A highly efficient iridium-catalyzedhydrogenation of alpha,beta-unsaturated carboxylic acids has been developed by using chiral spiro-phosphino-oxazoline ligands, affording alpha-substituted chiral carboxylic acids in exceptionally high enantioselectivities and reactivities.
suggested that the mechanism of action may be that it interfered the formation of active dimeric iNOS but not affected transcription and translation. Furthermore, its good performance of anti-inflammatory effect on LPS-induced multiple inflammatory cytokines production, carrageenan-induced paw edema, and endotoxin-induced septic mice, was observed. We believe that these findings would provide an idea for the
炎症作为宿主对刺激的过度免疫反应,参与了许多疾病的发展。为了发现新的抗炎剂,并基于我们之前对海洋天然产物菊酰胺 B 的合成工作,合成了它和一系列衍生物,并评估了它们对抑制 LPS 诱导的 NO 产生的抗炎活性。然后进行初步的构效关系。其中,Chrysamide B 是最有效的抗炎剂,具有低细胞毒性和强烈抑制 NO 产生(IC 50 = 0.010 μM)和 iNOS 活性(IC 50 = 0.082 μM) 在 LPS 刺激的 RAW 264.7 细胞中。初步研究表明,其作用机制可能是干扰了活性二聚体 iNOS 的形成,但不影响转录和翻译。此外,观察到其对 LPS 诱导的多种炎性细胞因子产生、角叉菜胶诱导的爪水肿和内毒素诱导的败血症小鼠具有良好的抗炎作用。我们相信这些发现将为未来这些类似物的进一步修饰和研究提供思路。
FR2267764
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作者:D. Hamer、W. R. Magee、Sherril D. Christian、Harold E. Affsprung、Chii Lin、A. D. Tait、R. Long、G. H. Whitfield、M. Elliott、D. H. R. Barton、B. J. Garner、R. H. Wightman、D. E. A. Rivett、J. P. Dickinson、John Harley-Mason、J. H. New
DOI:10.1039/jr9640001847
日期:——
Cobalt-Catalyzed Asymmetric Hydrogenation of α,β-Unsaturated Carboxylic Acids by Homolytic H<sub>2</sub> Cleavage
作者:Hongyu Zhong、Michael Shevlin、Paul J. Chirik
DOI:10.1021/jacs.9b13876
日期:2020.3.18
The asymmetrichydrogenation of α, β-unsaturatedcarboxylicacids using readily prepared bis(phosphine) cobalt(0) 1,5-cyclooctadiene precatalysts is described. Di-, tri- and tetra-substituted acrylic acid derivatives with various substitution patterns as well as dehydro-α-amino acid derivatives were hydrogenated with high yields and enantioselectivities, affording chiral carboxylicacids including