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