Biphenyl derived Schiff-base vanadium(<scp>v</scp>) complexes with pendant OH-groups—structure, characterization and hydrogen peroxide mediated sulfide oxygenation
作者:Patrick Plitt、Hans Pritzkow、Roland Krämer
DOI:10.1039/b403600j
日期:——
compounds the vanadium(V) cores contain distorted tetragonal pyramidal geometry around the dioxo- and oxovanadium site at which the N2O- and NO2-donor ligands bind equatorially. Complexes 1 and 3 display intramolecular hydrogen bonding of the pendant hydroxyphenyl group to a coordinated oxygen trans to a nitrogen atom and therefore serve as suitable models for the native site of vanadium dependent haloperoxidases
三齿的一系列单核氧钒(V)配合物希夫碱HL 1 –HL 4和H 2 L 5 –H 2 L 8衍生自6-苯基水杨醛 和 6-(2-羟苯基)水杨醛 和四个不同 胺类是合成的。系统选择配体 含有脂肪族或芳香族 氮,或烷氧基和苯氧基作为第三个供体原子。通过光谱方法在溶液和固态中对复合物进行表征。用VO 2 L 1 (1),VO 2 L 3 · 1 / 2EtOH(3),VO 2 L 4 (4),VO(O i Pr)L 7 · i PrOH(7)进行单晶X射线分析,VO(O i Pr)L 8 (8)和H 2 L 8。对于所有化合物,钒(V)的核在二氧羰基和氧钒基位点(N 2 O-和NO 2-施主)周围包含扭曲的四角锥几何形状配体赤道绑定。配合物1和3的侧链羟苯基的显示分子内氢键,以协调的氧反式给氮原子因此可以作为钒依赖性卤代过氧化物酶天然位点的合适模型。温度可变1 H NMR谱 揭示了在 乙腈解决方案。原地准备催化剂
Spectroscopic studies of Schiff bases of 2,2′-dihydroxybiphenyl-3-carbaldehyde and para substituted anilines
Abstract Five Schiffbases derivatives of 2,2′-dihydroxybiphenyl-3-carboxaldehyde and various para substituted anilines have been synthesised and studied by FT-IR, 1 H, 13 C, 15 N NMR and CPMAS spectroscopy. The structure of the Schiff base includes two intramolecular OH⋯O and OH⋯N hydrogen bonds forming a hydrogen-bonded chain. All Schiffbases studied exist in imine form in chloroform and acetonitrile
Catalysis of the Michael Addition Reaction by Late Transition Metal Complexes of BINOL-Derived Salens
作者:Venkatachalam Annamalai、Erin F. DiMauro、Patrick J. Carroll、Marisa C. Kozlowski
DOI:10.1021/jo025993t
日期:2003.3.1
basic sites. These unique complexes have been shown to catalyze the Michael reaction of dibenzyl malonate and cyclohexenone with good selectivity (up to 90% ee) and moderate yield (up to 79% yield). These catalysts are also effective in the Michael reaction between other enones and malonates. Kinetic data show that the reaction is first order in the Ni*Cs-BINOL-salen catalyst. Further experiments probed
to the hydroxyl group by a short hydrogen bond [molecule A: N⋯O=2.614(3), O⋯O=2.520(3) A; molecule B: N⋯O=2.594(4), O⋯O=2.526(3) A]. The OH⋯O −⋯ H + N bifurcated intramolecular hydrogen bonds are crystallographically asymmetric. The results of the FT-IR, 1H, 13C, 15NNMR and CPMAS study of the crystals are in agreement with the X-raydata. Instead of a continuous absorption, only a broad band is found
摘要 使用 X 射线衍射、FT-IR 和 CPMAS 光谱检查了 2,2'-二羟基联苯-3-甲醛与正丁胺的 Schiff 碱衍生物的晶体。它们的空间群是 P-1,a=8.377(2), b=12.214(2), c=14.774(3) A , α=76.62(3)°, β=81.34(3)°, γ=86.62( 3)°且Z=4。晶胞包含两个与对称性无关的两性离子。席夫碱质子化 N 原子的氢原子与 2 位羰基的氧原子相连,后者又通过短氢键与羟基相连 [分子 A:N⋯O=2.614( 3), O⋯O=2.520(3) A; 分子 B: N⋯O=2.594(4), O⋯O=2.526(3) A]。OH⋯O -⋯ H + N 分叉的分子内氢键在晶体学上是不对称的。晶体的 FT-IR、 1 H、 13 C、 15 N NMR 和 CPMAS 研究的结果与 X 射线数据一致。而不是连续吸收,只发现一个
Factor VIIa inhibitors: A prodrug strategy to improve oral bioavailability
作者:Jennifer R. Riggs、Aleksandr Kolesnikov、John Hendrix、Wendy B. Young、William D. Shrader、Dange Vijaykumar、Robin Stephens、Liang Liu、Lin Pan、Joyce Mordenti、Michael J. Green、Juthamas Sukbuntherng
DOI:10.1016/j.bmcl.2006.01.039
日期:2006.4
We have developed a series of potent and selective factor VIIa inhibitors based on the 2-[5-(5-carbamimidoyl-1H-benzoimidazol-2-yl)-6-hydroxy-biphenyl-3-yl]-succinic acid scaffold. These amidine-containing compounds have low oral bioavailability. Herein, we describe our efforts to improve the oral bioavailability of the parent amidine via a prodrug strategy where the amidine basicity and polarity were reduced with either an alkoxy-amidine or a carbamate prodrug. (C) 2006 Elsevier Ltd. All rights reserved.