Rhodium-catalyzed CH activation/cyclization of enaminones with sulfoxonium ylides toward polysubstituted naphthalenes

A rhodium-catalyzed ortho-CH functionalization and annulation between enaminones and sulfoxonium ylides was developed, affording a series of multi-substituted naphthalenes in good to moderate yields with excellent functional group compatibility. The procedure featured with enaminone acting as both a directing and cyclization bifunctional group, and the application of sulfoxonium ylide in CH functionalization.     

Analysis of Zoledronic Acid and Its Related Substances by Ion-Pair RP-LC

A simple high-performance liquid chromatographic method – ion-pair reversed- phase high performance liquid chromatography (RPIC) has been developed and employed for the analysis of zoledronic acid and its related substances in bulk material and commercial dosage forms. The mobile phase was a mixture of methanol (20%) and 5 mmol L^–1 phosphate buffer (80%) containing 6 mmol L^–1 tetrabutylammonium bromide, adjusted to pH 7.0 with sodium hydroxide. C₈ column was used as the stationary phase. The chromatographic conditions were optimized. The active ingredient – zoledronic acid was successfully separated from its related substances, including remained imidazol-1-yiacetic acid in the synthesis of zoledronic acid and other possible impurities of oxidation and decomposition. The excipients did not interfere with the determination of zoledronic acid in commercial dosage formulations. The method was rapid, simple, accurate and reproducible. It was not only successfully employed for the assay of zoledronic acid in bulk material and pharmaceutical dosage forms but also for the determination of its related substances.     

Synthesis and red luminescence of Pr-doped CaTiO3 nanophosphor from polymer precursor

Uniform and sphere-like nanoparticles of crystalline Pr³⁺-doped CaTiO₃ have been prepared from complex polymer precursor at 600°C, in which, metal atoms are previously dispersed by citric acid in ethylene glycol solvent. The decomposition process of the precursor, crystallization, and particle sizes of CaTiO₃ have been investigated by using thermal analysis, powder X-ray diffraction and transmission electron microscopy. Diffuse reflectance spectra, photoluminescence and decay curve indicate that a strong red emission located at the nearly NTCS “ideal red” site is deduced from the energy transfer from the band gap absorption to doping Pr³⁺ ions. The thermoluminescence curves exhibit that a potential long phosphorescent material based on Pr³⁺-doped CaTiO₃ will be explored in future.     

Physicochemical and structural properties of bacteriostatic sulfonamides: Theoretical study

A theoretical study at the Hartree–Fock and density functional theory levels is performed on sulfonamide‐type bacteriostatic compounds with the aim to provide an insight into their structure–activity relationship. The basicity of the p‐amino group is analyzed by means of the proton affinities and the protonation energies, showing that molecules presenting bacteriostatic activity are less basic, i.e., they are characterized by larger protonation energies and smaller proton affinities. The acidity of the amide group is analyzed through the deprotonation energy. The results reveal that the more acidic molecules present a larger bacteriostatic activity. This result is also confirmed from a study of bond orders. A bond order analysis of the amide group suggests that the electron attracting group in these molecules is responsible for the increase in acidity. The charge of the SO₂ group is also shown to be affected by the presence of the electron attracting group and consequently related to the acidity of the molecules. A geometric analysis shows that structures in which the amino group is more coplanar with respect to the benzenic ring possess larger bacteriostatic activity. A conformational analysis of these molecules illustrates that active molecules have relatively larger torsion energy barriers. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 94: 165–172, 2003     

聚丙烯微孔膜基渐变聚合物的制备,结构与性能的研究

以聚丙烯微孔膜为基材，通过扩散控制原位共聚合的方法在人填充了组成沿膜的厚度方向逐渐改变的无规共聚物，Ｘ－光电子能谱（ＸＰＳ）、全反射红外光谱（ＡＴＲ）以及动态粘弹谱的分析结果。说明所制备得到的合膜具有明显的渐变聚合物性质。     

The Intelligent Properties of Micro－reactors for Preparating Nanoparticles

TiO2 nanoparticles were synthesized by using micro-reactors. The shape and size of the nanoparticles produced from the original micro-reactors and the five times recycled micro-reactorsmother liquor were investigated on transmission electron microscopy (TEM) by using the original sample, freeze prepared sample, and dyeing treated sample, respectively. UV-VIS spectrometry was used to study the growth process of TiO2 nanoparticles in main reactors. The results showed that micro-reactors with nanometer magnitude had spherical or oval structures, and could restore to their original structure after they were destroyed. The products prepared in the original micro-reactors were similar to that in the micro-reactors recycled for many times, suggesting that the micro-reactors had memory function.     

混合高序铜法立体选择性合成（±）—EpilitsenolideC2

混合高序铜法立体选择性合成（±）┐ＥｐｉｌｉｔｓｅｎｏｌｉｄｅＣ２陈祖兴李焰＊黄精美黄锦霞徐章煌（湖北大学化学系武汉４３００６２）关键词烷叉基二氢羟基甲基（３Ｈ）呋喃酮，混合高序铜，立体选择性反应１９９６－０８－２８收稿，１９９７－０５－０６修回湖北...     

Self-assembled hybrid nanofibers confer a magnetorheological supramolecular hydrogel

Most magnetorheological materials, composed of magnetic microparticles in a liquid, require significant amounts of magnetic particles and a large magnetic field to achieve the desired effects. Here, we report on a new type of magnetorheological materials consisting of small amounts of magnetic nanoparticles (0.8 wt %) but exhibiting large rheological change (i.e., a gel-sol transition) upon the application of a small magnetic field. We use self-assembly to create hybrid nanofibers, which consist of supramolecular hydrogelators and magnetic nanoparticles, as the matrices of the hydrogel. Localized in the nanofibers at a distance of 1-2 nm, the magnetic nanoparticles occupy a small volume fraction of the hydrogel, significantly enhancing the magnetic dipole interactions between them, which results in the large magnetoresponse. This strategy generates a hierarchical nanostructure and eliminates several drawbacks of the simple mixture of polymers with nanoparticles, and thus provides a new methodology that uses magnetic force to control the nanostructures and properties of soft materials.     

Two Novel Alkaloids from Zanthoxylum nitidum

Two novel alkaloids, 4,5‐dihydroxy‐1‐methyl‐3‐oxo‐2‐(trichloromethyl)‐3H‐indolium chloride ( 1 ) and 4‐(2‐methoxyethyl)‐N,N‐dimethylbenzenamine ( 2 ), were isolated from the EtOH extract of the roots of Zanthoxylum nitidum. Their structures were identified on the basis of spectroscopic and mass‐spectrometric analyses.     

Coaxial electrospinning core-shell fibers for self-healing scratch on coatings

Polystyrene (PS) fibers with core-shell structure were prepared by coaxial electrostatic spinning using liquid epoxy or curing agent as the core and PS solution as the shell. Scratch self-healing coatings were realized by using the healant-loaded core-shell fibers in the matrix.