Reinvestigation of the alkaloids of Lupinus sericeus Pursh. Identification of a new natural product, 10,17-dioxo-.beta.-isosparteine

Abstract

0 5 10 15 20 25 TIME HOURSFigure 4. Rate of reaction of nifluridide at pH 9.0 with the formation of EL-919.balance was obtained by adding together the concentrations of nifluridide and EL-919 (as its nifluridide molecular weight equivalent). RESULTS AND DISCUSSIONThe rapid conversion of nifluridide to EL-919 proceeds as indicated in Figure 1. The rates of disappearance and the corresponding formation of EL-919 are plotted on a semilogarithmic scale in Figures 2-4. The cyclization proceeded via a first-order reaction with half-lives of 15.5, 3.5, and 2.0 h for EL-468 at pH 5.0, 7.0, and 9.0, respectively. The total amount of nifluridide and EL919 present in the final samples analyzed provided a good material balance (80-100%) compared to the initial amount of chemical in the aqueous solutions (Figures 2-4). No other hydrolysis products were observed.On the basis of these results, nifluridide would likely dissipate very rapidly in natural water or in the presence of soil moisture. Thus, the parent compound would not be expected to persist in the environment.Chromatograms demonstrating the determination of both compounds in the aqueous solutions are shown in Figure 5. The direct injection of the solutions into the reverse-phase HPLC system at specified intervals, which were programmed into the WISP, provided an automated rate study by eliminating the need to extract the buffered solutions with a suitable solvent, concentrate the sample U W ----0 5 10 15 0 5 10 15 0 5 10 15 0 5 10 15 c TIME, MINUTES Figure 5. Chromatograms demonstrating the dissipation of nifluridide and the formation of EL-919 at pH 9.0 (A) nifluridide standard, 0.8 pg; (B) EL-919 standard, 0.8 pg; (C) reaction solution at 2 h (45.8% nifluridide, 49.1% EL-919); (D) reaction solution a t 10 h (2.9% nifluridide, 105.7% EL-919).extract, and redissolve the residue in a suitable solvent for injection into the HPLC. It is probable that this direct injection technique could also be applied to many other compounds of environmental interest that are highly labile in aqueous solution.

A Two-Directional Synthesis of (+)-β-Isosparteine

“… The enantiomers of sparteine are valued by organic chemists for a diversity of applications as chiral diamines in asymmetric synthesis, although supply issues have stimulated interest in the development of surrogates. , Reported bioactivity is also dominated by the more available stereoisomer, and (−)-sparteine even found clinical applications, for example as an oxytocic agent, , although its FDA approved drug status was withdrawn due to safety concerns. Comparatively less is known about the more scarce C 2 symmetrical isomers in terms of either pharmacology or synthetic applications as ligands. , There have been racemic total syntheses of α- and β-isosparteine, and enantiomerically enriched α- and β-stereoisomers have been obtained from synthetic conversions of other sparteine alkaloids. − …”