3-Cyano-2-hydroxy-4-(trifluoromethoxy)pyridine-6-carboxylic acid
2-Cyano-4-hydroxy-6-(trifluoromethoxy)pyridine-3-carboxylic acid
2-Cyano-4-hydroxy-3-(trifluoromethoxy)pyridine-6-carboxylic acid
2-Cyano-3-hydroxy-6-(trifluoromethoxy)pyridine-4-carboxylic acid