Stereochemistry of anticholinergic agents. Part II. Crystal and molecular structure of glycopyrronium bromide

Abstract

Crystals of the title compound are orthorhombic, space group Pbca, with Z= 8 in a cell of dimensions a= 12·06 ± 0·01, b= 33·27 ± 0·02, c= 9·63 ± 0·01 Å. The structure was determined by Patterson and Fourier methods by use of three-dimensional X-ray counter-data, and refined by least squares to R 8·0% for 1783 structure amplitudes. Estimated standard deviations for bond lengths, bond angles and torsion angles average 0·016 Å, 0·8°, and 1·0°. In the glycopyrronium cation the two five-membered rings each adopt the envelope conformation, and the acetylcholine-like moiety adopts a conformation similar to that of acetylcholine in crystals of the bromide salt.