Crystal structure of the possible sulindac impurity 2-(5-fluoro-2-methyl-1-inden-3-yl)aceto-nitrile.

The title compound,CHFN, was identified as a possible critical degradation impurity of sulindac, a therapeutic COX-2 inhibitor for rheumatoid arthritis. Single-crystal X-ray analysis revealed two conformationally slightly different mol-ecules in the asymmetric unit (' = 2), each containing an indene ring system. In the crystal structure, [100] chains formed through C-H⋯N inter-actions are connected into a tri-periodic supra-molecular structure by further C-H⋯F and C-H⋯π inter-actions through 2/ symmetry operations.