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