2-Hydroxy-5-nitro-4-(trifluoromethoxy)pyridine-3-carboxylic acid
6-Hydroxy-4-nitro-2-(trifluoromethoxy)pyridine-3-carboxylic acid
2-Hydroxy-4-nitro-5-(trifluoromethoxy)pyridine-3-carboxylic acid
2-Hydroxy-6-nitro-3-(trifluoromethoxy)pyridine-4-carboxylic acid