Andransinine: an unusual case of spontaneous resolution in an indole alkaloid derivative.
Racemic andransinine (1), an indole alkaloid derivative obtained during isolation of alkaloids from Alstonia angustiloba and Kopsia pauciflora, was found to undergo spontaneous resolution when crystallized in EtOAc, forming racemic conglomerates (an equimolar mechanical mixture of enantiomerically pure individual crystals). X-ray analyses of the enantiomers (obtained from crystals from EtOAc solution and from chiral-phase HPLC) provided the absolute configuration of each enantiomer as (15R,16S,21R)-(+)-andransinine (1a or I+) and (15S,16R,21S)-(-)-andransinine (1b or I-).
Department of Chemistry, Faculty of Science, University of Malaya , 50603 Kuala Lumpur, Malaysia.
Yun-Yee
YY
Low
Chew-Yan
CY
Gan
Toh-Seok
TS
Kam
D031051:Alstonia / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D018360:Crystallography, X-Ray; D006801:Humans; D026121:Indole Alkaloids / Q000737:chemistry / Q000302:isolation & purification*; D008968:Molecular Conformation; D015394:Molecular Structure; D013237:Stereoisomerism
D026121:Indole Alkaloids; C000591098:andransinine