1,2-Dichloroethane → 5,6,7,8-Tetrahydro-3-hydroxy-5,5,8,8-tetramethyl-2-naphthyl methyl ketone

Participants

Reaction Conditions

Reaction Steps

The hydroxynaphthalene (19.1 g, 93.6 mmol) was treated dropwise with acetyl chloride (7.7 g, 98.2 mmol) in 1,2-dichloroethane (250 ml) at 0° C. After completion of the addition, aluminum chloride (10 g, 75.2 mmol) was added in portions over 5 min. The mixture was heated at reflux for 10 h, then stirred at 25° C. for 8 h. GC analysis indicated the desired keto-phenol was present in 98.6% purity. The reaction mixture was poured onto ice water and aqueous work-up (EtOAc extraction) gave a brown-black solid, which was dissolved in hot methanol, filtered, and concentrated to give a brown viscous semi-solid. Flash chromatography (15% EtOAc/hexane) gave 1-(3-hydroxy-5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-naphthalen-2-yl)ethanone as a light yellow solid. Recrystallization from hexane afforded the product as white crystals 15.2 g (66%): 1H NMR (400 MHz, CDCl3) δ 7.63 (s, 1H, ArH), 6.9 (s, 1H, ArH), 2.61 (s, 3H, CH3), 1.67 (s, 4H, 2CH2), 1.29 (s, 6H, 2CH3), 1.27 (s, 6H, 2CH3).

Provenance & Evidence