Tronocarpine, a novel pentacyclic indole incorporating a seven-membered lactam moiety

Vobasonidine and Vobatricine, Novel Bisindole Alkaloids from a Malayan Tabernaemontana

“…The NMR spectral data also indicated that the other vobasine unit, except for the presence of a hydroxymethyl substituent at C(16'), corresponds to vobasinol, as suggested by the observed C(3') oxymethine resonance at d 65. 6. The 13 C-NMR spectrum of 2 showed a total of 44 peaks in agreement with the formula derived from mass measurements.…”

Seco-tabersonine alkaloids from Tabernaemontana corymbosa

“…The same plant also yielded a number of new indole and bisindole alkaloids Kam andSim, 2003a,b, 2002a,b,c;Zhang et al, 2007;Zèches et al, 1994), including several vobasinyl-iboga bisindoles which reverse multidrug-resistance in vincristine resistant KB cells (Kam et al, 1998). In continuation of our studies of biologically active alkaloids from Malaysian Tabernaemontana (Kam et al, 2004a(Kam et al, ,b, 2003a(Kam et al, ,b, 2001(Kam et al, , 2000(Kam et al, , 1998(Kam et al, , 1992Kam and Sim, 2003a,b, 2002a,b,c, 2001, 1999, we recently reported the isolation of several new cytotoxic Aspidosperma-type alkaloids, jerantinines AÀG, from the leaf extract of the same species, but involving plant material collected from a different location (Lim et al, 2008). We now wish to report the further isolation of additional new alkaloids from the leaf extract of the same plant.…”

“…In our systematic study of the Malaysian representatives of this genus, we have reported many examples of new alkaloids which are distinguished by their structural novelty, as well as useful bioactivity (Kam et al, 2004a(Kam et al, ,b, 2003a(Kam et al, ,b, 2001(Kam et al, , 2000(Kam et al, , 1998Kam andSim, 2003a,b, 2002a). The Malayan T. corymbosa Roxb.…”

“…The Malayan T. corymbosa Roxb. ex Wall for instance provided several new alkaloids which are characterized by novel molecular skeletons such as the hexacyclic alkaloid, tronoharine , the pentacyclic indole tronocarpine (Kam et al, 2000), and the quinolinic alkaloid, voastrictine . The same plant also yielded a number of new indole and bisindole alkaloids Kam andSim, 2003a,b, 2002a,b,c;Zhang et al, 2007;Zèches et al, 1994), including several vobasinyl-iboga bisindoles which reverse multidrug-resistance in vincristine resistant KB cells (Kam et al, 1998).…”

Recent developments in syntheses of the post-secodine indole alkaloids. Part III: Rearranged alkaloid types

“…(+)-Tronocarpine (1122) is an alkaloid present in Tabernaemontana corymbosa and represents yet another variant of rearranged ibogane skeleton 57 . It was five years before its isolation when Mahboobi and co-workers had synthesized 58 tetracyclic dilactam 1123 which has later on become a popular model target to tronocarpine, Scheme 27.…”