ethyl 4-chloropyriMidine-2-carboxylate

Ethyl 6-chloropyridazine-3-carboxylate

Ethyl 6-chloro-3-pyridazinecarboxylate

6-Chloro-pyridazine-3-carboxylic acid ethyl ester

3-Pyridazinecarboxylic acid, 6-chloro-, ethyl ester