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