Methyl 3-(difluoromethyl)-5-nitro-2-(trifluoromethoxy)pyridine-4-acetate
Methyl 3-(difluoromethyl)-5-nitro-6-(trifluoromethoxy)pyridine-2-acetate
Methyl 2-(difluoromethyl)-6-nitro-3-(trifluoromethoxy)pyridine-4-acetate
Methyl 3-(difluoromethyl)-4-nitro-2-(trifluoromethoxy)pyridine-6-acetate