Crystal structures of 2-meth-oxy-isoindoline-1,3-dione, 1,3-dioxoisoindolin-2-yl methyl carbonate and 1,3-dioxo-2,3-di-hydro-1H-benzo[de]isoquinolin-2-yl methyl carbonate: three anti-convulsant compounds.

The title compounds, C9H7NO3, (1), C10H7NO5, (2), and C14H9NO5, (3), are three potentially anti-convulsant compounds. Compounds (1) and (2) are isoindoline derivatives and (3) is an iso-quinoline derivative. Compounds (2) and (3) crystallize with two independent mol-ecules (A and B) in their asymmetric units. In all three cases, the isoindoline and benzoiso-quinoline moieties are planar [r.m.s. deviations are 0.021 Å for (1), 0.04 and 0.018 Å for (2), and 0.033 and 0.041 Å for (3)]. The substituents attached to the N atom are almost perpendicular to the mean planes of the heterocycles, with dihedral angles of 89.7 (3)° for the N-O-Cmeth-yl group in (1), 71.01 (4) and 80.00 (4)° for the N-O-C(=O)O-Cmeth-yl groups in (2), and 75.62 (14) and 74.13 (4)° for the same groups in (3). In the crystal of (1), there are unusual inter-molecular C=O⋯C contacts of 2.794 (1) and 2.873 (1) Å present in mol-ecules A and B, respectively. There are also C-H⋯O hydrogen bonds and π-π inter-actions [inter-centroid distance = 3.407 (3) Å] present, forming slabs lying parallel to (001). In the crystal of (2), the A and B mol-ecules are linked by C-H⋯O hydrogen bonds, forming slabs parallel to (10-1), which are in turn linked via a number of π-π inter-actions [the most significant centroid-centroid distances are 3.4202 (7) and 3.5445 (7) Å], forming a three-dimensional structure. In the crystal of (3), the A and B mol-ecules are linked via C-H⋯O hydrogen bonds, forming a three-dimensional structure, which is consolidated by π-π inter-actions [the most significant inter-centroid distances are 3.575 (3) and 3.578 (3) Å].