NHC-Catalyzed Dual Stetter Reaction: A Mild Cascade Annulation for the Syntheses of Naphthoquinones, Isoflavanones, and Sugar-Based Chiral Analogues
作者:Rajendra N. Mitra、Krishanu Show、Debabrata Barman、Satinath Sarkar、Dilip K. Maiti
DOI:10.1021/acs.joc.8b01503
日期:2019.1.4
successfully employed for the construction of opticallypure sugar-based naphthoquinones and dihydroisoflavanones. Herein, NHC is found as a unique and powerful organocatalyst to construct homoatomic C–C cross-coupling, heteroatomic O–C bond formation, and cascade cyclization utilizing NO2 as a leaving group at ambient temperature. A mechanistic pathway of the new metal-free catalysis is predicted on
Comprehensive evaluation of antioxidant effects of Japanese Kampo medicines led to identification of Tsudosan formulation as a potent antioxidant agent
Insurance Drug List, using in vitro radical scavenging assays, including the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity assay, the superoxide anion scavenging activity assay, and the oxygen radical absorption capacity assay. Three of the formulations tested, namely, Tsudosan, Daisaikoto, and Masiningan, showed the most potent in vitro antioxidant activities and were selected for further
Synthesis of 3-Substituted 2-Aminonaphtho[2,3-<i>b</i>]furan-4,9-diones from 2-Hydroxy-1,4-Naphthoquinone and Nitroalkenes
作者:Manoj R. Zanwar、Veerababurao Kavala、Sachin D. Gawande、Chun-Wei Kuo、Ting-Shen Kuo、Mei-Ling Chen、Chiu-Hui He、Ching-Fa Yao
DOI:10.1002/ejoc.201300996
日期:2013.12
The efficient base-catalyzed synthesis of 3-substituted2-aminonaphtho[2,3-b]furan-4,9-dione derivatives from readily available precursors such as 2-hydroxy-1,4-naphthoquinone and nitroalkenes under aqueous conditions is described. Interesting features of this methodology are the conversion of a nitro functionality into an amino functionality in the absence of a reducing agent and the development of
Geometrically Selective Denitrative Trifluoromethylthiolation of β-Nitrostyrenes with AgSCF<sub>3</sub> for (<i>E</i>)-Vinyl Trifluoromethyl Thioethers
作者:Changge Zheng、Shuai Huang、Yang Liu、Chao Jiang、Wei Zhang、Ge Fang、Jianquan Hong
DOI:10.1021/acs.orglett.0c01714
日期:2020.6.19
An efficient copper(II)-promoted denitrative trifluoromethylthiolation under mild reaction conditions has been developed for vinyl trifluoromethyl thioethers to construct Cvinyl–SCF3 bonds with stable AgSCF3 as a source of the trifluoromethylthio. This reaction system tolerates a broad range of functional groups to commendably achieve a high product yield and excellent stereoselectivity of E/Z.
What Controls Regiochemistry in 1,3-Dipolar Cycloadditions of Münchnones with Nitrostyrenes?
作者:Justin M. Lopchuk、Russell P. Hughes、Gordon W. Gribble
DOI:10.1021/ol402385v
日期:2013.10.18
The distinct experimentally observed regiochemistries of the reactions between mesoionic münchnones and β-nitrostyrenes or phenylacetylene are shown by DFT/BDA/ETS-NOCV analyses of the transition states to be dominated by steric and reactant reorganization factors, rather than the orbital overlap considerations predicted by Frontier Molecular Orbital (FMO) Theory.