Evaluation and Development of Practical Routes to an Enantiomerically Pure <i>C</i><sub>2</sub>-Symmetric Diamine Building Block
作者:Staffan Karlsson、Jan Lindberg、Henrik Sörensen
DOI:10.1021/op400292m
日期:2013.12.20
Several routes to an enantiomericallypure C2-symmetric diamine were evaluated and modified to scalable methods. A Zn/Me3SiCl-mediated reductive coupling of an imine was found to be superior to the other methods investigated, allowing us to safely prepare the enantiomericallypure diamine also on a large scale. One key step in this method was a highly efficient resolution of a stereoisomeric mixture
评价了对映体纯的C 2对称二胺的几种途径,并将其改进为可扩展的方法。发现Zn / Me 3 SiCl介导的亚胺还原偶联优于其他研究方法,这使我们也可以大规模安全地制备对映体纯的二胺。该方法的一个关键步骤是通过与(-)-二苯甲酰基-1-酒石酸形成盐来高效拆分二胺的立体异构混合物。获得的对映体纯的C 2对称二胺进一步用作合成有效Kv1.5通道阻滞剂的关键组成部分。
Antioxidant activity of α-pyridoin and its derivatives: possible mechanism
α-pyridoin and its 5,5′- or 6,6′-bis-substituted derivatives (2–7) and compared their capacities to scavenge galvinoxyl radical (GO˙) and protect human red blood cells (RBCs) from oxidative haemolysis. It was found that the compounds (5 and 6) with a methyl or methoxy group at the 5-position exhibit significantly higher GO˙-scavenging and anti-haemolysis activities than other derivatives and vitamin C
Deformative Transition of the Menschutkin Reaction and Helical Atropisomers in a Congested Polyheterocyclic System
作者:Yung-Yu Chang、Tse-Lok Ho、Wen-Sheng Chung
DOI:10.1021/jo501815y
日期:2014.11.7
and 9.62 × 10–6 s–1 mol–1 L, respectively; thus, the formation rate of (P/M)-2A is one of the slowest rates ever reported for a Menschutkinreaction. The N-methyl protons in (P/M)-2A exhibit a significant upfield shift (Δδ 1.0 ppm) in its 1H NMR, compared to those without a nearby phenyl, indicating a strong CH-π interaction is involved. Conformational flexibility in dipyridylethene 9 is clearly shown
以六步顺序合成了设计用于探测门舒特金反应极限的4,7-菲咯啉多环1A。根据VT-NMR实验估计,rac - 2A中N-甲基附近的苯环的旋转势垒约为8.118.1 kcal / mol,使其成为新型的螺旋阻转异构体。发现MeI的9和1A的甲基化速率常数分别为2.22×10 –4和9.62×10 –6 s –1 mol –1L。因此,(P / M)-2A的形成速率是有报道的门舒特金反应最慢的速度之一。与没有附近苯基的质子相比,(P / M)-2A中的N-甲基质子在1 H NMR中显示出显着的高场位移(Δδ1.0 ppm)。二吡啶基乙烯9与BH 3的络合形成螺旋阻转异构体(P,P / M,M)-10清楚地显示出构象柔韧性。1A和9的共轭酸的p K a值测定乙腈中的乙酰胆碱的含量分别为4.65和5.07,与吡啶14a的相比小得多(p K a = 12.33),这意味着1A和9的碱度,亲核性和胺烷基