6-(Difluoromethyl)-4-nitro-2-(trifluoromethoxy)pyridine-3-carboxylic acid
 
2-(Difluoromethyl)-4-nitro-5-(trifluoromethoxy)pyridine-3-carboxylic acid
 
Ethyl 4-methyl-6-nitro-2-(trifluoromethoxy)pyridine-3-acetate
 
2-(Difluoromethyl)-3-nitro-6-(trifluoromethoxy)pyridine-5-carboxylic acid