3-Hydroxy-6-methoxy-4-nitro-2-(trifluoromethoxy)pyridine
5-(Difluoromethyl)-4-hydroxy-2-nitro-3-(trifluoromethoxy)pyridine
3-(Difluoromethyl)-4-hydroxy-5-nitro-2-(trifluoromethoxy)pyridine
3-(Difluoromethyl)-2-hydroxy-5-nitro-4-(trifluoromethoxy)pyridine