In a nitrogen atmosphere, concentrated sulfuric acid (0.2 mL) was added to a mixture of 4-hydroxybenzoic acid (13.0 g), 2,7-dihydroxy-9-methylfluorene (10.0 g), boric acid (0.3 g) and xylene (120 mL), and the mixture was heated under reflux for 6 hours while removing water. A solid matter thus deposited was collected by filtration under reduced pressure, and rinsed with toluene. The solid matter was recrystallized from a mixed solvent of ethanol (75 mL) and acetone (75 mL) to provide 2,7-bis(4-hydroxybenzoyloxy)-9-methylfluorene (compound [H1]) (14.9 g) in the form of pale rose crystals.
