Ethyl 3-(difluoromethyl)-6-methoxy-2-nitropyridine-5-acetate
Methyl 4-(difluoromethyl)-2-methyl-3-nitropyridine-5-carboxylate
Ethyl 5-(difluoromethyl)-2-methoxy-4-nitropyridine-3-acetate
Methyl 3-(difluoromethyl)-5-methyl-6-nitropyridine-2-carboxylate