3,3-Bis(hydroxyaryl)-2-benzofuran-1(3
H)-ones generally derived from the condensation of phthalic anhydride with phenols. E.g. phenolphthalein.
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See: xanthenes
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1359 (https://doi.org/10.1351/pac199567081307)