Mechanism-Inspired Design of Bifunctional Catalysts for the Alternating Ring-Opening Copolymerization of Epoxides and Cyclic Anhydrides
作者:Brooks A. Abel、Claire A. L. Lidston、Geoffrey W. Coates
DOI:10.1021/jacs.9b05570
日期:2019.8.14
bifunctional complex in which the salen catalyst and an aminocyclopropenium cocatalyst are covalently tethered. A modular ligand design circumvents the extended linear syntheses typical of bifunctional catalysts, enabling systematic variation to understand and enhance catalytic activity. The optimized bifunctional aluminumsalen catalyst maintains excellent activity for the ring-openingcopolymerization of epoxides
A series of 1-alkyl-4-dialkylaminopyridinium halides derived from 4-dimethylamino- and 4-morpholinopyridines were synthesized and tested as phase-transfer catalysts in three typical reactions of dichlorocarbene: dehydration of benzamide, N-formylation of diphenylamine, and dichlorocyclopropanation of styrene. The catalytic performance of the above compounds was found comparable or higher than that
the volume of ions, NBO charges, and the interactions of anions and cations were calculated by Gaussian03 to explain the obtained density results. The second-order polynomial equation was adopted to correlate the relationship of density and temperature. Then, an isobaric thermal expansion coefficient, molecularvolume, and lattice potential energy were obtained from the density data. Viscosity was
AbstractA clean procedure for the synthesis of tetrahydrobenzo[c]xanthenes was established in the presence of a functional ionicliquid, 1-butyl-(4-dimethylamino)pyridinium hydroxide [BDMAP][OH]. The reaction was carried out via the one-pot multi-component condensation of aromatic aldehydes, cyclic 1,3-dicarbonyl compounds, and α-naphthol in aqueousmedia, to afford good to excellent yields ranging
摘要在功能性离子液体1-丁基-(4-二甲基氨基)吡啶鎓氢氧化物[BDMAP] [OH]存在下,建立了合成四氢苯并[ c ]黄嘌呤的清洁方法。该反应是通过在水性介质中一锅法将芳族醛,环状1,3-二羰基化合物和α-萘酚进行多组分缩合来实现的,在60-90范围内,产率从80%到85%不等。分钟 反应后,催化剂可以循环使用几次,而催化活性没有明显降低。 图形概要
Cancer-specific cytotoxicity of pyridinium-based ionic liquids by regulating hypoxia-inducible factor-1α-centric cancer metabolism
reduced hypoxia-induced HIF-1α activation. It selectively inhibited the viability of the human colon cancer cell line HCT116, compared to that of the normal fibroblast cell line WI-38. These activities were enhanced by increasing the alkyl chain length in the pyridinium. Under hypoxic conditions, dimethylaminopyridinium reduced the accumulation of HIF-1α and its target genes without affecting the HIF1A
由于其独特的性质和生物活性,离子液体 (IL) 引起了制药和医学领域的研究兴趣。缺氧诱导因子 (HIF)− 1α 是一种有吸引力的抗癌药物靶点,参与缺氧肿瘤微环境中的恶性肿瘤。在此,我们报告了 ILs 对 HIF-1α 通路的抑制活性及其作用机制。在吡啶鎓上取代二甲基氨基可减少缺氧诱导的 HIF-1α 激活。与正常成纤维细胞系 WI-38 相比,它选择性地抑制人结肠癌细胞系 HCT116 的活力。通过增加吡啶中的烷基链长度来增强这些活性。在低氧条件下,二甲基氨基吡啶减少了 HIF-1α 及其靶基因的积累,而不影响癌细胞中的HIF1A mRNA 水平。它通过直接抑制电子传递链复合物 I 来抑制耗氧率和 ATP 的产生,从而导致缺氧条件下细胞内氧含量增加和 HIF-1α 的氧依赖性降解。这些结果表明二甲基氨基吡啶抑制缺氧癌细胞中的线粒体和 HIF-1α 依赖性葡萄糖代谢途径。这项研究通过调节癌症代谢提供了对基于吡啶离子的