Peptide conformational distributions as studied by electron-transfer kinetics
摘要:
The preparation and electron-transfer (ET) behavior of a homologous series of alanine oligomers bearing naphthoyl groups at the N-termini and biphenylylamide groups at the C-termini is described. Electron pulse radiolysis was used to generate the corresponding radical anions, and the rates of ET were monitored at 700 nm (decay of donor) and at 500 nm (growth of acceptor). Several systems displayed ET decays too fast to measure (k(et) > 10(10)), and in the others multiexponential decay kinetics were observed. The ET decay of dipeptide 3 could be fit to two exponential described by rate constants of 5.2 x 10(8) (22%) and 5.6 x 10(9) s-1 (78%). In the longer peptides, the fit of the rate constants (and their relative contributions to total intensity) becomes less well-defined, suggesting additional conformational diversity.
描述了作为活化氨基酸衍生物的氮杂内酯的第一次催化不对称共轭加成反应向烯酮的发展和进一步发展。第一代方法是从孤立的氮杂内酯开始的,而第二代方法中的氮杂内酯可以从外消旋的N开始原位生成。苯甲酰化氨基酸。第三个进化阶段可以利用外消旋未保护的α-氨基酸直接形成高度对映体富集和非对映体纯的带掩蔽季铵氨基酸产物,并带有一个附加的叔立体中心。通过使用稳固的平面手性bis-Pd催化剂,布朗斯台德酸(HOAc或BzOH; Ac =乙酰基,Bz =苯甲酰基)和布朗斯台德碱(NaOAc),通过协同活化来实现逐步经济转型。特别是第二代和第三代方法提供了快速而多样化的途径,可从廉价的散装化学品中获得生物学上令人感兴趣的非天然季氨基酸衍生物。这样,可以以非对映体纯形式制备高度对映体富集的无环α-氨基酸,α-烷基脯氨酸和α-烷基焦谷氨酸衍生物。此外,
Direct Resolution of Optically Active Isomers on Chiral Packings Containing Ergoline Skeletons. 5. Enantioseparation of Amino Acid Derivatives
作者:A. Messina、A. M. Girelli、M. Flieger、M. Sinibaldi、P. Sedmera、L. Cvak
DOI:10.1021/ac950698c
日期:1996.4.1
alkaloid-based chiral stationary phase preparation is described. Synthesis is based on bonding the allyl derivative of terguride to mercaptopropylsilanized silica gel. The packing exhibits higher content of chiral selector, stability, reproducibility, and enantioselectivity toward amino acids compared to that previously studied. The chromatographic behavior of amino acids with different side chains and substituent
[EN] ARYLAMIDES AND METHODS OF USE THEREOF<br/>[FR] ARYLAMIDES ET LEURS PROCÉDÉS D'UTILISATION
申请人:GENZYME CORP
公开号:WO2021113806A1
公开(公告)日:2021-06-10
The present disclosure relates to heterocyclic compounds, pharmaceutically acceptable salts thereof, and pharmaceutical preparations thereof. Also described herein are compositions and the use of such compounds in methods of treating diseases and conditions mediated by deficient CFTR activity, in particular cystic fibrosis.