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