2-Amino-5-(difluoromethyl)-3-hydroxypyridine-4-carboxylic acid
6-Amino-4-(difluoromethyl)-2-hydroxypyridine-3-carboxylic acid
2-Amino-4-(difluoromethyl)-6-hydroxypyridine-3-carboxylic acid
6-Amino-4-(difluoromethyl)-3-hydroxypyridine-2-carboxylic acid