Crystal Structure of Guanfacine Hydrochloride

Abstract

The crystal of the title antihypertension agent, C₉H₉Cl₂N₃O·HCl, belongs to space group Pbcn with the cell dimensions a = 14.439(3), b = 8.366(2), and c = 39.656(8)Å. The final R value is 0.064. Two crystallographically independent molecules take different conformations. Both structures are non-planar, the dihedral angles between the phenyl rings and the least-squares planes defined by the guanidine moieties are 92.4(4) and 74.9(4)°. There are strong intramolecular N-H…O hydrogen bonds in both molecules.