Indoloquinoline cryptolepine

Fig. 1. HMQC spectrum of a 12 pig (0.05 pmol) sample of the indoloquinoline alkaloid cryptolepine (1) dissolved in 145 pL of d6-DMSO. The data were recorded overnight (16 h) at 500 MHz using a 3 mm micro-inverse-detection NMR probe.6 Both a proton reference spectrum (top trace) and the projection through the Fi frequency domain (bottom trace) are shown above the contour plot. (Reprinted with permission from Ref. 6. Copyright 1992, American Chemical Society and American Society of Pharmacognosy.)...

Fig. 3. Photograph showing 5, 3, and 1.7 mm NMR tubes each containing 1 pmol of the deep violet-colored indoloquinoline alkaloid cryptolepine (3).

Fig. 4. Spectra acquired for a 0.55 pmol sample of the indoloquinoline alkaloid cryptolepine (1) dissolved in 25 pL J6-DMSO. (a) Proton-carbon (HMQC) direct correlation spectrum recorded in 12m (16 x 2048 point files, 16 transients/ increment) shown with no linear prediction, (b) Long-range 1H-13C HMBC spectrum of the same sample optimized for 8 Hz. The data were acquired as 64 x 4096 files with 16 transients accumulated/ increment. Data are again shown without any linear prediction. (Reprinted with permission from Ref. 11. Copyright 1998, John Wiley Sons, Ltd.)...

The authors have also extensively studied the indoloquinoline families of alkaloids related to cryptolepine (indolo[3,2-fo]quinoline 57), applying direct and long-range... 

Three members of the relatively rare indoloquinoline family of alkaloids have been studied by the authors. These include cryptolepine (13), quindo-line (3), and the complex spiro-nonacyclic alkaloid cryptospirolepine (1). 

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