(3β,7R,16E)-16,17-Didehydro-9-hydroxy-17-methoxy-2-oxocorynoxan-16-carboxylic acid methyl ester

The leaves of Mitragyna speciosa Korth contain this alkaloid which crystallizes from EtOH in colourless needles. It is laevorotatory with [α]²²_D - 103° (c 2.0, CHCI3). The ultraviolet spectrum has absorption maxima at 223, 242 and 290 mJ.1. The alkaloid has been shown to be a stereoisomer of rotundifoline (q.v.).

Beckett, Lee, Tackie., Tetrahedron Lett., 1709 (1963)