3',6'-Dihydroxy-3-oxospiro(isobenzofuran-1(3H),9'-(9H)xanthene)-ar-carboxylic acid 72088-94-9 80537-70-8 94595-55-8 EINECS 276-331-1 Spiro(isobenzofuran-1(3H),9'-(9H)xanthene)-ar-carboxylic acid, 3',6'-dihydroxy-3-oxo-