Asymmetric synthesis of myrioxazines A and B, novel alkaloids of Myrioneuron nutans
作者:Van Cuong Pham、Akino Jossang、Angèle Chiaroni、Thierry Sévenet、Bernard Bodo
DOI:10.1016/s0040-4039(02)01771-9
日期:2002.10
Two new epimeric tricyclic alkaloids, myrioxazines A and B were isolated from the leaves of Myrioneuron nutans and their structures elucidated by spectral analysis (mass spectrometry and 2D NMR). Absolute configurations were determined by total asymmetric synthesis.
Proton magnetic resonance studies of compounds with bridgehead nitrogen. Part 39. Stereochemistry of perhydropyrido[3,2,1-ij][3,1]benzoxazines and the conformational equilibrium for perhydropyrido[1,2-c][1,3]oxazine
作者:Trevor A. Crabb、Christopher H. Turner
DOI:10.1039/p29800001778
日期:——
The four diasteroisomeric perhydropyrido[3,2,1-ij][3,1]benzoxazines have been synthesised and their configurations assigned by 1H n.m.r. and i.r. spectroscopy and by kinetic studies of N-methylation. Comparisons of the 1H n.m.r. chemical shifts of protons α to nitrogen in these isomers suggested an equilibrium (CDCl3, 25°) for perhydropyrido[1,2-c][1,3]oxazine containing ca. 90% of the trans-fused
合成了四种非对映异构的全氢吡啶并[3,2,1- ij ] [3,1]苯并恶嗪,并通过1 H nmr和红外光谱以及N-甲基化的动力学研究确定了它们的构型。所述的比较1个NMR质子的化学位移Hα在这些异构体氮建议的平衡(CDCL 3为全氢化吡啶并[1,2,25°)c ^ ] [1,3]恶嗪含约 90%的反式融合构象体。
Structure and Total Synthesis of (−)-Myrionidine and (−)-Schoberine, Antimalarial Alkaloids from <i>Myrioneuron nutans</i>
作者:Van Cuong Pham、Akino Jossang、Philippe Grellier、Thierry Sévenet、Van Hung Nguyen、Bernard Bodo
DOI:10.1021/jo801046j
日期:2008.10.3
Two new alkaloids, (5S,9S,10R)-myrionidine (1) and (5S,9S,10R,13S)-myrionamide (2), along with the known schoberine (3), were isolated from the leaves of Myrioneuron nutans (Rubiaceae), and their structures were determined from spectral analysis, including mass spectrometry and 2D NMR. The total asymmetric syntheses of (-)-myrionidine (1), (-)-schoberine (3), their enantiomers as well as their 9-epimers