ELUCIDATION OF THE STRUCTURE OF QUINDOLINONE, A MINOR ALKALOID OF CRYPTOLEPIS-SANGUINOLENTA - SUBMILLIGRAM H-1-C-13 AND H-1-N-15 HETERONUCLEAR SHIFT CORRELATION EXPERIMENTS USING MICRO INVERSE-DETECTION

Elucidation of minor natural product structures has been significantly augmented by inverse-detection; further improvement has been afforded by the development of micro inverse-detection probes. We report here the elucidation of the structure of a new alkaloid, quindolinone (5H,10H-indolo[3,2-b]quinolin-11-one), from the West African plant Cryptolepis sanguinolenta. All nmr data for this minor, preparative hplc-isolated alkaloid, including H-1-N-15 one-bond heteronuclear shift correlation (HMQC) data, were recorded on an 800 mu g sample of the alkaloid dissolved in 140 mu l of 100% d(6)-DMSO using a 400 MHz spectrometer.