Frédérick Raphaël, Norberg Bernadette, Durant François, Ooms Frederic, Wouters Johan
Laboratory of Molecular and Structural Chemistry, University of Namur, 61 rue de Bruxelles, B-5000 Namur, Belgium.
Acta Crystallogr C. 2004 Sep;60(Pt 9):o623-6. doi: 10.1107/S0108270104014660. Epub 2004 Aug 11.
The structures of three compounds, namely 7-methoxy-2-[3-(trifluoromethyl)phenyl]-9H-indeno[1,2-c]pyridazin-9-one, C19H11F3N2O2, (Id), 6-methoxy-2-[3-(trifluoromethyl)phenyl]-9H-indeno[1,2-c]pyridazin-9-one, C19H11F3N2O2, (IId), and 2-methyl-6-(4,4,4-trifluorobutoxy)-9H-indeno[1,2-c]pyridazin-9-one, C16H13F3N2O2, (IIf), which are potent reversible type-B monoamine oxidase (MAO-B) inhibitors, are presented and discussed. Compounds (Id) and (IId) crystallize in a nearly planar conformation. The crystal structures are stabilized by weak C-H...O hydrogen bonds. The packing is dominated by pi-pi stacking interactions between the heterocyclic central moieties of centrosymmetrically related molecules. In compound (IIf), the trifluoroethyl termination is almost perpendicular to the plane of the ring.
