摘要
Three pairs of enantiomerically pure alkaloids with diverse structure features, named isatindigoticoic acid A and epiisatindigoticoic acid A [(—)-1 and(+)-1], phaitanthrin A and epiphaitanthrin A [(—)-2 and(+)-2], and isatindopyrromizol A and epiisatindopyrromizol A [(—)-3and(+)-3], respectively, were isolated from an aqueous extract of the roots of Isatis indigotica. Racemic and scalemic mixtures of these enantiomers were separated by HPLC on a chiral semi-preparative column.Their structures including absolute configurations were determined by extensive spectroscopic analysis in conjunction with the calculation of electronic circular dichroism(ECD) spectra. The enantiomer pairs possess parent structures of 2-oxo-1,2,3,4-tetrahydroquinoline-4-carboxylic acid, indolo[2,1-b]quinazolinone, and 3-thioxohexahydro-1H-pyrrolo[1,2-c]imidazol-1-one, respectively. Except for phaitanthrin A[(—)-2] which the configuration was previously undetermined, these compounds are new enantiomeric natural products.
Three pairs of enantiomerically pure alkaloids with diverse structure features, named isatindigoticoic acid A and epiisatindigoticoic acid A [(-)-1 and (+)-1], phaitanthrin A and epiphaitanthrin A [(-)-2 and (+)-2], and isatindopyrromizol A and epiisatindopyrromizol A [(-)-3 and (+)-3], respectively, were isolated from an aqueous extract of the roots of Isatis indigotica. Racemic and scalemic mixtures of these enantiomers were separated by HPLC on a chiral semi-preparative column. Their structures including absolute configurations were determined by extensive spectroscopic analysis in conjunction with the calculation of electronic circular dichroism (ECD) spectra. The enantiomer pairs possess parent structures of 2-oxo-1,2,3,4-tetrahydroquinoline-4-carboxylic acid, indolo[2,1-b]quinazolinone, and 3-thioxohexahydro-1H-pyrrolo[1,2-c]imidazol-1-one, respectively. Except for phaitanthrin A [()-2] which the configuration was previously undetermined, these compounds are new enantiomeric natural products. (C) 2016 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.
基金
Financial support from the National Natural Sciences Foundation of China (NNSFC
Grant Nos. 81373287 and 30825044)
the Beijing Excellent Talent Training Project (Grant No. 2013D009008000002)
the National Science and Technology Project of China (Nos. 2012ZX09301002-002 and 2011ZX0 9307002-01)
