Redetermination of 6-amino-5-formyl-1,3-dimethyl­uracil monohydrate at 120 K: a polarized mol­ecular structure and two inter­woven hydrogen-bonded frameworks

The title compound [systematic name: 6-amino-5-formyl-1,3-dimethylpyrimidine-2,4(1H,3H)-dione monohydrate], C₇H₉N₃O₃·H₂O, has been reexamined at 120 K. The improved precision of the intra­molecular dimensions provides evidence for a polarized mol­ecular–electronic structure, and the mol­ecular components are linked by one N—H...O and two O—H...O hydrogen bonds into two inter­woven three-dimensional frameworks, which are weakly linked by the longer component of a three-centre N—H...(O)₂ hydrogen bond.