丙烯酸β-羧乙酯-苯乙烯共聚物缩合异烟肼的合成及其水解释放研究

<正> 大分子载体药物是精细高分子合成的一个重要研究领域,作为药物载体的大分子骨架需有良好的生物相容性及控制释放能力。本文采用具有较长柔性侧支链的丙烯酸β-羧乙酯(APA)-苯乙烯(St)共聚物作载体,并通过羧基与抗结核药物异烟肼反应,制备出毒性较低并能控制释放的大分子载体异烟肼药物。     

药物分子与β—环糊精络合的光谱研究

环糊精能在水溶液中包络尺寸合宜的分子至其疏水性的环状腔体中,包络过程被用于增大有机分子的水溶性,用作酶的模拟,用于色谱学、荧光光度法和室温磷光法等。β-环糊精(β-CD)是最通用的一种,其内腔直径为0.7nm。     

Normal-phase high-performance liquid chromatographic separations using ethoxynonafluorobutane as hexane alternative. II. Liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry applications with methanol gradients

We have reported recently that high-speed normal-phase (NP) HPLC separations of a broad range of organic compounds can be performed on cyano columns using gradients of methanol in hexane-like solvent-ethoxynonafluorobutane (ENFB), available commercially. In this communication, we demonstrate that atmospheric pressure chemical ionization (APCI) in combination with mass spectrometry (MS) can be effectively used for detection in such separations. The efficiency of APCI under conditions studied has also been compared to the efficiency of traditional electrospray ionization (ESI) in combination with MS for reversed-phase (RP) HPLC of the same compounds. The compounds included in this study were steroids, benzodiazepines, and other central nervous system-active substances, nonsteroidal anti-inflammatory drugs, tricyclic antidepressants, and beta-adrenergic blocking agents. Non-polar compounds were found to respond stronger when APCI-MS technique was used, whereas APCI and ESI ionization efficiencies were comparable when polar substances were studied. The combination of normal-phase HPLC separation conditions with mass spectral detection may expand the range of LC-MS applications traditionally associated with reversed-phase HPLC and ESI-MS detection.     

Silver (I)-promoted asymmetric halohydrin reaction of chiral N-enoyl-2-oxazolidinones: scope and limitations

The halohydrin reaction of chiral N-enoyl-2-oxazolidinones 1 by halogen (Br₂/I₂) and water were efficiently carried out in aqueous organic solvent promoted by silver(I) with high anti- and regioselectivity and moderate to good diastereoselectivities. The alkenoyl, cinnamoyl and electron-deficient cinnamoyl substrates smoothly underwent bromohydrin reaction in aqueous acetone but no iodohydrin reaction, where as electron-rich cinnamoyl substrates preferred to undergo iodohydrin reaction in aqueous acetone with moderate diastereoselectivity and enhanced diastereoselectivity was observed in aqueous THF.     

Hydrolytic and transglycosylation reactions of N-acyl modified substrates catalysed by β-N-acetylhexosaminidases

The hydrolytic and transglycosylation capabilities of 35 fungal β-N-acetylhexosaminidases with p-nitrophenyl 2-amino-2-deoxy-β-d-glucopyranoside and its four N-acyl derivatives (CHO, COCH₂OH, COCH₂CH₃, COCF₃) as substrates were tested. The preparation of four novel p-nitrophenyl disaccharides from these unnatural substrates catalysed by enzymes from Aspergillus oryzae, Penicillium oxalicum and Talaromyces flavus represents a considerable extension of the synthetic potential of glycosidases.     

Synthesis of cyclopentane building blocks via an intramolecular CH insertion reaction of a chiral pool derived α-diazo-γ-hydroxy-β-ketosulfone

A highly functionalized cyclopentanone building block 13 was prepared by a facile Rh-catalyzed intramolecular CH insertion reaction of an enantiopure α-diazo-γ-hydroxy-β-ketosulfone 12, in turn derived from an α-hydroxy acid 2. A cyclic γ-hydroxy vinyl sulfone 16 was also prepared from 13.     

A simple and efficient one-step, regioselective, enzymatic glucosylation of arbutin by α-glucosidase

4-Hydroxyphenyl-β-isomaltoside has been synthesized by α-glucosidase assisted transglycosylation between arbutin as acceptor and sucrose as donor molecules, respectively. Optimum conditions for the transglucosylation reaction were 40 °C for 20 h with 10 mM arbutin and 1.5 M sucrose in a 100 mM sodium citrate/phosphate buffer at pH 5.0. The new glucoside was obtained in a 50% molar yield with respect to arbutin.     

Probing in vitro digestion at oil–water interfaces

Interfacial layers have been widely applied to study the formation and stability of emulsion-based systems. However, the application of isolated interfaces to address digestibility of emulsions is often limited because of the complexity of experimental methods and results. This review summarizes the latest developments in analytical methods and literature data on effects of digestion on interfacial layers. Particular emphasis is given to understand the changes on interfacial magnitudes during oral, gastric, and duodenal digestion, either applied separately or sequentially. Limitations of interfacial aspects and key factors that influence emulsion microstructure in bulk and lipid digestion are identified. Understanding the behavior of interfacial layers upon gastrointestinal digestion promotes an accurate tracking of the physiological fate of emulsions.     

A DFT study of lithium battery materials: application to the β-VOXO4 systems (X=P, As, S)

VOXO₄ systems have been considered as potential lithium battery electrodes. They mainly present two distinct structural types: the tetragonal “α” type with a two-dimensional framework, and the three-dimensional orthorhombic “β”. DFT calculations were performed on this latter system for several β-Li_xVOXO₄ compounds (x=0, 1; X=P, As, S). They allowed to propose structural models for VOAsO₄ and LiVOSO₄, not fully crystallographically well described yet. Based on an experimental model of two-phase processes, these calculations led also to a good simulation of electrochemical potential values. A density of states analysis put in evidence the “inductive effect” and the role played by (XO₄)ⁿ⁻ groups inside the host frameworks on these potentials.     

Stereoselective synthesis of (Z)-γ-cyano-β-perfluoroalkyl-β,γ-unsaturated esters

(Z)-γ-Cyano-β-perfluoroalkyl-β,γ-unsaturated esters have been synthesized by the reaction of perfluoroacylated phosphonates with organozinc reagent in 50-71% (three steps) yields.