Crystal and molecular structure of ibogamine: An alkaloid from Stemmadenia galeottiana

Abstract

C19H24N2 is orthorhombic, D24-P212121. Unit cell dimensions at 293 K are a=10.346(7), b=10.464(3), c=29.083(10)Å, V=3149(4) Å3, Dc=1.18 g cm-3, and Z=8. The structure has been determined from single-crystal data collected with a four-circle diffractometer and refined from 1968 reflections down to R=0.045 and ωR=0.047. The structural features determined from chemical and spectroscopic studies are confirmed and extended. There are two crystallographically independent molecules (A and B). In both A and B molecules the indole ring system is planar and attached to a seven-membered nitrogen-containing ring with a distorted-chair conformation. The indole and seven-membered rings lie close to the same plane [dihedral angles are 6.6(5) and 4.1(5)° for the A and B molecules, respectively], while the C(5)-N(6)-C(19)-C(2) atoms of the central axis of the iso-quinuclidine tricyclic structure are almost perpendicular to seven-membered ring [dihedral angles are 84.7(5) and 87.9(5)° for the A and B molecules, respectively]. The A and B molecules in the crystal are packed at normal van der Waals distances. © 1988 Plenum Publishing Corporation.