Synthesis and Anti-HCV Activity of 4-Hydroxyamino α-Pyranone Carboxamide Analogues
摘要:
High genetic variability in hepatitis C virus (HCV), emergence of drug resistant viruses and side effects demand the requirement for development of new scaffolds to show an alternate mechanism. Herein, we report discovery of new scaffold I based on 4-hydroxyamino alpha-pyranone carboxamide as promising anti-HCV agents. A comprehensive structure activity relationship (SAR) was explored with several newly synthesized compounds. In all promising compounds (17-19, 21-22, 24-25, and 49) with EC50 ranging 0.15 to 0.40 mu M, the aryl group at C-6 position of alpha-pyranone were unsubstituted. In particular, 25 demonstrated potential anti-HCV activity with EC50 of 0.18 mu M in cell based HCV replicon system with lower cytotoxicity (CC50 > 20 mu M) and provided a new scaffold for anti-HCV drug development. Further investigations, including biochemical characterization, are yet to be performed to elucidate its possible mode of action.
Transition‐Metal‐Promoted Direct C−H Cyanoalkylation and Cyanoalkoxylation of Internal Alkenes
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Radical C−C Bond Cleavage of Cycloketone Oxime Esters
作者:Jiang Lou、Yuan He、Yunlong Li、Zhengkun Yu
DOI:10.1002/adsc.201900402
日期:2019.8.21
d alkyl‐Heck‐type cross‐coupling of olefinic C−Hbonds has been a challenge in the C−H activation area. Herein, we report FeCl3‐promoted efficient direct C−Hcyanoalkylation of internal alkenes, that is, ketene dithioacetals, with cycloketone oxime esters via radical C−C bond cleavage under the redox‐neutral conditions. With CuCl2 as the catalyst under a dioxygen atmosphere direct C−H cyanoalkoxylation
These precursors are easily accessible from aryl methyl ketones. Various functional groups like alkyl, aryl, nitrile, amine, aroyl and thiomethyl can be directly installed to the benzene ring. The one-pot approach for the construction of thiomethylated-benzene nucleus was also developed. The structure of the synthesized compound was confirmed by X-ray crystallography.
transition metal free, highly efficient, sulfenylation of ketene dithioacetals catalyzed by an HBr–DMSO system is achieved. This strategy employs inexpensive and readily available HBr and DMSO to provide a direct C–H bond sulfenylation with a broad range of aryl thiols. Highlights of the present strategy are convenient, straightforward approach, metal free, short reaction time and excellent yields. This
Efficient trifluoromethylation of C(sp<sup>2</sup>)–H functionalized α-oxoketene dithioacetals: a route to the regioselective synthesis of functionalized trifluoromethylated pyrazoles
作者:N. Sharma、N. Kumari、T. S. Chundawat、S. Kumar、S. Bhagat
DOI:10.1039/c7ra01130j
日期:——
An operationally simple approach for the regioselective construction of diversely substituted trifluoromethylated pyrazoles via nucleophilic trifluoromethylation of iodo-substituted α-oxoketene dithioacetals is described. X-ray crystallographic studies confirmed the trifluoromethylation as well as formation of a regioselective cyclized product. Furthermore, trifluoromethylated pyrazoles bearing thiomethyl
α-oxoketenedithioacetals 1a–l are subjected to fluorination using selectfluor 2 to yield the corresponding stable α-fluoro-α-oxoketenedithioacetals 3a–l in 61–75% overall yields. In Route 2 a four-componentone-pot protocol was followed involving addition of a mixture of active methylene ketone and carbon disulfide to sodium tert-butoxide suspended in tetrahydrofuran and dimethylformamide followed by