基于5-芳基乙内酰脲类化合物的CoMFA和HQSAR研究

用CoMFA和HQSAR两种QSAR方法研究了50个乙内酰脲类分子的定量构效关系.本研究从构象搜索所得的低能结构出发构建化合物分子的构象, 建立CoMFA模型,并进行了全空间搜索. HQSAR本质上是一种二维的QSAR方法,与CoMFA方法相比,该方法在数据处理方面,比CoMFA方法快捷,并且可重复性好.两种方法均得到了较好分析结果, CoMFA的交叉验证相关系数q2 值为0.815, HQSAR的q2值为0.893.这些方程有力地说明了该类分子在(R,R)-N-3,5-dinitrobenzoyl-1,2-diamine型手性固定相上拆分过程中的影响因素,对今后类似拆分的实验研究提供了理论支持.     

“双一流”背景下高等农业院校有机化学基础课程教学新模式的构建及实践

The crop science of Sichuan Agricultural University is an authorized first-class discipline. As the strategic supporting department for innovative talent cultivation in agriculture and forestry major, we are facing a long-term challenge in reforming the teaching mode for basic course-organic chemistry and cultivating talented students with solid basic knowledge and strong sense of innovation. Herein a thorough survey was performing to establish the executable teaching programs for this course during the "Double-First Class Universities Plan" period. A multidimensional teaching resource library for organic chemistry course was also constructed. The new classroom teaching mode "Interest cultivation-Creative thought development-Autonomous and Cooperative learning", along with a stepwise practice teaching mode "Foundation skills-Integrated application-Innovative trial" was proposed and practiced among thirty-five majors including agriculture, forestry and veterinary, to improve the quality for innovative talent cultivation and support our first-class discipline construction. This research could probably serve as a reference for congeneric agricultural university.     

Regulation of redox balance using a biocompatible nanoplatform enhances phototherapy efficacy and suppresses tumor metastasis

Many cancer treatments including photodynamic therapy (PDT) utilize reactive oxygen species (ROS) to kill tumor cells. However, elevated antioxidant defense systems in cancer cells result in resistance to the therapy involving ROS. Here we describe a highly effective phototherapy through regulation of redox homeostasis with a biocompatible and versatile nanotherapeutic to inhibit tumor growth and metastasis. We systematically explore and exploit methylene blue adsorbed polydopamine nanoparticles as a targeted and precise nanocarrier, oxidative stress amplifier, photodynamic/photothermal agent, and multimodal probe for fluorescence, photothermal and photoacoustic imaging to enhance anti-tumor efficacy. Remarkably, following the glutathione-stimulated photosensitizer release to generate exogenous ROS, polydopamine eliminates the endogenous ROS scavenging system through depleting the primary antioxidant, thus amplifying the phototherapy and effectively suppressing tumor growth in vitro and in vivo. Furthermore, this approach enables a robust inhibition against breast cancer metastasis, as oxidative stress is a vital impediment to distant metastasis in tumor cells. Innovative, safe and effective nanotherapeutics via regulation of redox balance may provide a clinically relevant approach for cancer treatment.

Amplified oxidative stress achieved by modulating redox homeostasis with PDA–MB for highly effective synergistic phototherapy to inhibit primary tumors and metastases.     

High extraction efficiency fiber coated with calix[4] open-chain crown ether for solid-phase microextraction of polar aromatic and aliphatic compounds

The calix[4] open-chain crown ether, 5,11,17,23-tetra-tert-butyl-25,27-di(2-allyloxyethoxyl)-26,28-dihydroxycalix[4]arene was synthesized and used for preparation of solid-phase microextraction (SPME) fibers of enhanced extraction efficiency. The new SPME coating made from calix[4] open-chain crown ether and hydroxyl-terminated silicone oil was developed with the aid of vinyltriethoxylsilane as bridge using sol-gel method and cross-linking technology. The efficiency of the novel fiber in the extraction of polar aromatic and aliphatic compounds, such as phenols, alcohols, and volatile fatty acids, was also investigated. Due to the introduction of the polar open-chain crown ether in calix[4]arene molecules, the calix[4] open-chain crown ether fiber showed much better selectivity and sensitivity to these polar compounds in comparison with calix[4]arene fiber. It also had superior extraction efficiency when compared to commercial poly(dimethylsiloxane)-divinylbenzene and polyacrylate fibers. Parts per billion to parts per trillion level detection limits were achieved for most of the analytes through SPME in conjunction with GC and flame ionization detector. The linear ranges were two to four orders of magnitude, and the RSD values were below 7% for all analytes. The novel fiber was applied to determine volatile alcohols and fatty acids in wine samples. The volatile-free wine prepared in this work was used to assure similar chemical environment for analytes in both calibration solutions and in real wine samples, thus compensating for possible matrix interferences. The established internal standard method using 4-methyl-2-pentanol as internal standard showed satisfactory accuracy and precision.     

