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