A fluorine scan of the phenylamidinium needle of tricyclic thrombin inhibitors: effects of fluorine substitution on pKaand binding affinity and evidence for intermolecular C–F⋯CN interactions
摘要:
三环凝血酶抑制剂的苯基氨定针中的氢原子与酶选择性口袋 S1 底部的 Asp189 发生相互作用,系统地将这些氢原子替换为氟原子,试图通过降低 pKa 值来改善药代动力学特性。F-替代后,pKa 值以及对凝血酶和胰蛋白酶的抑制常数 Ki 均有所降低。有趣的是,线性自由能关系(LFERs)显示,与胰蛋白酶相比,pKa 值的降低对凝血酶的结合亲和力影响更大。在苯基氨定针的 F-替代对抑制剂三环骨架中的三级胺中心 pKa 值的影响上观察到了意外现象,随后通过 X 射线晶体学分析和从头计算进行了合理化。通过对小分子 X 射线晶体结构的分析和剑桥结构数据库(CSD)的研究,获得了强方向性分子间 C–F⋯CN 交互作用的证据。
An unexpected formation of the novel 7-oxa-2-azabicyclo[2.2.1]hept-5-ene skeleton during the reaction of furfurylamine with maleimides and their bioprospection using a zebrafish embryo model
maleimides with secondary amines and NXS (X = Cl, Br, I) was developed, in which the N–X bonds generated in situ were used as difunctionalized reagents. The distinctive features of this multicomponent reaction include a simple green catalytic system, a spectral substrate range, and the late-stage modification of drug molecules. Most importantly, this umpolung radical cascade strategy exploits the in situ
A versatile and site-selective rhodium(III)-catalyzed aerobic oxidativealkenylation of arylacetamides including primary, secondary, and tertiary amides having a weak O-coordinating acetamide directing group with alkenes is described. In the reaction, air was utilized as a sole oxidant. The reaction was compatible with activated alkenes and maleimides.
The first example of copper-catalyzed four-component coupling reaction of aryl iodides, Se powder, secondary amines, and maleimides is developed. This reaction provides an efficient and concise route to access aminoarylselenated maleimides via double C–Se bonds and C–N bond formation. The appealing features of this transformation are the use of Se powder as a selenating reagent, a green catalytic system
Magnetic nanoparticles supported cinchona alkaloids for asymmetric Michael addition reaction of 1,3-dicarbonyls and maleimides
作者:Shi-Xuan Cao、Jia-Xi Wang、Zheng-Jie He
DOI:10.1016/j.cclet.2017.06.022
日期:2018.1
Abstract Magnetic nanoparticles Fe3O4@SiO2 supported cinchonaalkaloids (quinine and quinidine) were successfully synthesized as magnetically recoverable organocatalysts and characterized by FT-IR, XPS, SEM measurements, and elemental analysis. Their catalytic activity and stereoselectivity were preliminarily evaluated in the asymmetric Michael addition reaction of 1,3-dicarbonyls and maleimides. The
the first example of copper-catalyzed oxidative thioamination of maleimides with secondary amines and Bunte salts with the achievement of C-N and C-S bonds in a single flask. The protocol showcases a prominently broad substrate scope and is also efficient for the late-stage modification of an array of pharmaceuticals. Preliminary mechanistic investigation indicates copper-catalyzed oxidative amination