142975-81-3 2',7'-Dichloro-3',6'-dihydroxy-3-oxospiro(isobenzofuran-1(3H),9'-(9H)xanthene)-5-carboxylic acid 5'-Carboxyl-2',7'-dichlorodihydrofluorescein 5'-H2-Cdcf Spiro(isobenzofuran-1(3H),9'-(9H)xanthene)-5-carboxylic acid, 2',7'-dichloro-3',6'-dihydroxy-3-oxo-