2,2-Dimethyl-5-(2-nitro­benzyl­idene)-1,3-dioxane-4,6-dione

The asymmetric unit of the title compound, C₁₃H₁₁NO₆, contains two mol­ecules in both of which the six-membered 1,3-dioxane-4,6-dione ring shows a screw-boat conformation. The dihedral angles between the best planes through the six-membered rings are 47.8 (2) and 49.8 (2)°. In the crystal, C—H...O inter­actions link the mol­ecules, building a supramolecular sheet parallel to the c axis.