Methyl 3-amino-2-(difluoromethyl)-5-nitropyridine-6-carboxylate
Methyl 2-amino-6-(difluoromethyl)-3-nitropyridine-4-carboxylate
Methyl 6-amino-4-(difluoromethyl)-3-nitropyridine-2-carboxylate
4-Amino-5-(difluoromethyl)-3-nitropyridine-2-carboxylic acid