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