Veratrum alkaloids. Part LVI. Crystal structure and absolute configuration of zygacine acetonide hydriodide acetone solvate

Abstract

A three-dimensional, single-crystal, X-ray analysis of the title compound has confirmed its molecular structure and absolute configuration, and thus the stereochemistry and absolute configurations of the related alkaloids, zygadenine, germine, and protoverine. Crystals are monoclinic, a= 20·484(3), b= 8·828(1), c= 25·208(4)Å, β= 114·55(1)°, space group C2, Z= 4, and there are 8 molecules of acetone of solvation in the unit cell. The structure was solved by the heavy-atom method, and refined by least-squares methods to R 0·093 for 2564 independent reflections measured by counter diffractometry. The absolute configuration was determined by the anomalous dispersion method.