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