Hydrogen Bromide → HCID 20426625, compound

Participants

Reaction Steps

141.7 g (0.478 mole) of the 2,3-dihydro-4,5-dimethoxy-2,7-dimethyl-2-phenyl-1H-inden-1-one obtained according to Example 2(d) are boiled under slight reflux for 45 minutes with a mixture of 275 ml of aqueous 48% strength hydrobromic acid, 475 ml of glacial acetic acid and 72 ml of 33% strength hydrogen bromide in glacial acetic acid and then the reaction mixture is poured into 3000 ml of a mixture of ice and water. The product so obtained is extracted twice with ether and the ethereal phases are washed once with water, once with dilute sodium bicarbonate solution, and twice with water again. The ethereal phases are dried over sodium sulphate, filtered, and concentrated to dryness by evaporation in vacuo in a rotary evaporator. The crude residue of 135 g of brown crystals is dissolved warm in 250 ml of ethyl acetate and filtered. Subsequently, 500 ml of petroleum ether having a boiling range of 40°-60° are added. On leaving to stand, the product crystallises out and can be filtered and dried. In this manner 2,3-dihydro-2,7-dimethyl-4-hydroxy-5-methoxy-2-phenyl-1H-inden-1-one having a melting point of 136°-139° is obtained.

Provenance & Evidence