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