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