3-Pyridinecarboxylic acid, 6-[(carboxymethyl)thio]-5-cyano-1,2-dihydro-2-oxo-, 3-ethyl ester
3-Ethyl 6-[(carboxymethyl)thio]-5-cyano-1,2-dihydro-2-oxo-3-pyridinecarboxylate
2-[[3-Cyano-5-(ethoxycarbonyl)-6-oxo-1,6-dihydropyridin-2-yl]sulfanyl]acetic acid