Ethyl 3-amino-2-(difluoromethyl)-5-methoxypyridine-4-carboxylate
Ethyl 4-amino-2-(difluoromethyl)-3-methoxypyridine-6-carboxylate
Ethyl 3-amino-5-(difluoromethyl)-6-methoxypyridine-2-carboxylate
Ethyl 2-amino-6-(difluoromethyl)-4-methoxypyridine-3-carboxylate