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