BIOGENETIC-TYPE SYNTHESIS OF THE QUINOLIZIDINE PORTION OF LYTHRACEAE ALKALOIDS

Abstract

N-Chloropiperidine was synthesized by the oxidation of piperidine acetate with sodium hyperchlorite in aqueous solution. After hydrochloride elimination with potassium hydroxide in 95% ethanol, A1 -piperideine was obtained---existed in the trimeric form α-tripiperideine. Condensation of acetoacetic acid with the acidic solution of α-tripiperideine under an inert atmosphere, in a buffer of citric acid and sodium hydrophosphate solution, pelletierine was obtained from the final vacuum distillation. In order to identify and confirm the existence of pelletierine, derivatives were prepared and IR spectrum was taken too. An alternative method, by using lysine hydrochloride as a precursor, was tested over ten times, but the preparation was not successful. Attempted synthesis of 2-oxo-4-(3 1 -benzoyloxy-4 1 -methoxy)-phenylquinolizidine by the condensation of pelletierine and isovanillin benzoate (or vanillin benzoate) using a method with slight modification of the procedure as described by Matsunaga et al. 14 was carried out. The final separation of the resulting mixture was incomplete, and no identifiable product was obtained. But T.L.C. result indicates that there is one major spot which is probably the desired product. The attempted synthesis of 4-phenylquinolizidines was modelled after the biogenetic scheme of Ferris et al. 4 for Lythraceae alkaloids