organic compounds
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The asymmetric unit of title compound, C12H12N2O4, consists of two independent molecules. In each molecule, the oxadiazine ring has a flattened envelope conformation with the methylene C atom as the flap atom, and the ethoxycarbonyl unit is in a syn-periplanar conformation with respect to the oxadiazine ring as indicated by O—C—C=O torsion angles of 1.9 (4) and 2.5 (4)°. The dihedral angles between the mean plane of the oxadiazine ring and the phenyl ring are 80.07 (13) and 42.98 (14)°. In the crystal, molecules are linked by C—HO hydrogen bonds and stacked in a double-column along the a-axis direction.