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