171408-84-7

white powder

General procedure for the synthesis of 2,7-dibromo-9,9'-spirobifluorene from the compound (CAS: 171408-85-8): to a toluene solution containing 180 g of 9-(2-biphenylyl)-2,7-dibromo-9-fluorenol (the product of Example 3), the reaction was initiated by the slow addition of 18.0 g (0.180 mol, 2.00 M) of concentrated sulfuric acid. The reaction mixture was stirred at room temperature for 2 hours. Upon completion of the reaction, aqueous caustic soda solution was added dropwise to the mixture until neutral, followed by the addition of toluene to promote crystallization. The precipitated white crystals were collected by filtration and washed with an appropriate amount of toluene and dried to afford 35.9 g of 2,7-dibromo-9,9'-spirobifluorene (yield: 80%, based on Example 3 the total yield was 72%, HPLC purity ≥95%).

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