Ethyl 5-oxo-4-phenyl-5,6-di­hydro-4H-1,3,4-oxadiazine-2-carboxyl­ate

The asymmetric unit of title compound, C(12)H(12)N(2)O(4), 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—H⋯O hydrogen bonds and stacked in a double-column along the a-axis direction.