2-(6-Hydroxy-3-oxo-3H-xanthen-9-yl)benzoic acid 518-45-6 9-(o-Carboxyphenyl)-6-hydroxy-3-isoxanthenone Benzoic acid, 2-(6-hydroxy-3-oxo-3H-xanthen-9-yl)- Benzoic acid, o-(6-hydroxy-3-oxo-3H-xanthen-9-yl)-