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