2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid 4-pyrimidinecarboxylic acid, 1,2,3,6-tetrahydro-2,6-dioxo- InChI=1/C5H4N2O4/c8-3-1-2(4(9)10)6-5(11)7-3/h1H,(H,9,10)(H2,6,7,8,11