474918-32-6

off-white powder

10 g (30 mmol) of 2-bromo-9-phenyl-9H-fluoren-9-ol was dissolved in 60 ml of benzene, and 2.4 ml (45 mmol) of concentrated sulfuric acid diluted with a small amount of benzene was added to the solution. The mixture was stirred for 5 hours at 80° C, and after evaporating the benzene, 1 N sodium hydroxide solution was added to the remaining solution to a pH of around 7. The mixture was extracted 3 times with ethyl acetate (40 ml). The collected organic layer was dried with magnesium sulfate, and the residue obtained by evaporating the solvent was separated and purified by silica gel column chromatography. 6 g of Intermediate N (yield: 50%).