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