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