5-Carboxypyridazin-3(2H)-one

1,6-Dihydro-6-oxopyridazine-4-carboxylic acid

1,6-dihydro-6-oxo-4-pyridazinecarboxylic acid

3-oxo-2,3-dihydropyridazine-5-carboxylic acid

1,6-Dihydro-6-oxo-pyridazin-4-carboxylic acid

4-Pyridazinecarboxylic acid, 1,6-dihydro-6-oxo-