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