The structure of the title molecule, C9H7NO2, has been redetermined to improved precision and the H atoms located [Cannaset al.(1969).Acta Cryst.B25, 1050]. The five-membered ring is almost planar (r.m.s. deviation = 0.006 Å) and subtends a dihedral angle of 2.45 (6)° with the benzene ring. In the crystal, molecules form ribbons running parallel to thea-axis direction through a combination of C—H...N and C—H...O hydrogen bonds. `Stair-step' offset π–π stacking interactions are also observed.

The title compound, C17H16N2O, consists of a benzodiazepin-2-one moiety substituted with a phenyl ring and an ethyl group. The seven-membered diazepine ring has a boat conformation and the fused benzene ring is nearly perpendicular to the phenyl ring, as indicated by the dihedral angle of 74.90 (8)°. The atoms of the ethyl group are disordered over two sets of sites, with a refined occupancy ratio of 0.603 (15):0.397 (15). In the crystal, molecules are linked by pairs of C—H...O hydrogen bonds, forming inversion dimers. The dimers are linkedviaa further C—H...O hydrogen bond, forming layers parallel to (001), which are in turn linked by C—H...π interactions, forming a three-dimensional structure.

The asymmetric unit of the title compound, C 17 H 14 N 2 O 3 , consists of two independent molecules having distinctly different conformations. The components of the asymmetric unit are connected by an O-HÁ Á ÁN hydrogen bond, with additional O-HÁ Á ÁN hydrogen bonds connecting this assemblage into chains running parallel to the b axis. Intermolecular C-HÁ Á Á(ring) interactions are also present. Structure descriptionAs a continuation of our studies on substituted 1,5-benzodiazepin-2-one derivatives (Essaghouani et al., 2016;Ballo et al., 2010), we report the synthesis of a new 1,5-benzodiazepin-2-one derivative by the hydrolysis reaction with an aqueous solution of potassium hydroxide of ethyl 2-(2-oxo-4-phenyl-2,3-dihydro-1H-1,5-benzodiazepin-1-yl)acetate in ethanol.The asymmetric unit (Fig. 1) consists of two independent molecules which differ markedly in their conformations. This can be seen, in part, from the puckering parameters for the seven-membered rings. For the ring N1,C1,C6,N2,C7,C8,C9, Q(2) = 0.881 (1) Å , Q(3) = 0.218 (1) Å , '(2) = 203.79 (7) and '(3) = 307.7 (3) with a total puckering amplitude of 0.907 (1) Å , while for the ring N3,C18,C23,N4,C24,C25,C26, the corresponding values are 0.904 (1) Å , 0.234 (1) Å , 25.64 (7) and 125.9 (3) with a total puckering amplitude of 0.934 (1) Å . Additionally, the dihedral angle between the C1-C6 and C12-C17 rings is 72.18 (4) while that between the C18-C22 and C29-C34 rings is 80. 03 (4) .

In the crystal, the title molecule, C10H9N3O2, packs in layers approximately parallel to (100), which are formed by the association of zigzag chains constructed by weak C—H...O interactions. The allyl group is disordered over two positions, with a ratio of their occupancies close to 70:30.

In the title compound, C9H7N3O3, paired ribbons of molecules running in thea-axis direction are formed by intermolecular C—H...O and offset π-stacking interactions.