Electrochemical Oxidation of Sanguinarine and of Its Oxidation Products at a Glassy Carbon Electrode – Relevance to Intracellular Effects

The electrochemical behavior of sanguinarine, a quaternary benzophenanthridine glycoside alkaloid with antimicrobial, anti‐inflammatory, antioxidant and/or immune‐stimulatory activities, was studied at a glassy carbon electrode using cyclic, differential pulse, and square wave voltammetry. The oxidation of sanguinarine is a quasireversible, diffusion‐controlled process and occurred in a cascade mechanism with the formation of several oxidation products which adsorbed at the electrode surface. The oxidation of sanguinarine is pH dependent and involves the transfer of the same number of electrons and protons. The adsorbed sanguinarine oxidation products are reversibly oxidized at the glassy carbon electrode surface and their oxidation for a wide range of pHs was also studied by differential pulse and square wave voltammetry. A mechanism for the oxidation of sanguinarine at glassy carbon electrode is proposed.     

Representations of quantum permutation algebras

We develop a combinatorial approach to the quantum permutation algebras, as Hopf images of representations of type π:A_s(n)→B(H). We discuss several general problems, including the commutativity and cocommutativity ones, the existence of tensor product or free wreath product decompositions, and the Tannakian aspects of the construction. The main motivation comes from the quantum invariants of the complex Hadamard matrices: we show here that, under suitable regularity assumptions, the computations can be performed up to n=6.     

New application of AAO template: a mold for nanoring and nanocone arrays

Nanoring and nanocone arrays were prepared by conical openings of nanopores in as-prepared AAO film as a mold.     

O2 chemistry of dicopper complexes with alkyltriamine ligands. Comparing synergistic effects on O2 binding

Two dicopper(I) complexes containing tertiary N-methylated hexaaza ligands which impose different steric constraints to the Cu ions have been synthesized, and their reactivity toward O2 has been compared with a mononuclear related system, highlighting the importance of cooperative effects between the metal centers in O2 activation.     

Catalytic ability of a cationic Ru(II) monochloro complex for the asymmetric hydrogenation of dimethyl itaconate and enamides

The synthesis of two Ru chloro complexes, Ru(III)Cl(3)(bpea), 1, and cis-fac-Delta-[Ru(II)Cl{(R)-(bpea)}{(S)-(BINAP)}](BF(4)), cis-fac-Delta-(R)-(S)-2, (bpea = N,N-bis(2-pyridylmethyl)ethylamine; (S)-BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl), is described. Complex 2 is characterized in solution through UV-vis, cyclic voltammetry (CV), and 1D and 2D NMR spectroscopy. X-ray diffraction analysis indicates that in the solid state it possesses the same structure as in solution, as expected for a low-spin d(6) Ru(II)-type complex. The molecular structure of cis-fac-Delta-(R)-(S)-2, consists of a nonsymmetric complex, where the Ru metal center has a significantly distorted octahedral-type coordination because of the bulkiness of the (S)-BINAP ligand. cis-fac-Delta-(R)-(S)-2 has a remarkable catalytic performance at P = 6.8 atm of H2 and T = 70 degrees C toward the hydrogenation of prochiral double bonds both from efficiency and from stereoselectivity viewpoints. As an example, prochiral olefins of technological interest such as dimethyl itaconate, methyl 2-acetamidoacrylate or methyl 2-acetamidocinnamate are catalytically hydrogenated by cis-fac-Delta-(R)-(S)-2, with conversions higher than 99.9% and ee > 99. Furthermore, cis-fac-Delta-(R)-(S)-2, also catalyzes the selective hydrogenation of beta-keto esters, although the reaction rates are lower than those found with the former substrates.     

Synthesis and conformational analysis of new cyclobutane-fused nucleosides

[structure: see text]. A stereselective synthesis of 3-oxabicyclo[3.2.0]heptane nucleoside analogues, which were designed as conformational mimics of the anti-HIV agents 2',3'-didehydro-2',3'-dideoxythimidine (stavudine, d4T) and 2',3'-didehydro-2',3'-dideoxyadenosine (d4A), is described. The target compounds were prepared by condensation of a common intermediate bicyclic acetate, derived from a homochiral 2(5H)-furanone, with pyrimidine and purine bases under modified Vorbrüggen conditions. The conformational behavior of the synthesized nucleoside analogues was studied by NMR spectroscopy and X-ray crystallography.     

Majorization for certain classes of analytic functions using multiplier transformation

In the present paper we investigate the majorization properties for certain classes of multivalent analytic functions defined by multiplier transformation. Moreover, we point out some new or known consequences of our main result.