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

Participants

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 to a boiling suspension of 10.0 g (29.6 mmol) of 2,7-dibromo-9-fluorenone in 100 ml of dry diethyl ether with stirring (in an ultrasound bath) over the course of 2 h. When addition is complete, the mixture is boiled for a further 3 hours. After cooling overnight, the precipitate which had 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 iced water. After 1 h, the 9-(2-biphenylyl)-2,7-dibromo-9-fluorenol which formed was filtered off with suction, washed with water and was sucked dry. For the ring-closure reaction, the dried fluorenol was boiled for 6 hours in 100 ml of glacial acetic acid, after the additon of 3 drops of conc. HCl. The mixture was left to crystallize overnight, and the product which formed was filtered off with suction and washed with glacial acetic acid and water.

Provenance & Evidence