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