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