Absolute configuration determination of angular dihydrocoumarins from Peucedanum praeruptorum
Titel:
Absolute configuration determination of angular dihydrocoumarins from Peucedanum praeruptorum
Auteur:
Lou, Hong-xiang Sun, Long-ru Yu, Wen-tao Fan, Pei-hong Cui, Lei Gao, Yan-hui Ren, Dong-mei Ji, Mei
Verschenen in:
Journal of Asian natural products research
Paginering:
Jaargang 6 (2004) nr. 3 pagina's 177-184
Jaar:
2004-09
Inhoud:
From Peucedanum praeruptorum, one new khellactone ester (3'R)-O-acetyl-(4'S)-O-angeloylkhellactone (3), as well as four known angular dihydropyranocoumarins (1, 2, 4, 5) have been isolated. On the basis of NMR spectra and X-ray crystallography, their structures were determined. We have elucidated their absolute configuration by either chiral separation of their alkaline hydrolysis products with Rp-18 HPLC eluted with 5% hydroxypropyl-β-cyclodextrin (β-HCD) or by measurement of their CD spectra. A general rule relating the position and absolute stereochemistry of the khellactone esters to the sign of their Cotton effects in CD curves is proposed.