Amaryllidaceae alkaloids. Part II. Crystal structure of tazettine methiodide

Abstract

The crystal structure of tazettine methiodide, C₁₈H₂₁NO₅·CH₃l(+CH₃OH), has been determined by a three-dimensional X-ray analysis. The crystals are monoclinic, a= 13·162, b= 10·387, c= 7·759 Å, β= 95° 22′, Z= 2, and space group P2₁. The intensities were measured with an automatic four-circle diffractometer using Mo-K_α radiation. The structure was solved by the programme SEARCHER, for the automatic heavy-atom analysis, and refined by full-matrix least-squares calculations to a final R of 0·051 for 2261 independent observed reflexions. The absolute configuration was determined by the anomalous dispersion method.