Activated sulfahydantoin as Boc-glycine enolate equivalent: highly diastereoselective α-hydroxyalkylation and application to the synthesis of aldopentonate analogues

N-Boc-activated sulfahydantoin can be seen as glycine enolate equivalent. It appeared as a convenient starting material for the stereocontrolled preparation of threonine homologues through an alkaline syn aldolization involving a Boc migration. The methodology allowed the one-pot preparation of constrained analogues of polyoxamic acid.     

Microwave-assisted multi-step synthesis of novel pyrrolo-[3,2-c]quinoline derivatives

A new approach for the synthesis of original substituted pyrrolo-[3,2-c]quinoline derivatives using microwave-assisted chemistry is described. The use of microwave activation in this synthesis resulted in high yielding and clean steps. The key step for introducing diversity is the amination or the Pd-catalyzed cross-coupling of an imidoyl chloride derivative, obtained in a straightforward manner and in good yield.     

IR studies in the substituted benzaldehyde series provide a new definition of sigma-plus constants of ionic substituents

Fourier-transform IR frequencies nu(C=O) and integrated intensities A(C=O) of the carbonyl groups of a series of benzaldehydes (53 compounds) have been measured in dimethyl sulphoxide. Excellent and satisfactory correlations have been found between nu(C=O) and sigma(+) substituent constants of the m- and p-substituted compounds. Diortho-substituted compounds deviate strongly from the correlation lines because of the steric ortho-effects mainly. sigma(+) constants of ionic substituents (10 examples) have proved satisfactorily valid in the series studied.     

Decomposition of Dissolved Methylene Blue in Water Using a Submerged Arc Between Titanium Electrodes

Low voltage, low energy submerged pulsed arcs between Ti electrodes with a pulse repetition rate of 100 Hz, energies of 2.6–192 mJ and durations of 10–40 μs, followed by aging in the dark, were used to decompose 10 mg/l methylene blue (MB) contamination in 40 ml aqueous solutions, with and without the addition of 0.5 % H₂O₂. The impact of the arc treatment on the MB removal ratio (C₀–C_ta)/C₀ was considered as a function of aging time t_a, where C₀ and C_ta are the MB concentrations initially and after t_a (the time needed to complete removal of MB after cessation of exposure of the arc). Particles eroded from the electrodes during the discharge enabled MB decomposition during aging. The particles were studied by XRD, XPS and Raman analysis, and titanium oxides and peroxides were found. MB decomposition during aging is explained by the formation of a surface layer of titanium peroxide that forms by the interaction of titanium dioxide with H₂O₂, which produce radicals which oxidize the MB. The 99.6 % MB removal yield (G_99.6 = 90 g/kWhr) of the submerged pulsed arc process with Ti electrodes and addition of 0.5 % H₂O₂ was more than 60 times larger than obtained at 50 % removal with other plasma methods.