2-(3-Methyl-2-oxo-1,2-dihydroquinoxalin-1-yl)acetic acid dihydrate

In the title compound, C11H10N2O3·2H2O, the constituent atoms of the dihydroquinoxaline moiety deviate from the mean plane of the unit by +0.0572 (8) to −0.0874 (8) Å while the acetic acid substituent is nearly orthogonal to this plane. The crystal packing consists of corrugated layers constructed by O—H...O, O—H...N and C—H...O hydrogen bonds, which also involve the lattice water molecules. O—H...O hydrogen bonds and π–π stacking interactions hold these layers together.