3-(Difluoromethyl)-5-nitro-2-(trifluoromethoxy)pyridine-6-acetic acid
4-(Difluoromethyl)-3-nitro-5-(trifluoromethoxy)pyridine-2-acetic acid
4-(Difluoromethyl)-6-nitro-2-(trifluoromethoxy)pyridine-3-acetic acid
4-(Difluoromethyl)-2-nitro-5-(trifluoromethoxy)pyridine-3-acetic acid