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