N1,N10-Ethylene-bridged high-potential flavins: synthesis, characterization, and reactivity
摘要:
N-1,N-10-Ethyleneisoalloxazinium chloride and its 8-Cl-, 7-CF3-, and 3-CH3-7-CF3-substituted analogs were synthesized for the purpose of exhibiting thermal reactivity with organic substrates. The new flavins were characterized spectroscopically and electrochemically, and were found to react with amines, thiols, and phenylhydrazine, the latter case exhibiting catalytic aerobic recycling. Reactions of aliphatic benzylic and cyclopropyl amines with the 7-CF3 analog were also compared to their oxidations by tris(phenanthroline)iron(III). All reactions of the flavinium salts appear to occur through heterolytic rather than homolytic mechanisms. (C) 2001 Elsevier Science Ltd. All rights reserved.
Neocuproine–KOtBu promoted intramolecular cross coupling to approach fused rings
作者:Chang-Liang Sun、Yi-Fan Gu、Wei-Ping Huang、Zhang-Jie Shi
DOI:10.1039/c1cc13907j
日期:——
Polycycles can be produced with different linkages (A, B = O, N, C, S) by constructing biaryl CâC bonds vianeocuproineâKOtBu promoted cross coupling between CâXs and CâHs.
多环化合物可以通过构建联芳基C–C键,在二茂铜–KOtBu促进下,通过C–X和C–H之间的交叉偶联反应,利用不同的键合方式(A, B = O, N, C, S)来合成。
Isotope effects on hydride transfer between NAD+ analogs
作者:Drazen Ostovic、Roger M. G. Roberts、Maurice M. Kreevoy
DOI:10.1021/ja00364a026
日期:1983.12
Primary kinetic hydrogen isotope effects (KIE's) for hydride transfer between NAD/sup +/ analogues have been measured for reactions with equilibrium constants ranging from 0.7 to 10/sup 16/. There is no sign of the sharp change in KIE which would signal the change of a rate limiting step in a multistep mechanism, and other evidence also indicates a one-step mechanism. The secondary KIE produced by
对于平衡常数范围为 0.7 到 10/sup 16/ 的反应,已经测量了 NAD/sup +/ 类似物之间氢化物转移的主要动力学氢同位素效应 (KIE)。没有迹象表明 KIE 的急剧变化表明多步机制中速率限制步骤的变化,其他证据也表明了单步机制。当转移原子为 D 时,通过将受体位点上已连接的氢从 H 变为 D 产生的次级 KIE 比转移原子为 H 时小 10%。这些结果与初级 KIE 的值相结合,强烈表明某些反应坐标中的核隧穿。
Primary Kinetic Isotope Effects on Hydride Transfer from 1,3-Dimethyl-2-phenylbenzimidazoline to NAD<sup>+</sup> Analogues
作者:In-Sook Han Lee、Eun Hee Jeoung、Maurice M. Kreevoy
DOI:10.1021/ja004232+
日期:2001.8.1
around 1012. This is consistent with Marcus theory of atom transfer, assuming that there are no high-energy intermediates. Within this theory, the perpendicular effect is responsible for most of the change in KIE. The Marcus theory of atom transfer is consistent with a linear, triatomic model of the reaction. Perpendicular effects arise from the systematic decrease of bond distances and increase of bond