Ethyl 3-amino-6-(difluoromethyl)-2-hydroxypyridine-5-carboxylate
Ethyl 3-amino-6-(difluoromethyl)-4-hydroxypyridine-2-carboxylate
Ethyl 5-amino-2-(difluoromethyl)-4-hydroxypyridine-3-carboxylate
Ethyl 5-amino-2-(difluoromethyl)-3-hydroxypyridine-6-carboxylate