Umpolung Strategy for Synthesis of β-Ketonitriles through Hypervalent Iodine-Promoted Cyanation of Silyl Enol Ethers
摘要:
An efficient method to synthesize beta-ketonitriles from silyl enol ethers by an umploung hypervalent iodine(III)-CN species generated in situ from PhIO/BF3 center dot Et2O/TMSCN has been developed for the first time. This method can be applied to structurally diverse aromatic and aliphatic substrates and further extended to preparation of bioactive compounds like 5-aminopyrazole and 5-aminoisoxazole.
Reactions of 5-aminoisoxazoles with α,β-unsaturated ketones in t-butanol on heating afforded 4,7-dihydroisoxazolo [5,4-b]pyridines. However, when the reactions were carried out at 20° using ethylene glycol as the solvent, the kinetically controlled amino adducts were obtained in excellent yields. The amino adducts were converted into the thermodynamically controlled 4,7-dihydroisoxazolo[5,4-b]pyridines
Newly Designed Quinolinol Inhibitors Mitigate the Effects of Botulinum Neurotoxin A in Enzymatic, Cell-Based, and ex Vivo Assays
作者:Paul T. Bremer、Michael Adler、Cecilia H. Phung、Ajay K. Singh、Kim D. Janda
DOI:10.1021/acs.jmedchem.6b01393
日期:2017.1.12
potentially fatal condition, botulism. Herein, we investigated 8-hydroxyquinoline (quinolin-8-ol) as a potential inhibitor scaffold for preventing the deadly neurochemical effects of the toxin. Quinolinols are known chelators that can disrupt the BoNT/A metalloprotease zinc-containing active site, thus impeding its proteolysis of the endogenous protein substrate, synaptosomal-associated protein 25
肉毒杆菌神经毒素A(BoNT / A)是最致命的毒素之一,是潜在致命疾病肉毒杆菌中毒的病原体。在这里,我们研究了8-羟基喹啉(quinolin-8-ol)作为潜在的抑制支架,以防止毒素的致命神经化学作用。喹啉醇是已知的螯合剂,其可以破坏BoNT / A金属蛋白酶的含锌活性位点,从而阻碍其对内源性蛋白质底物突触体相关蛋白25(SNAP-25)的蛋白水解。利用这些信息,通过制备粗磺酰胺库并在BoNT / A LC酶法测定中评估该库,探索了喹啉5磺酰胺支架的结构-活性关系(SAR)。根据对接研究的结果,对磺胺类命中化合物的效能进行了优化,ķ我。这些喹啉醇类似物在基于细胞的SNAP-25裂解模型和BoNT / A介导的肌肉麻痹的离体测定中显示出抑制活性。
Hoveyda–Grubbs II Catalyst: A Useful Catalyst for One-Pot Visible-Light-Promoted Ring Contraction and Olefin Metathesis Reactions
A one-pot reaction to synthesize functionalized 2H-azirines through visible-light-mediated ring contraction and olefinmetathesis of isoxazoles is described. Hoveyda–Grubbs II catalyst was found to function as a photocatalyst for these transformations, allowing these processes to be carried out in a one-pot manner. This study offers a new entry for the application of Grubbs catalysts as efficient photocatalysts
chemoselective reaction between 5-aminoisoxazoles and α-diazocarbonyl compounds has been described. Both Wolff rearrangement and N–H insertion products can be obtained selectively by the judicious choice of reaction conditions. In the case of the Wolff rearrangementreactions, the N-isoxazole amides are accessed as the sole products under thermal conditions. On the other hand, α-amino acid derivatives
The study of reactions of α-chlorocinnamonitriles with hydroxylamine
作者:V. G. Nenajdenko、I. V. Golubinskii、O. N. Lenkova、A. V. Shastin、E. S. Balenkova
DOI:10.1007/s11172-006-0029-1
日期:2005.7
The E-isomers of α-chlorocinnamonitriles react with hydroxylamine to give a mixture of isomeric aminoisoxazoles, while the Z-isomers yield 3-aryl-2-chloroacrylamide oximes.
α-氯肉桂腈的E异构体与羟胺反应生成一 mixture of isomeric aminoisoxazoles,而Z异构体则产生3-芳基-2-氯丙烯酰胺肟。