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