Ring−Chain Interconversion in High-Performance Polymer Systems. 3. Cyclodepolymerization of Poly(<i>m</i>-phenylene isophthalamide) (Nomex) and Entropically Driven Ring-Opening Polymerization of the Macrocyclic Oligomers so Produced
作者:Abderrazak Ben-Haida、Philip Hodge、Howard M. Colquhoun
DOI:10.1021/ma0401370
日期:2005.2.1
of benzanilide at 150 °C for 70 h. Treatment of a concentrated solution of the macrocyclic oligomers (25% w/v) with 4 mol % of sodium hydride or the sodium salt of benzanilide in a solution of lithium chloride in dimethyl sulfoxide at 170 °C for 6 h resulted in efficient entropicallydriven ring-opening polymerizations to give poly(m-phenylene isophthalamide), characterized by infrared and 1H NMR spectroscopies
同源系列大环低聚酰胺的已经以高收率制备了的间苯二甲酰氯反应以米伪高稀释条件下苯二胺。产品的特征在于红外光谱和1 H NMR光谱,基质辅助激光解吸电离飞行时间质谱和凝胶渗透色谱(GPC)。制备了一系列线性低聚物用于比较。大环的大小从环状三聚体直至至少环状九聚体(90个环原子)不等。通过聚(m)的环解聚,高收率制备了相同的同源系列大环寡聚物。-亚苯基间苯二甲酰胺)(Nomex)。通过在150°C下用3-4 mol%的氢化钠或苯甲酰苯胺的钠盐处理聚合物在含氯化钙或氯化锂的二甲亚砜中的1%w / v溶液,可以最佳地实现环化聚合。在170°C下用4 mol%的氢化钠或苯甲酰苯胺的钠盐在氯化锂的二甲亚砜溶液中处理大环低聚物(25%w / v)的浓溶液6小时,可得到有效的熵驱动开环聚合,得到聚(米由红外和亚苯基间苯二甲酰胺),其特征在于1 1 H NMR波谱,并通过GPC。所获得的分子量与市售聚合物的分子量相当。
Anion-directed assembly: the first fluoride-directed double helix
作者:Simon J. Coles、Jeremy G. Frey、Philip A. Gale、Michael B. Hursthouse、Mark E. Light、Korakot Navakhun、Gemma L. Thomas
DOI:10.1039/b210847j
日期:2003.2.20
The crystal structures of anion complexes of two nitro-aromatic functionalised isophthalamides are reported; the structures reveal assembly around anions in the solid-state and in the case of the fluoride complex of receptor 2, the formation of a double helix.
Hepatitis C Virus (HCV) infects 200 million individuals worldwide. Although several FDA approved drugs targeting the HCV serine protease and polymerase have shown promising results, there is a need for better drugs that are effective in treating a broader range of HCV genotypes and subtypes without being used in combination with interferon and/or ribavirin. Recently, the crystal structure of the core of the HCV E2 protein (E2c) has been determined, providing structural information that can now be used to target the E2 protein and develop drugs that disrupt the early stages of HCV infection by blocking E2's interaction with different host factors. By targeting sites containing conserved E2 amino acids in the CD81 binding site on HCV E2, one might also be able to develop drugs that block HCV infection in a genotype-independent manner. Using the E2c structure as a template, a structural model of the E2 protein core (residues 421-645) was developed that includes the three amino acid segments that are not present in the E2c crystal structure. Blind docking of a diverse library of 1715 small molecules to this model led to the identification of a set of 34 ligands predicted to bind near conserved amino acid residues involved in the HCV E2:CD81 interaction. Surface plasmon resonance was used to screen the ligand set for binding to recombinant E2 protein, and the best binders were subsequently tested to identify compounds that inhibit the infection of hepatocytes by HCV. One compound, 281816, blocked E2 binding to CD81 and inhibited hepatocyte infection by HCV genotypes 1a, 1b, 2a, 2b, 4a and 6a with IC50's ranging from 2.2 μM to 4.6 μM. Methods are described for preventing or treating HCV infection using small molecule inhibitors such as 281816 that target E2 and disrupt its interactions.
Synthesis and Biological Evaluation of Distamycin Analogues - New Potential Anticancer Agents
Eight of analogues of distamycin, potential minor‐groove binders, were synthesized and tested for in‐vitro cytotoxicity towards human breast cancer cells MCF‐7 and MDA‐MB‐231. The method of synthesis is simple and convenient. All of the compounds 1–8 showed antiproliferative and cytotoxic effects against both cell lines in the range 3.47 to 12.53 μM for MDA‐MB‐231 and 4.35 to 12.66 μM for MCF‐7. All