Flukicides. IV. Crystal and Molecular Structure of 3'-Chloro-4'(p-chlorophenoxy)-3,5-diiodo-salicylanilide (Rafoxanide)

Abstract

Orthorhombic crystals of rafoxanide, C₁₉H₁₁Cl₂I₂NO₃, belong to the space group Pca2₁ with a 23.234(2), b 8.980(2), c 9.582(2)Ǻ and Z 4. The structure was solved by the heavy-atom method from diffractometer data measured with Mo Kα radiation. Refinement with anisotropic temperature factors given to the non-hydrogen atoms converged at R 0.059 for the 2025 observed terms. The two aromatic rings of the salicylanilide moiety are almost coplanar with a dihedral angle of 11.2°, whereas they are approximately perpendicular to the plane of the phenoxy group. Weak inter-molecular hydrogen-bond-like interactions between the nitrogen and carbonyl oxygen, which involve a glide motif, link the molecules into ribbons extending along the c axis.