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