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