethyl sulfoxide with solubilizing potency

Poly-L-methionine sulfoxide is a water-soluble polymer containing the sulfoxide moiety. The preparation and radiolabeling of this polymer is described and its bioeffects are compared with those of dimethyl sulfoxide. Poly-L-methionine sulfoxide is similar to dimethyl sulfoxide in that it is a potent solubilizer of lipophilic compounds in water. Although the partition coefficient of poly-L-methionine sulfoxide in 1-octanol-water is only 20 times lower than that of dimethyl sulfoxide, it was found not to penetrate into intracellular spaces. In contrast to dimethyl sulfoxide, poly-L-methionine sulfoxide and L-methionine sulfoxide were found to be ineffective in inducing differentiation in murine erythroleukemia cells and inhibiting differentiation of avian neural crest cells, suggesting that compounds effective in these processes must have the ability to penetrate into cells or membrane proteins. Overall lack of bioactivity of poly-L-methionine sulfoxide, combined with low toxicity (2 g/kg, iv, in the mouse with no effect), makes this compound a suitable inert solubilizer and carrier for lipophilic drugs.