不同分子筛载体对CO加氢产物分布的影响

研究了几种小孔分子筛ＺＳＭ－５，ＨＹ，ＮａＹ及β担载ＺｒＯ２对Ｃ加氢反应的催化作用，并就产物的分布情况与担载ＺｒＯ２的硅铝中孔分子筛进行了对比研究。其中中孔分子筛分别用季铵盐和一级胺为模板剂，在水热条件和常温常压下合成；并用ＢＥＴ，ＸＲＤ，ＳＥＭ等手段表征了它们的孔道和骨架结构。另外，考察了碱金属Ｋ＾２＋，Ｎａ＾２＋对催化剂催化性能的影响。     

Effect of molecular structure on the solute-micelle and solute-stationary phase binding constants in micellar liquid chromatography

The effects of molecular structure on the solute-micelle and solute-stationary phase binding constants in micellar liquid chromatography (MLC) have been investigated. The following points have been observed. (1) There is quite a good linear relationship between the solute-micelle and solute-stationary phase binding constants in MLC with the cationic (CTAB) and anionic surfactants as the additives, which means that the contribution of physico-chemical properties of solutes on the solute-micelle and solute-stationary phase binding constants acts in a parallel way. (2) Good quantitative relationships between the solute-micelle and solute-stationary phase binding constants and the solvatochromic parameters have been obtained, which indicates that the distribution mechanism of the neutral solutes in MLC is determined via their molecular interactions. Both the cavity process and the hydrogen bond interaction play a very important role in the retention of neutral solutes in MLC. The contribution of the hydrogen bond interaction, especially the hydrogen donor ability of the solutes on those binding constants in anionic and cationic surfactant MLC, is determined in a different way. (3) Linear regression analysis of the solute-micelle and solute-stationary phase binding constants between the cationic and anionic surfactant MLC has been carried out. The obtained results suggest that the transfer of the non-polar solutes from the aqueous phase to the anionic and cationic surfactant micelles acts in a parallel way, but that of the polar solutes in a different way. A model of micelles with three different sites of solubilization, i.e., (1) the core of the micelle, (2) the surface of the micelle and (3) the palisade layer of the micelle, has been used to successfully explain the observed results. Finally, the retention behavior of solutes in MLC is compared with that in reversed-phase liquid chromatography (RP-LC). It has been observed that there is no difference in separation selectivity for the non-polar solutes between MLC and RP-LC; however, for the polar solutes, MLC provides a different separation selectivity compared to that in RP-LC.     

Synthesis of comb‐shaped poly(methyl methacrylate)‐b‐poly(polytetrahydrofuran acrylate) under 60Co γ‐ray irradiation

Comb‐shaped graft copolymers with poly(methyl methacrylate) as a handle were synthesized by the macromonomer technique in two steps. First, polytetrahydrofuran acrylate (A‐PTHF), prepared by the living cationic ring‐opening polymerization of tetrahydrofuran, underwent homopolymerization with 1‐(ethoxycarbonyl)prop‐1‐yl dithiobenzoate as an initiator under ⁶⁰Co γ irradiation at room temperature; Second, the handle of the comb‐shaped copolymers was prepared by the block copolymerization of methyl methacrylate with P(A‐PTHF) as a macroinitiator under ⁶⁰Co γ irradiation. The two‐step polymerizations were proved to be controlled with the following evidence: the straight line of ln[M]₀/[M] versus the polymerization time, the linear increase in the number‐average molecular weight with the conversion, and the relatively narrow molecular weight distribution. The structures of the P(A‐PTHF) and final comb‐shaped copolymers were characterized by ¹H NMR spectroscopy and gel permeation chromatography. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3367–3378, 2002     

POLYBINAPHTHYLS INCORPORATING (R)-2,2''''-BINAPHTHO-20-CROWN-6 AND NAPHTHYL MOITIES

Chiral polymer was synthesized by the polymerization of (R)-6,6'-bistributylstannyl-2,2'-binaphtho-20-crown-6 (M-1) with 1,4-dibromo-2,3-bisbutoxy-naphthyl (M-2) by Pd(PPh3)4 catalyzed Stille coupling reaction. Both monomer and polymer were analyzed by NMR, MS, FT-IR, UV, polarimetry, DSC-TGA, CD, fluorescent spectroscopy and GPC. The major difference between monomer and polymer is that a long wavelength Cotton Effect was observed for the polymer due to its more extended conjugation in the repeating unit and a highly rigid backbone in the polymer chain. Polymer has strong blue fluorescence due to the efficient energy migration from the extended n-electronic structure of the repeating unit of the polymer to the chiral binaphthyl core and is expected to have potential application in the materials of fluorescent sensors and chiral chromatographic packing for resolution of racemic amino acid.     

New diphosphite ligands for enantioselective asymmetric hydroformylation

A series of new diphosphite ligands have been easily prepared from BINOL derivatives; moderate enantioselectivities (up to 80% ee) and excellent regioselectivities (b/l up to 98/2) have been achieved in the Rh-catalyzed asymmetric hydroformylation of vinyl acetate.     

Prediction of paper permanence by accelerated aging II. Comparison of the predictions with natural aging results

Accelerated aging tests are credible and useful to predict paper permanence only if such tests can be shown to correlate with natural aging. In the first part of this study, a kinetic model was developed based on the accelerated aging results. In this report, we have shown that this kinetic model can indeed predict the natural aging results of lignin-free sheets with a statistical confidence. This is the first quantitative comparison of accelerated aging with natural aging.