ChEBI: Uracil-5-carboxylic acid is a pyrimidinemonocarboxylic acid that is uracil carrying a carboxy group at position 5. It is functionally related to a uracil. It is a conjugate acid of a uracil-5-carboxylate. It is a tautomer of a 2,4-dihydroxypyrimidine-5-carboxylic acid.