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