High-Pressure Polymorphism of Ribavirin.

The effect of high pressure on ribavirin, a broad-spectrum antiviral consisting of ribofuranosyl triazole, and carboxamide moieties, has been studied up to ∼10 GPa. Three new high-pressure phases, designated V3, V4 and V5, have been obtained by compression of the ambient-pressure V2 form with structures refined up to 7.5 GPa. The new phases are formed at 5.3, 6.0, and 7.2 GPa, respectively, and crystallize in space group P2(1)2(1)2(1) with Z' = 3, 1, and 1. They are distinguished by changes in the conformation of the ribofuranosyl moiety which impacts both the molecular geometry and the supramolecular structure.