4-[2-(2,2-Dimethyl-4,6-dioxo-1,3-dioxan-5-yl­idene)hydrazin-1-yl]benzo­nitrile

In the title compound, C(13)H(11)N(3)O(4), the dioxane ring adopts an envelope conformation with the C atom bonded to the dimethyl group in the flap position [deviation = 0.613 (1) Å]. The nitrile group and the attached benzene ring are roughly coplanar [maximum deviation = 0.087 (1) Å]. An intra­molecular N—H⋯O hydrogen bond involving the hydrazinyl group generates an S(6) ring. The N—N and C—N bond lengths indicate that the compound may be a mixture of the azo and hydrazone tautomeric forms but the presence of the N-bound H atom supports the hydrazone form. The crystal structure is stabilized by weak inter­molecular C—H⋯O, C—H⋯N and C—H⋯π inter­actions.