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