THREE MINOR ALKALOIDS OF GELSEMIUMSEMPERVIRENS AIT.

Abstract

After the removal of gelsemine and sempervirine from the extract of the root of Gelsemizirn se7nperuirens Ait. the residual alkaloids left in the mother liq~lors were berizoylated. I t was thus possible to separate the tertiary bases from the secondary bases which were obtained as a rnixture of the neutral benzoyl derivatives. Puritication by chromatography yielded the benzoylated mixture in crystalli~ie form. This was hydrolyzed and the recovered secondary bases were separated by fractional crystallization of the perchlorates into alkaloid A and alkaloid B.Allcaloid A was shown by direct conlparison to be identical with the gelsemicinr

Coinage Metal Complexes of a Tellurium Diimide:cis→trans Isomerization and Metal-Metal Interactions

“…[1] The versatile ligand behavior of sulfur(iv) diimides encompasses s(N), s(N,N'), and, less commonly, s(S) and p(N,S) bonding modes. [2] The only known complex of a selenium(iv) diimide, SnCl 4 (tBuNSeNtBu), displays s(N,N') chelation. [3] Unlike their lighter congeners RNENR (E S, Se), which adopt monomeric structures with syn,syn or syn,anti conformations in the solid state [4,5] and gas phase, [6] tellurium diimides are dimeric and form cis or trans isomers in the solid state.…”

Total Synthesis of (+)-Gelsedine

“…In fact, extracts from Gelsemium species have a rich medicinal history, particularly in China. [1] Gelsedine (2) was isolated from Carolina jasmine (Gelsemium sempervirens) in 1953 by Schwarz and Marion [4] and was later also found to occur in G. elegans. [5] Its structure was elucidated by Wenkert et al [6] in 1962 on the basis of a spectroscopic comparison with its 11-methoxy analogue gelsemicine (3), whose structure had already been determined in 1961 through X-ray crystallography by Przybylska and Marion.…”

“…[3] Unlike their lighter congeners RNENR (E S, Se), which adopt monomeric structures with syn,syn or syn,anti conformations in the solid state [4,5] and gas phase, [6] tellurium diimides are dimeric and form cis or trans isomers in the solid state.…”

Totalsynthese von (+)-Gelsedin

“…Wir befaûten uns mit den Gelsemium-Alkaloiden wegen ihrer reizvollen Molekülstruktur und den interessanten biologischen Aktivitäten, die einige dieser Naturstoffe aufweisen. Extrakte aus Gelsemium-Arten sind in der Medizin, besonders in der traditionellen Medizin Chinas, [1] seit langem bekannt.Gelsedin 2 wurde 1953 von Schwarz und Marion [4] aus gelbem Jasmin (Gelsemium sempervirens) isoliert und später auch in G. elegans nachgewiesen. [5] Die Struktur wurde 1962 von Wenkert et al [6] durch einen spektroskopischen Vergleich mit dem 11-Methoxy-Analogon Gelsemicin 3 aufgeklärt, dessen Struktur schon 1961 von Przybylska und Marion [7] durch Röntgenstrukturanalyse bestimmt worden war.…”

“…Gelsedin 2 wurde 1953 von Schwarz und Marion [4] aus gelbem Jasmin (Gelsemium sempervirens) isoliert und später auch in G. elegans nachgewiesen. [5] Die Struktur wurde 1962 von Wenkert et al [6] durch einen spektroskopischen Vergleich mit dem 11-Methoxy-Analogon Gelsemicin 3 aufgeklärt, dessen Struktur schon 1961 von Przybylska und Marion [7] durch Röntgenstrukturanalyse bestimmt worden war.…”