3-(2,6-Dioxopiperidin-3-yl)-3-aza-bicyclo-[3.2.0]heptane-2,4-dione.

The title mol-ecule, C(11)H(12)N(2)O(4), consists of a 3-aza-bicyclo-[3.2.0]heptane group containing a nearly planar cyclo-butane ring (r.m.s. deviation of fitted atoms is 0.0609 Å), fused to a pyrrolidine ring, bonded to a 2,6-dioxopiperidine ring at the 3-position. The angle between the mean planes of the cyclo-butane and fused pyrrolidine ring is 67.6 (6)°. The dihedral angles between the mean planes of the pyrrolidine and cyclo-butane rings and the dioxopiperidine ring are 73.9 (2) and 62.4 (4)°, respectively. The pyrrolidine and dioxopiperidine rings are twisted about the 3-yl group [torsion angles = -55.0 (1) and 115.0 (1)°] in a nearly perpendicular manner. Crystal packing is influenced by extensive inter-molecular C-H⋯O and N-H⋯O inter-actions between all four carbonyl O atoms and H atoms from the cyclo-butane and dioxopiperidine rings, as well as between the N atom and an H atom from the cyclo-butane ring. In addition, weak π-ring interactions also occur between H atoms from the cyclobutane ring and the five-membered pyrrolidine ring. As a result, mol-ecules are linked into infinite chains diagonally along the [101] plane of the unit cell in an alternate inverted pattern.