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