oxyacanthine

Description

This alkaloid was first obtained by Hesse from Berberis vulgaris and is also a minor constituent of other Berberis and Mahonia species. When recrystallized from EtOH it forms clusters of colourless needles, m.p. 208-214°C, the higher melting point given above being obtained in vacuo. It has [α]_D + 131.6° (CHC13), a much higher value of + 279° (CHCI3) being given by Gericke and Bruchhausen. The dihydrochloride forms needles, m.p. 270-1°C (vac.); [α] ⁺²⁹ _D+ 188.5° (H20) and is only sparingly soluble in dilute HC1; the hydrobromide has m.p. 273-5°C (dec., vac.) and the nitrate forms colourless needles, m.p. 195- 200°C (dec.). The presence of the phenolic hydroxyl group is indicated by the formation of an O-benzoy1 derivative, a potassium salt and the O-methyl ether, giving a hydrochloride, m.p. 261°C. The structure has been deduced from chem_x0002_ical and spectroscopic data. Various colour reactions have been described, e.g. the alkaloid is not coloured by H2S04, gives a yellow colour with HN03 and with molybdic acid in H2S04 produces a violet colour, slowly changing to yellow-green.

Definition

ChEBI: A macrocycle that is oxyacanthan that is substituted by methoxy groups at positions 6, 6', and 7, methyl groups at positions 2 and 2', and a hydroxy group at the 12' position.