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