Three pairs of alkaloid enantiomers from the root of Isatis indigotica

• Published in: Acta pharmaceutica Sinica. B Vol. 6; no. 2; pp. 141 - 147
• Main Authors: Liu, Yufeng, Wang, Xiaoliang, Chen, Minghua, Lin, Sheng, Li, Li, Shi, Jiangong
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier 01.03.2016
• Subjects: 2-Oxo-1,2,3,4-tetrahydroquinoline-4-carboxylic acid; 3-Thioxohexahydro-1H-pyrrolo[1,2-c]imidazol-1-one; acid;Indolo[2,1-b]quinazolinone;3-Thioxohexahydro-1H-pyrrolo[1,2-c]imidazol-1-one; Alkaloid enantiomer; Chiral separation; Cruciferae; Cruciferae;Isatis; enantiomer;Chiral; indigotica;Alkaloid; Indolo[2,1-b]quinazolinone; Isatis indigotica; Original; separation;2-Oxo-1,2,3,4-tetrahydroquinoline-4-carboxylic; Indolo[2,1-b]quinazolinone; Alkaloid enantiomer; 3-Thioxohexahydro-1H-pyrrolo[1,2-c]imidazol-1-one; Cruciferae; Isatis indigotica; Chiral separation; 2-Oxo-1,2,3,4-tetrahydroquinoline-4-carboxylic acid
• ISSN: 2211-3835; 2211-3843
• DOI: 10.1016/j.apsb.2016.01.003

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.