Molecular and crystal structure of 4-ethoxycarbonyloxy-1-oxo-1H-phthalazine-2-carboxylic acid ethyl ester

The molecular and crystal structure of 4-ethoxycarbonyloxy-1-oxo-1H-phthalazine 2-carboxylic acid ethyl ester has been elucidated by X-ray diffraction methods. The compound crystallizes in the orthorhombic crystal system (space group Pc) with the unit cell parameters a = 10.758(9), b = 4.631(3), c = 14.957(7) Å, β = 107.30(6)° and Z = 2. The structure has been solved by direct methods and refined to a final R value of 0.060 for 870 observed reflections F _o > 4σ(F _o)]. The presence of a large number of intra-and intermolecular interactions makes the molecule look like a four-ring structure. The structure is stabilized by C-H···O hydrogen bonds.