Stereoselective Olefination of N-Sulfonyl Imines with Stabilized Phosphonium Ylides for the Synthesis of Electron-Deficient Alkenes
作者:Fan Fang、Yuan Li、Shi-Kai Tian
DOI:10.1002/ejoc.201001379
日期:2011.2
alkenes in moderate to excellent yields from readily accessible N-sulfonyl imines and stabilized phosphoniumylides. Significantly, the olefination reaction of N-sulfonylimines with nitrile-stabilized phosphoniumylides affords an array of α,β-unsaturated nitriles with high Z selectivity, and the reactions with ester-, amide-, and ketone-stabilized phosphoniumylides afford α,β-unsaturated esters, amides
已经开发了一种前所未有的方案,用于从易于获得的 N-磺酰基亚胺和稳定的鏻叶立德以中等至优异的产率立体选择性合成结构多样的缺电子烯烃。值得注意的是,N-磺酰亚胺与腈稳定的鏻叶立德的烯化反应提供了一系列具有高 Z 选择性的 α,β-不饱和腈,并且与酯、酰胺和酮稳定的鏻叶立德的反应提供了 α,β -分别具有高 E 选择性的不饱和酯、酰胺和酮。反应混合物的光谱分析和中间体的捕获允许提出合理的机制。初始亚胺/叶立德加成导致形成环化形成 1 的甜菜碱,2-氮杂膦烷随后消除亚氨基膦以产生烯烃。对于缺电子的 1,2-二取代烯烃的合成,甜菜碱中吸电子基团的存在允许通过质子转移在其两种非对映异构体之间快速相互转化。烯烃合成的 Z/E 选择性由两种甜菜碱非对映异构体形成相应的 1,2-氮杂膦非对映异构体的不同速率决定。相比之下,合成缺电子三取代烯烃的 Z/E 选择性源于稳定的鏻叶立德与 N-磺酰基亚胺的非对映选
Identification and optimization of piperine analogues as neuroprotective agents for the treatment of Parkinson’s disease via the activation of Nrf2/keap1 pathway
Parkinson's disease (PD) is a slowly progressive and complex neurodegenerative disorder. Up to date, there are no approved drugs that could slow or reverse the neurodegenerative process of PD. Here, we reported the synthesis of series of piperine analogues and the evaluation of their neuroprotective effects against hydrogen peroxide (H2O2) induced damage in the neuron-like PC12 cells. Among these analogues, 3b exhibited the most potent protection effect and its underlying mechanism was further investigated. Further results indicated that the ROS scavenging and cytoprotection effect of 3b might be related to the Nrf2 activation and upregulation of related phase II antioxidant enzymes, such as HO-1 and NQO1. In in vivo study, oral administration (100 mg/kg) of 3b significantly attenuated PD-associated behavioral deficits in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD and protected tyrosine hydroxylase-immunopositive dopaminergic neurons. Our results provided evidence that 3b might be a promising candidate for Parkinson's disease treatment. (C) 2020 Elsevier Masson SAS. All rights reserved.
Utility of 3-(thiophen-2-yl)prop-2-enoyl isothiocyanate in heterocyclic synthesis
作者:Amira A El-Sayed、Saad R Atta-Allah、Magdy M Hemdan
DOI:10.1177/1747519819862176
日期:2019.9
Convenient syntheses of quinazoline, benzothiazole, thiadiazole, imidazole, and thiourea derivatives starting from 3-(thiophen-2-yl)prop-2-enoyl isothiocyanate are described. The structures of the synthesized compounds are confirmed from their microanalytical and spectral data. Some of the products are examined for their antibacterial activity against Gram-positive and Gram-negative bacteria and fungi