5-Hydroxy-4-nitro-2-(trifluoromethoxy)pyridine-3-carboxaldehyde
4-Hydroxy-5-nitro-3-(trifluoromethoxy)pyridine-2-carboxaldehyde
3-Hydroxy-4-nitro-5-(trifluoromethoxy)pyridine-2-carboxaldehyde
4-Hydroxy-3-nitro-2-(trifluoromethoxy)pyridine-5-carboxaldehyde