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。