THE SULFUR (11)-NITROGEN BOND. PART IV1. AMINOSULFENATES

Abstract

Aminosulfenates R₂NSOR' have been prepared from aminosulfenyl chlorides and tin alkoxides. They form sulfenyl chlorides with chlorosilanes, bisaminosulfides with secondary amines and polysulfides with thiols.     

A New Norditerpene from Miliusa balansae Finet et Gagnep

The plant Miliusa balansae Finet et Gagnep. is used in Chinese folk medicine for different symptom such as gastropathy and glomerulonephropathy. There is no report about its chemical investigation. In this study a new norditerpene with novel skeleton, named miliusate (1) was isolated, and its structure was established by spectral evidence.Compound 1 was obtained as white flaky crystal, mp 89-91(C; Its molecular formula C20H26O5 was provided by quasi-molecular ion [M+H]+ at m/z 347.17970 (c…     

A new anthraquinone and eight constituents from Hedyotis caudatifolia Merr. et Metcalf: isolation,purification and structural identification

Hedyotis caudatifolia Merr. et Metcalf. (HC), a folk medicine in Yao nationalities areas in China, was used to investigate the chemical constituents. Through silica gel and Sephadex LH-20 column chromatography, nine compounds were isolated and purified. By physical and chemical properties, IR, MS (EI-MS, high resolution EI-MS), 1D NMR (¹H NMR, ¹³C NMR) and 2D NMR (HSQC, ¹H–¹H COSY, HMBC), their structures were identified as β-sitosterol (1), stigmasterol (2), scopolin (3), 2-hydroxy-1,7,8-trimethoxyanthracene-9,10-dione (4), oleanolic acid (5), ursolic acid (6), methyl barbinervate (7), β-daucosterol (8) and p-Hydroxybenzoic acid (9). These compounds were isolated from HC for the first time, and 4 a new anthraquinone whose biological activities are worth to be investigated in future. These compounds may contribute to the HC’s pharmacological effects on treating diseases, and may be used as candidates for control index in establishing the quality control standard of HC.     

The influence of the modification of carbonaceous materials on their catalytic properties in SCR-NH3. A short review

Carbonaceous catalysts are promising materials for the low-temperature (< 523 K) process of NO reduction with ammonia. Based on literature and own experience of the authors, this review focuses on the possibilities to enhance their catalytic performance. It may be increased by the introduction of oxygen or nitrogen functionalities. So obtained materials may be used in SCR-NH₃ either as catalysts or supports for transition metals oxides/hydroxides. Oxygen functionalities increase activity only to a small extent, but are necessary to prepare an efficient MeO_x/AC catalyst. Nitrogen surface species lead to a considerable increase in DeNO_x activity, as well as stability towards their oxidation to CO₂. As the most efficient active components, oxides of V, Mn, Fe and Cu were found. H₂O leads to the decrease of activity but for some catalysts additionally to the increase in selectivity. The understanding of SO₂ influence needs more experimental data. There still are several open questions concerning more detailed mechanistic studies, and especially the role of nitrogen functionalities, H₂O and SO₂.     

三波长-分光光度法测定大叶落地生根中总黄酮的含量

以木犀草素-7-O-β-D-葡萄糖苷为对照品、AlCl3作为显色剂,建立了三波长分光光度法测定大叶落地生根中总黄酮含量的方法。结果显示,总黄酮在0~0.01g/L范围内呈良好的线性关系,相关系数r=0.9999,平均回收率为101.4%,RSD=3.7%(n=4)。该方法可校正混浊背景倾斜度的影响,消除重叠吸收曲线的干扰,适用于植物中总黄酮的测定。     

Identification of the convective instability in a multi-component solution by 3D simulations

Three-dimensional calculations have been done to simulate the onset of convective motion in ternary nondilute solution under phase transition conditions. The process is considered for Rayleigh number in the range $[1\times {10}^3,1.4\times {10}^4]$, where subcritical convective motion with hexagonal flow pattern is identified. The results are in good agreement with the linear and finite amplitude theory of hydrodynamics instability. To cite this article: V.V. Kolmychkov et al., C. R. Mecanique 333 (2005).     

Groupe Des Inversibles Et Rayon Spectral Dans Les Algèbres Topologiques

We deal with the relationship between the spectral radius and the topological bihaviour of the group of invertible elements in a topological algebra, introducing accordingly several types of (generalized Q-) algebras. We then give properties and characterizations of such algebras. Applications to weighted algebras as well as several classes of examples are provided.

     

Zinc-porphyrin sensitized reduction of simple and functional quinones in vesicle systems

Changes of the surfactant vesicle sizes and of the efficiency of the photoredox reaction between various solubilized Zn porphyrins and duroquinones upon incorporation of the chromophore or upon addition of salts have been examined by quasi-elastic light scattering and laser photolysis techniques. The yields of porphyrin cation and duroqumone anion radicals appear to be independent of the nature of the porphyrin-qumone system. Addition of salts influences both the yield and the ejection of porphyrin cations from the vesicles by screening up the surface charge.     

Détermination de la réponse asymptotique d'une structure anélastique sous chargement thermomécanique cycliqueDetermination of the asymptotic response of a structure under cyclic thermomechanical loading

A method for the solution of cyclic thermomechanical nonlinear problems is presented: it is a Direct Cyclic Method which is an alternative approach to classical methods. It consists in directly seeking the asymptotic response of an inelastic structure subjected to a periodic thermomechanical loading without following the loading path. It is based on the Large Time Increment Method, the periodicity of the limit state and the Fourier transform. To cite this article: M.H. Maitournam et al., C. R. Mecanique 330 (2002) 703–708.