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