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