Ethyl 3-(difluoromethyl)-6-nitro-2-(trifluoromethyl)pyridine-5-acetate
Ethyl 3-(difluoromethyl)-6-nitro-4-(trifluoromethyl)pyridine-2-acetate
Ethyl 5-(difluoromethyl)-2-nitro-4-(trifluoromethyl)pyridine-3-acetate
Ethyl 5-(difluoromethyl)-2-nitro-3-(trifluoromethyl)pyridine-6-acetate