Crystal structure of 3-(3-oxo-2,3,4,4a,5,6-hexahydrobenzo[h]cinnolin-2-yl)propionic acid

The asymmetric unit of the title compound, C15H16N2O3, contains two independent molecules, which present a different conformation of the carboxylic acid side chain [C-C-C-OH torsion angles = 65.3(7) and -170.1(5)°]. In both molecules, the dihydropyridazinone ring adopts a geometry intermediate between a twisted-boat and a half-chair conformation, while the central six-membered ring is almost in a half-boat conformation. In the crystal, molecules are linked by O-H⋯Ok (k = ketone) hydrogen bonds, generating [01-1] chains. Aromatic π-π stacking contacts between the benzene and the dihydropyridazinone rings [centroid-centroid distance [3.879(9)Å] are also observed.