Hydrogen Bromide → 2,4,7-trimethyl-1-indanone

Participants

Reaction Conditions

Reaction Steps

6.66 g of p-xylene (62.10 mmol) were added at room temperature to a suspension of 10.51 g of AlCl3 (78.0 mmol) in 40 ml of chlorobenzene under nitrogen; the so obtained yellow suspension was cooled to 0° C. and 6.50 ml of 2-bromoisobutyrylbromide (52.6 mmol, AlCl3/p-xylene/2-bromoisobutyrylbromide=1.5/1.2/1.0) were added dropwise in about 2 min. The flask is connected to a water trap in which the produced HBr gas is neutralized with a base. At the end of the addition, the solution was allowed to reach ambient temperature. The so obtained red solution was stirred for 2 h. The reaction mixture was transferred into a flask containing 30 g of ice and 10 ml of 37% HCl, stirred for 15 min, then the organic layer was separated, and the aqueous layer washed with Et2O (2×100 ml). The combined organic layers were washed with a saturated solution of NaHCO3 in water, then with H2O. The solution was dried over Na2SO4 and then all volatiles were removed in vacuo to leave a slightly yellow oil (8.95 g, yield 98%).

Provenance & Evidence