Crystal and molecular structure of sceletium alkaloid A4 by X-ray analysis

Abstract

Sceletium Alkaloid A₄, (1), C₂₀H₂₄N₂O₂, isolated from Sceletium namaquense L. Bolus crystallizes in the monoclinic system, space group P2₁, with a= 8·33(2), b= 14·74(3), c= 7·18(2)Å, β= 95·04(20)°, and Z= 2. The structure was solved from photographic X-ray data by direct phase-determining methods and refined by full-matrix least-squares calculations to R 0·100 over 1523 observed reflexions. The alkaloid which contains a 2,3-disubstituted pyridine moiety is representative of a third structure variant in Sceletium species.