Enantiomeric separation of angular-type pyranocoumarins from Peucedani Radix using AD-RH chiral column

Enantiomers and diastereoisomers of angular-type pyranocoumarins (APs) are abundant in Peucedani Radix (Chinese name: Qian-hu), eliciting distinct activities in vitro and in vivo. Our ongoing investigation on APs yielded eight pairs of enantiomers (1a and 1b, 2a and 2b, 3a and 3b, 4a and 4b, 5a and 5b, 6a and 6b, 7a and 7b and 8a and 8b) via enantiomeric separation of trans-3'-angeloylkhellactone (1), trans-3'-acetyl-4'-isobutyrylkhellactone (2), trans-3'-acetyl-4'-angeloyl-khellactone (3), 3'-angeloyloxy-4'-oxo-3',4'-dihydroseselin (4), cis-3'-acetyl-4'-angeloylkhellactone (5), cis-3'-isovaleryl-4'-acetylkhellactone (6), cis-3'-angeloyl-4'-isovalerylkhellactone (7) and cis-3',4'-diisovalerylkhellactone (8), respectively, using semi-preparative AD-RH chiral column. All the compounds (1-8) were enantioseparated for the first time, while the absolute configurations of 2a, 2b, 6a and 8b were reported first.