甲氧基修饰的大孔交联树脂对苯酚的吸附机理

由大孔氯甲基化聚苯乙烯合成了含有悬挂醚键的甲氧基修饰的大孔交联树脂.通过化学分析(氯含量的测定)、红外光谱和元素分析等手段,确证甲氧基负载在聚苯乙烯骨架上,负载量为4.10mmol/g.测定了这种树脂对正己烷中苯酚的吸附等温线,表明其对正己烷中苯酚的吸附是放热的,随着温度的升高,吸附量逐渐降低,且吸附等温线可拟合成直线.通过吸附焓的计算、不同条件下吸附等温线的比较以及理论计算等方法,确证氢键是甲氧基修饰的大孔交联树脂吸附正己烷中苯酚的主要驱动力,树脂骨架上负载的醚氧原子与苯酚的酚羟基氢原子形成了强烈氢键.     

一些含氟单体的合成及其聚合反应的初步研究

合成了含氟单体3-氧杂全氟戊烷-1,5-二磺酰溴(3),N-烯丙基-2-(ω-碘-n-全氟烷氧基)-1,1,2,2-四氟乙磺酰胺(16～18).初步研究了含氟单体3与非共轭二烯的聚合反应、连二亚硫酸钠引发的含氟单体16～18的聚合反应以及α,ω-全氟烷基二碘代烷22,23与非共轭端二烯的聚合反应,得到了相应的含氟聚合物或寡聚物.     

In vitro and in vivo studies of androst‐4‐ene‐3,6,17‐trione in horses by gas chromatography–mass spectrometry

This paper describes the application of gas chromatography–mass spectrometry (GC‐MS) for in vitro and in vivo studies of 6‐OXO in horses, with a special aim to identify the most appropriate target metabolite to be monitored for controlling the administration of 6‐OXO in racehorses. In vitro studies of 6‐OXO were performed using horse liver microsomes. The major biotransformation observed was reduction of one keto group at the C3 or C6 positions. Three in vitro metabolites, namely 6α‐hydroxyandrost‐4‐ene‐3,17‐dione (M1), 3α‐hydroxyandrost‐4‐ene‐6,17‐dione (M2a) and 3β‐hydroxyandrost‐4‐ene‐6,17‐dione (M2b) were identified. For the in vivo studies, two thoroughbred geldings were each administered orally with 500 mg of androst‐4‐ene‐3,6,17‐trione (5 capsules of 6‐OXO_®) by stomach tubing. The results revealed that 6‐OXO was extensively metabolized. The three in vitro metabolites (M1, M2a and M2b) identified earlier were all detected in post‐administration urine samples. In addition, seven other urinary metabolites, derived from a further reduction of either one of the remaining keto groups or one of the remaining keto groups and the olefin group, were identified. These metabolites included 6α,17β‐dihydroxyandrost‐4‐en‐3‐one (M3a), 6,17‐dihydroxyandrost‐4‐en‐3‐one (M3b and M3c), 3β,6β‐dihydroxyandrost‐4‐en‐17‐one (M4a), 3,6‐dihydroxyandrost‐4‐en‐17‐one (M4b), 3,6‐dihydroxyandrostan‐17‐one (M5) and 3,17‐dihydroxyandrostan‐6‐one (M6). The longest detection time observed in urine was up to 46 h for the M6 metabolite. For blood samples, the peak 6‐OXO plasma concentration was observed 1 h post administration. Plasma 6‐OXO decreased rapidly and was not detectable 12 h post administration. Copyright © 2009 John Wiley & Sons, Ltd.     

Characterization of anti‐Coxsackie virus B3 constituents of Radix Astragali by high‐performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry

To profile the anti‐Coxsackie virus B3 constituents of Radix Astragali, an HPLC‐DAD‐MSⁿ analytical method, combined with an in vivo test, has been developed to identify the constituents of the active part, which has been demonstrated to have potency to inhibit the proliferation of virus in cardiac muscle, alleviate infraction in heart and elevate the survival rate of the animal. By comparing their retention time and MS data with those obtained from the authentic compounds and the published data, a total of 19 compounds, including 11 isoflavonoids and eight saponins, were identified, among which one pterocarpane glucoside was reported for the first time. The present study provides an approach to rapidly screening bioactive constituents in traditional Chinese medicines. Copyright © 2010 John Wiley & Sons, Ltd.     

