An enantiomerically pure bilirubin. Absolute configuration of (αR,α′R)-dimethylmesobilirubin-XIIIα
作者:Stefan E. Boiadjiev、David A. Lightner
DOI:10.1016/s0957-4166(01)00455-4
日期:2001.10
accomplished in three crystallizations, and the absolute configuration of the acid 6 was deduced by X-ray crystallography of the more crystalline, diastereomerically pure amide 7. Circular dichroism spectroscopy of 1 showed intense bisignate Cotton effects: Δεmax435=+344, Δεmax391=−193 (CHCl3), as expected for a molecular exciton, and consistent with a P-helical intramolecularly hydrogen-bonded ridge-tile
对映体纯(+) - (α - [R,α' - [R)-dimethylmesobilirubin-XIIIα 1和它的(α小号,α'小号)对映体ENT - 1中,从简单的前体十步合成。在合成的早期阶段就实现了拆分,外消旋单吡咯前体rac - 6用(1 S)-樟脑-2,10-杜马酰胺转化为酰胺8。在三个结晶中完成了8至99%de的拆分,酸6的绝对构型通过X射线晶体学推论出结晶度更高,非对映异构纯的酰胺7。的圆二色光谱1显示强烈bisignate棉效果:Δ ε最大435 = + 344,Δ ε最大391 = -193(氯仿3),如所预期为一个分子激子,并具有一致的P螺旋分子内氢键键合的脊-tile构象。的顿效应幅度1个匹配几乎完全那些发现( - ) - (β小号,β'小号)-dimethylmesobilirubin-XIIIα 11和(+) - (α - [R,β' - [R)-二甲基间胆红