Synthesis and organogelating ability of bis-urea pseudopeptidic compounds
摘要:
A large family of amphiphilic pseudopeptidic derivatives in which the aliphatic tails are connected to the pseudopeptidic moiety through urea functionalities have been prepared with excellent yields. The synthetic procedure is simple and very efficient and allows a modular variation of a large number of structural parameters. The self-assembling properties of the resulting compounds has been studied under different conditions and using different media. Very interestingly, many of the compounds obtained have revealed to act as very efficient organogelators at low concentrations. The resulting gels provide some unusual properties. Of particular relevance are the broad scope of organic solvents that can be gelated and the high thermal stability of the resulting gels. Gels that are stable up to temperatures close to 100 degrees C can be obtained in some instances. (C) 2013 Elsevier Ltd. All rights reserved.
C 2的大环化反应包含中心吡啶衍生间隔基的对称对称假肽会受到不同阴离子的影响。适当阴离子的选择为制备相应的大环结构提供了极好的结果。动力学研究表明,那些阴离子的存在既提高了产率,又提高了反应速度。在B3LYP / 6-31G *水平上的计算研究使我们能够合理化实验结果。所获得的过渡态(TSs)表明,阴离子与开链假肽链之间的相互作用具有稳定作用。阴离子使涉及的两个TS稳定化:第一个涉及两个亚基之间的初始键的形成并导致开链中间体,第二个涉及环状结构的形成。−当中心间隔基衍生自2,6-双(氨基甲基)吡啶时,能够充当模板,因为它通过与两个开环形成氢键来迫使开链中间体的两端彼此接近存在于中间体中的氨基酸亚基。与第一个TS相比,这使第二个TS的稳定程度更高,因此比起竞争性的低聚反应,它更有利于大环化。计算结果还使我们能够预测新实验的结果。因此,在先前使用的优化条件下,源自2,6-二氨基吡啶的假肽大环化
Macrocycle Synthesis by Chloride-Templated Amide Bond Formation
作者:Vicente Martí-Centelles、M. Isabel Burguete、Santiago V. Luis
DOI:10.1021/acs.joc.5b02676
日期:2016.3.4
prepared involving an anion-templated amide bond formation reaction at the macrocyclization step. Chloride anion was found to be the most efficient template in the macrocyclization process, producing improved macrocyclization yields with regard to the nontemplated reaction. The data suggest a kinetic effect of the chloride template, providing an appropriate folded conformation of the open-chain precursor