1-(3-Chlorobenzyl)-5-iodoindoline-2,3-dione

In the title compound, C15H9ClINO2, which possesses anticonvulsant activity, the iodoindoline ring system is essentially planar (maximum deviation 1.245 Å) and is oriented with respect to the 3-chlorobenzyl ring at a dihedral angle of 76.59 (3)°. In the crystal, there is a π–π contact between iodoindoline ring systems [centroid–centroid distance = 3.8188 (4) Å].

In the title compound, C 15 H 9 ClINO 2 , which possesses anticonvulsant activity, the iodoindoline ring system is essentially planar (maximum deviation 1.245 Å ) and is oriented with respect to the 3-chlorobenzyl ring at a dihedral angle of 76.59 (3) . In the crystal, there is acontact between iodoindoline ring systems [centroid-centroid distance = 3.8188 (4) Å ].

Comment
Indolinones are a class of heterocyclic compounds found in many natural products and in a number of marketed drugs (Hibino & Choshi, 2002;Somei & Yamada, 2003). They have diverse chemical structures and complex physiological and pharmacological actions. The search for potential drugs and their mechanism of action has been difficult because of their complexity. These compounds contain both oxoindole and dioxolane moieties which have independently been seen in other anticonvulsants (Popp, 1977(Popp, , 1984. The title compound, a chloro analogue, was found to be most potent in the MES test.
Since no common target site has yet been established, X-ray analysis was undertaken to search structural information which may help in the understanding of the mechanism of action at the molecular level.

Experimental
A mixture of 5-iodoisatin (1.8 g, 10 mmol) and 3-chlorobenzyl chloride (1.6 g, 10 mmol) was refluxed in DMF (50 ml) in the precense of potassium carbonate for 6 h. DMF was removed from the reaction mixture by distillation. Ice cold water (20 ml) was added and the reaction mixture was extracted with dichloromethane (3 × 20 ml). The extract was dried and evaporated to yield the crude solid, which was recrystallized from methanol (yield; 74%; m.p. 411-412 K).

Refinement
H atoms were positioned geometrically, with C-H = 0.93 and 0.97 Å for aromatic and methylene H, respectively, and constrained to ride on their parent atoms with U iso (H) = 1.2U eq (C). Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids drawn at the 50% probability level.