Description
This lobeline alkaloid occurs in Lobelia inflata L. and to a lesser extent in L.
sessiliflora. It crystallizes from EtOH in colourless laminae, distils unchanged in
vacuo and is freely soluble in Me2CO or C6H6 but only sparingly so in Et20. It
forms a series of crystalline salts and derivatives: the hydrochloride, m.p. 135-
8°C; hydrobromide, l88-l90°C; methiodide, m.p. l73-SoC at which temperature it becomes turbid but clearing at 199-200°C; the dibenzoyl derivative, m.p.
109-1 10°C, forming a hydrochloride, m.p. 239-240°C (dec.) and the diacetate,
m.p. 214-SoC, giving a hydrochloride, m.p. 21S-6°C and an acetate, m.p. 75°C.
With POCl3 the alkaloid gives dichlorolobelane, m.p. IS8-9°C which yields lobelane, m.p. 175°C (high vacuum) on methylation. On oxidation with KMn04
in H2S04, the alkaloid furnishes (±)-lobeline.
References
Wieland, Dragendorff., Annalen, 473,83 (1929)
Wieland, Koschara, Dane., ibid, 473, 118 (1929)
Schuing, Winterhalder., ibid, 473, 126 (1929)
Wieland, Schopf, Hermsen., ibid, 444, 60 (1925)
