Methyl 3-(difluoromethyl)-5-nitro-4-(trifluoromethyl)pyridine-2-carboxylate
Methyl 3-(difluoromethyl)-5-nitro-2-(trifluoromethyl)pyridine-4-carboxylate
Methyl 6-(difluoromethyl)-4-nitro-3-(trifluoromethyl)pyridine-2-carboxylate
Methyl 2-(difluoromethyl)-4-nitro-3-(trifluoromethyl)pyridine-6-carboxylate