Molecularly imprinted polymer coated on stainless steel fiber for solid-phase microextraction of chloroacetanilide herbicides in soybean and corn

A molecularly imprinted polymer (MIP) with metolachlor as template was firstly coated on stainless steel fiber through chemical bonding strategy to solve the fragility problem of silica fiber substrate for solid-phase microextraction. The surface pretreatment of stainless steel fiber and the polymerization conditions were investigated systematically to enhance the preparation feasibility and MIP coating performance, and then a porous and highly cross-linked MIP coating with 14.8-μm thickness was obtained with over 200 times re-usability which was supported by non-fragile stainless steel fiber adoption. The MIP coating possessed specific selectivities to metolachlor, its metabolites and other chloroacetanilide herbicides with the factors of 1.1–4.6. Good extraction capacities of metolachlor, propisochlor and butachlor were found with MIP coating under quick adsorption and desorption kinetics, and the detection limits of 3.0, 9.6 and 38 μg L⁻¹ were achieved, respectively. Moreover, the MIP-coated stainless steel fiber was evaluated for trace metolachlor, propisochlor and butachlor extraction in the spiked soybean and corn samples, and the enrichment factors of 54–60, 27–31 and 15–20 were obtained, respectively.     

Synthesis,structure and biological activity of diorganotin derivatives with pyridyl functionalized bis(pyrazol‐1‐yl)methanes

Three pyridyl functionalized bis(pyrazol‐1‐yl)methanes, namely 2‐[(4‐pyridyl)methoxyphenyl] bis(pyrazol‐1‐yl)methane (L¹), 2‐[(4‐pyridyl)methoxyphenyl]bis(3,5‐dimethylpyrazol‐1‐yl)methane (L²) and 2‐[(3‐pyridyl)methoxyphenyl]bis(pyrazol‐1‐yl)methane (L³) have been synthesized by the reactions of (2‐hydroxyphenyl)bis(pyrazol‐1‐yl)methanes with chloromethylpyridine. Treatment of these three ligands with R₂SnCl₂ (R = Et, n‐Bu or Ph) yields a series of symmetric 2:1 adducts of (L)₂SnR₂Cl₂ (L = L¹, L² or L³), which have been confirmed by elemental analysis and NMR spectroscopy. The crystal structures of (L²)₂Sn(n‐Bu)₂Cl₂·0.5C₆H₁₄ and (L³)₂SnEt₂Cl₂ determined by X‐ray crystallography show that the functionalized bis(pyrazol‐1‐yl)methane acts as a monodentate ligand through the pyridyl nitrogen atom, and the pyrazolyl nitrogen atoms do not coordinate to the tin atom. The cytotoxic activity of these complexes for Hela cells in vitro was tested. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis,Spectroscopy, Crystal Structure Determination,and Quantum Chemical Calculations of BODIPY Dyes with Increasing Conformational Restriction and Concomitant Red‐Shifted Visible Absorption and Fluorescence Spectra

Starting from the conformationally unconstrained compound 3,5‐di‐(2‐bromophenoxy)‐4,4‐difluoro‐8‐(4‐methylphenyl)‐4‐bora‐3a,4a‐diaza‐s‐indacene ( 1 ), two BODIPY dyes ( 2 and 3 ) with increasingly rigid conformations were synthesized in outstanding total yields through palladium catalyzed intramolecular benzofuran formation. Restricted bond rotation of the phenoxy fragments leads to dyes 2 and 3 , which absorb and fluoresce more intensely at longer wavelengths relative to the unconstrained dye 1 . Reduction of the conformational flexibility in 2 and 3 leads to significantly higher fluorescence quantum yields compared to those of 1 . X‐ray diffraction analysis shows the progressively more extended planarity of the chromophore in line with the increasing conformational restriction in the series 1 → 2 → 3 , which explains the larger red shifts of the absorption and emission spectra. These conclusions are confirmed by quantum chemical calculations of the lowest electronic excitations in 1 , 1a , 2 , 2a , 3 and dyes of related chemical structures. The effect of the molecular structure on the visible absorption and fluorescence emission properties of 1 , 1a , 2 , 2a , 3 has been examined as a function of solvent by means of the new, generalized treatment of the solvent effect (J. Phys. Chem. B 2009 , 113, 5951–5960). Solvent polarizability is the primary factor responsible for the small solvent‐dependent shifts of the visible absorption and fluorescence emission bands of these dyes.