Rate and equilibrium studies of the reaction of oxyanions with 2-phenyloxazol-5(4H)-one
作者:Edwin Chrystiuk、Adelina Jusoh、Dino Santafianos、Andrew Williams
DOI:10.1039/p29860000163
日期:——
Equilibrium constants for the reaction of phenoxide ions with 2-phenyloxazol-5(4H)-one at 25 °C and 1 M ionic strength obey a Brønsted relationship (log kOH/kArO= log K′=–1.73pKArOH– 15.81) and are not subject to steric effects from ortho-substituents. Both forward and reverse rate parameters exhibit steric effects, and the Brønsted equations for meta- and para-substituted species are log kOH=–0.81
在25°C和1 M离子强度下,酚盐离子与2-苯基恶唑-5(4 H)-one反应的平衡常数服从布朗斯台德关系(log k OH / k ArO = log K '= –1.73p K ArOH – 15.81),并且不受邻位取代基的空间位阻的影响。正向和反向速率参数均显示出空间效应,间位和对位取代物种的Brønsted方程为log k OH = –0.81 p K ArOH + 9.75,log k ArO = 0.95p KArOH – 6.40。在p K ArOH 5-11的区域内,Brønsted线没有中断,这与一个过渡态一致。低碱度的氧阴离子存在向上偏差(p K XOH <5);这些氧阴离子之一,甜菜碱,由于其与恶唑酮的反应大于2,具有溶剂性氘氧化同位素作用,这与攻击这些物质的一般基本机理相符。酚酸根阴离子的亲核攻击结果与羰基的协同位移一致。
Rate-controlling step of oxazolinone formation. Secondary and solvent kinetic isotope effects
作者:Michael S. Matta、Mark E. Andracki
DOI:10.1021/ja00307a034
日期:1985.10
Determination de l'effet isotopique cinetique secondaire du deuterium lors de la formation de la phenyl-2 oxazoline-2one-5 par hydrolyse basique de l'hippurate de nitro-4 phenyle
Determination de l'effet isotopique cinetique secondaire du deuterium lors de la形成 de la phenyl-2 oxazoline-2one-5 par hydrolyse basique de l'hippurate de nitro-4 phenyle
The mechanism of hydrolysis and ethylaminolysis of N-benzoylglycine and N-benzoylsarcosine esters
作者:Charles R. Farrar、Andrew Williams
DOI:10.1039/p29800000181
日期:——
The hydrolysis and ethylaminolysis of N-benzoylglycine and N-benzoylsarcosineesters have been studied for a range of leaving hydroxy-functions with pKa from 5.45 to 15.5. Ethylaminolysis of N-benzoylglycinate esters involves kinetic terms in [EtNH2] and [EtNH2][OH–]. The mechanism of ethylaminolysis of the glycinates does not involve the oxazolinone intermediate as a major contributor to the reaction
Synthesis and optimization of tri(propylene glycol) glycerolate diacrylate cross-linked polystyrene resin in polypeptide synthesis: role of the macromolecular support in solid phase peptide synthesis
作者:P. G. Sasikumar、K. S. Kumar、C. Arunan、V. N. Rajasekharan Pillai
DOI:10.1039/b206879f
日期:2002.12.19
cross-linked polystyrene support for solidphase peptide synthesis was prepared by aqueous radical suspension polymerization. The peptides were grown from the hydroxy functionality of the cross-linker in the polymer and this makes it unique among other styrene-based polymer supports that are currently used in polypeptide synthesis. The role of the polymer support in peptide synthesis was established by studies
通过水基自由基悬浮聚合反应制备了用于固相肽合成的新型三(丙二醇)甘油酸酯二丙烯酸酯交联聚苯乙烯载体。肽从聚合物中交联剂的羟基官能团生长而来,这使其在多肽合成中目前使用的其他基于苯乙烯的聚合物载体中独树一帜。通过描述固相合成中涉及的合成步骤的优化研究,确立了聚合物载体在肽合成中的作用。优化研究包括Ç端氨基酸掺入,Ñ α-Fmoc和Boc脱保护,酰化反应以及从支持物上去除目标肽。与Merrifield树脂相比,通过对酰胺键形成的反应性研究,研究了聚合物主链交联的性质和程度与连接的氨基的反应性之间的依赖性。通过合成β-淀粉样肽(1-42)的(34-42)片段的“困难”序列来研究新支持物的树脂状行为,并与市售的Merrifield和Sheppard树脂进行了比较。支持物的合成用途是通过合成23个残基的Ca 2+ NR 2B肽底物来建立的/钙调蛋白结合肽的产率高和纯度高。树脂珠粒的更好的溶剂化,肽合
Litvinenko, L. M.; Kosmynin, V. V.; Kaida, L. N., Journal of Organic Chemistry USSR (English Translation), 1986, vol. 22, # 4, p. 784 - 785
作者:Litvinenko, L. M.、Kosmynin, V. V.、Kaida, L. N.、Savelova, V. A.、Verbovaya, I. P.