Anti-inflammatory chromone alkaloids and glycoside from Dysoxylum binectariferum

Herein we report isolation of a new chromone alkaloid chrotacumine K (12) from fruits and a chromone glycoside schumaniofioside A (13) from leaves of Dysoxylum binectariferum Hook f. Schumaniofioside A is reported for the first time from Meliaceae family. Other known alkaloids isolated include rohitukine (1) and chrotacumine E (6). The structure of new alkaloid 12 was elucidated on the basis of extensive 1D and 2D NMR analysis, synthesis and chemical hydrolysis. Chemically, chrotacumine K (12) is a 3′-O-acetyl rohitukine which on chemical or enzymatic hydrolysis produces rohitukine. The new alkaloid 12 is also present in seeds and stem-barks of this plant. The glycoside schumaniofioside A (13) is present only in leaves, and in abundance (～1% w/w of dried leaves). The isolated compounds and extracts were evaluated for in vitro effect on the proinflammatory cytokines (TNF-α and IL-6) in human monocytic THP-1 cells. The alkaloid 12 displayed potent inhibition (57%) of TNF-α at 0.3 µM, and was non-toxic to THP-1 cells up to 40 µM, indicating its excellent therapeutic window. Furthermore, a nitrobenzoyl ester analog 15e showed better inhibition of IL-6 than parent natural product chrotacumine K.     

Mesoporous polymer-coated PAN beads for environmental applications: fabrication,characterisation and uranium adsorption studies

Adsorption of U(VI) and other heavy metals on millimetre sized polymer-coated polyacrylinitrile (PAN) beads was investigated. PAN was used as scaffolds for the polymer layer thus producing porous material of high surface area, improved mechanical strength and improved adsorption capabilities. Extensive U(VI) adsorption studies were undertaken and results modelled using different kinetic and equilibrium models. Parameters including thermodynamic parameters were evaluated. Sorbent capacities were assessed as 124, 16, and 33 mg g^?1 for PCP, SPP and Dowex at 60 °C respectively. U(VI) adsorption mechanism for these adsorbents was postulated. Recovered uranium may be used for production of cheap electricity.     

Compounds of potassium and tin(II) with diiminopyridine ligands: EPR spectroscopy and theoretical study

Potassium and tin(II) derivatives of the paramagnetic forms of the redox-active 2,6-bis(2,6-diisopropylphenyliminomethyl)pyridine were synthesized and studied by means of EPR spectroscopy. It was shown that the reaction with metallic potassium involves the three-electron step reduction of the organic ligand to form a radical anion, dianion, and trianion radical, respectively. The reactions of the tin(II) diiminopyridine derivatives with metallic magnesium give complexes comprising the radical anion form of the ligand and a low-valence metal center. The geometries of the paramagnetic products and their spin density distributions were explored in terms of the density functional theory.     

Novel approach to the synthesis of istaroxime

Istaroxime 1, a novel cardiotonic agent with high efficiency and low toxicity was synthesized from dehydroepiandrosterone 2 using a novel approach that included epoxidation, ring-opening, substitution, and oximation. The new protocol without gas protection was milder than the reported approaches. The overall yield of the method was 24.1%.     

Decomposition of pentaammineaquacobalt(III) perchlorate under laser radiation action

Photolytic decomposition of the complex [Co(NH₃)₅(H₂O)](ClO₄)₃ under the action of a laser with a wavelength of 355 nm, which is resonant in energy to the energy of the (¹ A _1g → ¹ T _2g ) d–d transition, was studied. Decomposition of the complex is accompanied by a release of ammonia with its subsequent oxidation to nitrogen oxides and by partial cobalt reduction with the formation of the mixed cobalt(II, III) oxide Co₃O₄.     

Preparation of Ultramicroporous Materials by Fluidized-Bed Pyrolytic Deposition of Carbon in Pores of a Carbon Matrix

Samples of microporous materials were prepared by pyrolytic deposition of carbon from divinyl in a fluidized bed reactor onto carbon supports obtained from coconut and pine nut shells. The influence exerted on the adsorption capacity for CO2 by the divinyl pyrolysis temperature (in the range 600–750°С) and degree of densification (in the range 6–22%) was studied. Carbon deposition conditions ensuring the specific surface area (S_BET) lower than 5 m2 g^–1 at the adsorption capacity for СО₂ higher than 1 mmol g^–1 for both samples were found.     

Degradation of physicomechanical properties of epoxy nanocomposites with carbon nanotubes upon heat and humidity aging

The dependence of the physicomechanical properties of epoxy nanocomposites subjected to heat and humidity aging on the type of covalently functionalized carbon nanotubes and on the uniformity of their distribution in the epoxy matrix was studied. Two types of carbon nanotubes were used: those modified with carboxy and amide groups. The elastic modulus, bending deflection, and ultimate bending strength for the initial epoxy nanocomposites with carbon nanotubes and for those subjected to heat and humidity aging were determined. The epoxy binders modified with carboxylated carbon nanotubes are more resistant to the action of aging factors. The presence of aggregates of carboxylated carbon nanotubes in the epoxy matrix positively influences the preservation of physicomechanical properties of the composite subjected to heat and humidity aging. Microscopic examination revealed structural features of the epoxy nanocomposite and their effect on the resistance of the composite to the heat and humidity aging.     

Aggregatively stable suspensions of micrometer powders of doped barium cerate for electrophoretic deposition of thin-film coatings of solid-oxide fuel cells

Potentialities of the method of electrophoretic deposition of thin-film coatings based on micrometer powders of multidoped barium cerate BaCe_0.8Sm_0.19Cu_0.01O_3–δ (BCSCuO) and BaCe_0.89Gd_0.1Cu_0.01O_3–δ (BCGCuO) were considered. Micrometer powders of BCSCuO and BCGCuO were produced by the methods of solid-phase and citrate-nitrate syntheses, respectively. The dispersity, fraction composition, and electrokinetic potential of nonaqueous suspensions of these powders and the electrokinetic parameters of the electrophoretic deposition process were examined. An ultrasonic treatment and ultracentrifugation produced aggregatively stable suspensions of BCGCuO and BCSCuO micrometer particles in a mixed (70/30 vol %) isopropanol–acetyl acetone medium. These suspensions are characterized by high positive values of the zeta potential (+24 and +28 mV, respectively). Thin film coatings of the electrolyte materials BCSCuO and BCGCuO, which are of interest for the technology of medium-temperature solid-oxide fuel cells, were produced by the electrophoretic deposition onto a dense model cathode.     

Copolymers based on (<Emphasis Type="Italic">p</Emphasis>-vinylphenyl)cyclopropylmethyl chlorocinnamate and methyl methacrylate

Abstract—Copolymers of (p-vinylphenyl)cyclopropylmethyl chlorocinnamate with methyl methacrylate were prepared by radical copolymerization. The copolymerization constants were determined, and the Alfrey–Price Q–e parameters were calculated. The possibility of photochemical cross-linking of the copolymer via double bond conjugated with the carbonyl group in the chlorocinnamate moiety and via the cyclopropane ring was demonstrated. The copolymer obtained exhibits sufficiently high photosensitivity (54.5 cm² J^–1) and high refractive index (n _D ²⁰ 1.5890), which opens prospects for using it as a photosensitive base of negative photoresists and in optics.     

Synthesis of Decaborane by the Reaction of Sodium Undecaborate with Mild Organic Oxidants

New organic oxidants (aldehydes and ketones) allowing efficient synthesis of decaborane in a high yield via intermediate alkali metal salt were found. The sodium undecaborate oxidation process was refined, and new reaction stoichiometry was suggested.