Crystal structure of a benzimidazole hepatitis C virus inhibitor free and in complex with the viral RNA target.

The crystal structure of 8-((dimethylamino)methyl)-1-(3-(dimethylamino)propyl)-1,7,8,9-tetrahydrochromeno[5,6-d]imidazol-2-amine (1), an inhibitor of the hepatitis C virus internal ribosome entry site, is described and compared to the structure of the compound in complex with the viral RNA target. Compound 1 crystallized by pentane vapor diffusion into dichloroethane solution. It crystallized in the monoclinic system, P21/c space group with unit cell parameters a = 15.7950(5) Å, b = 14.0128(4) Å, c = 8.8147(3) Å, β = 94.357(2)° and a cell volume of 1945.34(11) A-3. Packing interactions in the small molecule crystal lattice correspond to key interactions of the compound with the viral RNA target.