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

Beteiligte Stoffe

Reaktionsschritte

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 to a boiling suspension of 10.0 g (29.6 mmol) of 2,7-dibromo-9-fluorenone in 100 ml of dry diethyl ether in the course of 2 hours, while stirring (in an ultrasonic bath). When the addition had ended, the mixture was boiled for a further 3 hours. After cooling overnight, the precipitate which had separated out 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 cyclization reaction, the dried fluorenol was boiled in 100 ml of glacial acetic acid, after addition of 3 drops of concentrated hydrochloric acid, for 6 hours. The mixture was left to crystallize overnight and the product formed was filtered off with suction and washed with glacial acetic acid and water.

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