18-Crown-6 as a catalyst in the dialkylation of o-nitrophenacyl derivatives
作者:Girija Prasad、Patrick E. Hanna、Wayland E. Noland、Shankar Venkatraman
DOI:10.1021/jo00025a047
日期:1991.12
Iron(II) Bromide-Catalyzed Intramolecular C–H Bond Amination [1,2]-Shift Tandem Reactions of Aryl Azides
作者:Quyen Nguyen、Tuyen Nguyen、Tom G. Driver
DOI:10.1021/ja3113565
日期:2013.1.16
Iron(II) bromide catalyzes the transformation of ortho-substituted arylazides into 2,3-disubstituted indoles through a tandem ethereal C-H bond amination [1,2]-shift reaction. The preference for the 1,2-shift component of the tandem reaction was established to be Me < 1° < 2° < Ph.
溴化铁 (II) 通过串联醚 CH 键胺化 [1,2] 转移反应催化邻位取代的芳基叠氮化物转化为 2,3-二取代的吲哚。对串联反应的 1,2-转变组分的偏好确定为 Me < 1° < 2° < Ph。
Total Synthesis of 4,5-Didehydroguadiscine: A Potent Melanogenesis Inhibitor from the Brazilian Medicinal Herb, <i>Hornschuchia obliqua</i>
The first total Synthesis of the 7,7-dimethylaporphinoid, 4,5-didehydroguadiscine (6), originally isolated from the stems and roots of Hornschuchia oblique (Annonaceae), was achieved by the condensation of homopiperonylamine (7) with an alpha,alpha-dimethylphenylacetic acid derivative (8) and subsequent Pschorr reaction of the resulting benzylisoquinoline intermediate (22). The reported C-13 NMR data were partially revised on the basis of the analysis of HMBC spectra measured under different conditions. The melanogenesis inhibitory activity (IC50 = 4.7 mu M) of 6 was 40 times stronger than that of arbutin (174 mu M), which was used as reference standard. Furthermore, 6 was the most potent natural melanogenesis inhibitor Within this class of compounds.