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