Isoprene → 1-(2,2,4-Trimethyl-3-cyclohexen-1-yl)ethan-1-one

Participants

Reaction Steps

Mesityl oxide (441 g) is added at 12°-16° C. to a stirred suspension of aluminum chloride (63 g) in toluene (2100 ml). A solution of isoprene (1224 g) in toluene (1800 ml) is then added over a period of 1.5 hr. at 15°-20° C. After approximately 48 hr. at 15°-25° C., the reaction mixture is washed successively with 10% hydrochloric acid sollution, water, 10% sodium bicarbonate solution, and water. The washed material is distilled rapidly at 3 mm Hg using a short column to give 626 g of crude product. Fractionation of 548 g of this material through a 12"×1", Goodloe packed column gives 478 g of 4-acetyl-1,3,3-trimethyl-1-cyclohexene containing a small amount of 1,8-p-menthadiene. The structure is confirmed by NMR (1H and 13C).

Provenance & Evidence