4-Pyridazinecarboxylic acid, 1,6-dihydro-6-oxo-, methyl ester
4-Pyridazinecarboxylic acid, 6-hydroxy-, methyl ester
Methyl 1,6-dihydro-6-oxo-4-pyridazinecarboxylate
Methyl 6-oxo-1,6-dihydropyridazine-4-carboxylate
1,6-Dihydro-6-oxo-4-Pyridazinecarboxylic acid methyl ester