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

Beteiligte Stoffe

Reaktionsschritte

A Grignard reagent prepared from 0.97 g (40 mmol) of magnesium turnings and 9.32 g (6.8 ml, 40 mmol) of 2-bromobiphenyl in 50 ml of dry diethyl ether was added dropwise to a boiling solution of 13 g (40 mmol) of 2,7-dicarbethoxy-9-fluorenone in 100 ml of dry diethyl ether over the course of 2 h. When 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 was filtered off with suction and 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-dicarbethoxy-9-fluorenol which had formed was filtered off with suction, washed with water and sucked dry. For the ring-closure reaction, the dried fluorenol was boiled for 6 hours in 100 ml of glacial acetic acid, following the addition of 3 drops of conc. HCl. The mixture was left to crystallize overnight, and the product which had formed was filtered off with suction and washed with glacial acetic acid and water.

Herkunft & Nachweise