Ethyl 2-bromo-4-cyano-5-(difluoromethyl)pyridine-3-carboxylate
Ethyl 2-bromo-4-cyano-3-(difluoromethyl)pyridine-5-carboxylate
Ethyl 2-bromo-3-cyano-6-(difluoromethyl)pyridine-4-carboxylate
Ethyl 2-bromo-3-cyano-5-(difluoromethyl)pyridine-4-carboxylate