Monoterpenoid chemistry. Part 3.. Stereoselective synthesis of the major oxygenated metabolites of trans-sobrerol

The stereoselective synthesis of the major oxygenated metabolites of trans-sobrerol ( 1 ) in optically active and/or racemic form is described.     

Spontaneous symmetry breaking in an O(2) invariant scalar theory

A simple variational principle for an O(2) invariant scalar theory, within the framework of gaussian wave functionals, is presented. The conditions for the occurrence of spontaneous symmetry breaking are discussed. The limits of validity of the gaussian approximation are also analyzed in detail.     

Fluoride ion induced reactions of organosilanes with electrophiles

Benzyl- 4-picolyl- and phenylallyl(trimethyl)silanes react with electrophiles in the presence of KF/18-crown-6 or silica-TBAF under mild conditions.     

Thermodynamic characterization of the acetylacetone-trichloroethylene system

Delfini, M., Gironi, F. and Variali, G., 1984. Thermodynamic characterization of the acetylacetone-trichloroethylene system. Fluid Phase Equilibria, 18: 69–82.Vapor-liquid equilibria have been measured for the system acetylacetone-trichloroethylene at 100, 200, 400 and 760 mm Hg. The influence of trichloroethylene on the keto-enol equilibrium of acetylacetone has been elucidated by ¹H NMR spectroscopy.A semiempirical model taking into account the “true” chemical species involved (the enol and keto tautomers of acetylacetone, and trichloroethylene) is used for thermodynamic reduction of the experimental data.     

Side-chain silylation of heterocyclic derivatives. The sythesis of 3-methyl-5-(trimethylsilylmethyl)-1,2,4-oxa-diazole and the atttempted synthesis of 3-methyl-4-nitro-5(trimethylsilymethyl)isoxazole via organolithium reagents

Silylation of activated heterocyclic systems via treatment with organolithium reagents followed by coupling with Me₃SiCl, leads to the expected product in the case of 3,5-dimethyl-1,2,4-oxadiazole, whereas for 3,5-dimethyl-4-nitroiso-xazole the predominant reaction is addition of the lithiating agent, to give after work-up 3,5-dimethyl-5-butyl-4-nitro-4,5-isoxazoline.     

Equation of state data for iron at pressures beyond 10 Mbar

We present equation of state points for iron, in the pressure range 10-45 Mbar, the first obtained with laser-driven shock waves. The experiment has been performed with the high energy laser Phebus, optically smoothed with Kinoform phase plates. Our results double the set of existing experimental data at very high pressures showing good agreement with the predictions of the quotidian equation of state model and with previous results.     

Some molecular aspects of the radiation-induced oxidative degradation of glutathione

Glutathione (GSH) is well known to have an important role as natural antioxidant. Some aspects of GSH degradation following the capture of water primary radicals in aerated or deaerated medium were investigated after -irradiation and by pulse radiolysis.___TAGSTART___BR___TAGEND___ Some relevant reactions involved in the GSH oxidation mechanism, leading to GSOO-related products, were evidenced by pulse radiolysis experiments.___TAGSTART___BR___TAGEND___ From the quantitative determinations of the GSH degradation and the GSSG formation, useful indications on the fate of thiyl radicals (GS), the most preminent sulfur centred intermediates, were drawn out in anaerobic and aerobic conditions.