KREYSIGININE

Description

A homoaporphine alkaloid isolated from Kreysigia multiflora Reichb., the alka_x0002_loid crystallizes from Et20 or EtOH as colourless prisms. It is dextrorotatory with [α]²⁴_D + 89° (c 1.98, EtOH). The ultraviolet spectrum in EtOH shows two absorption maxima at 218 and 274 mlJ.. Both the hydrobromide, m.p. l42-3°C and the methiodide are crystalline. The latter has an indefinite melting point after softening around 150°C. The methiodide forms orthorhombic crystals with unit cell dimensions of a = 8.366, b = 16.349 and c = 18.606 A with four molecules in the unit cell and space group P2 12121 . The absolute chirality is the same as that of Androcymbine (q.v.). The skeletal structure of the alkaloid has been determined, independently of X-ray analysis, from a detailed study of the 100 MHz NMR spectrum using the double resonance technique.

References

Badger, Bradbury., J. Chem. Soc., 445 (1960)
Structure and absolute chirality:
Fridrichson, MacKay, Mathieson., Tetrahedron Lett., 2887 (1968)
NMR spectra:
Hart et aI., Tetrahedron Lett., 2891 (1968)