2-Bromobiphenyl → 9-(2-Biphenylyl)-2,7-dibromo-9-fluorenol

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Reaction Steps

 A Grignard reagent prepared from 0.72 g (30 mmol) of magnesium turnings and 5.1 ml (30 mmol) of 2-bromobiphenyl in 15 ml of diethyl ether was added dropwise while stirring (in an ultrasonic bath) to a boiling suspension of 10.0 g (29.6 mmol) of 2,7-dibromo-9-fluorenone in 100 ml of dry diethyl ether over a period of 2 hours. After addition was complete, the mixture was boiled for a further 3 hours. After cooling overnight, the precipitate formed was filtered off with suction and washed with cold ether. The magnesium complex which had been filtered off with suction was hydrolyzed in a solution of 15 g of ammonium chloride in 250 ml of ice water. After 1 hour, the 9-(2-biphenylyl)-2,7-dibromo-9-fluorenol formed was filtered off with suction, washed with water and sucked dry. For the ring closure reaction, the dried fluorenol was boiled in 100 ml of glacial acetic acid, after addition of 3 drops of concentrated HCl, for 6 hours. The mixture was allowed to crystallize overnight, the product formed was filtered off with suction and washed with glacial acetic acid and water.

Provenance & Evidence