An X-Ray Determination of the Structure of Chamaecynenol

Abstract

Abstract Crystals of chamaecynenol 4-bromo-3-nitrobenzoate, C21H22O4NBr, are monoclinic, with two molecules in a unit cell of the dimensions, a=10.47, b=14.08, c=6.75Å, and β=101.8° and with the space group of P21. The intensities were recorded on multiple-film equi-inclination Weissenberg photographs and measured visually with a standard scale. The structure was determined by the heavy atom method. The positional and thermal parameters were refined by the least-squares method. The final R factor for the observed reflections is 0.090. The absolute configuration was also determined using anomalous dispersion effect of the bromine atom. It was thus established that chamaecynenol is 7β-ethynyl-4β-hydroxymethyl-10β-methyl-Δ1-cis-octaline in the steroid conformation.