Methyl iodide → (+/-)-4-Dimethylamino-2-methyl-4-phenylcyclohexanone

Participants

Reaction Conditions

Reaction Steps

Diisopropylamine (2.1 ml, 15 mmol) was provided in dry THF in argon and mixed with n-butyl lithium in hexane (2.5M, 6 ml, 15 mmol) at 30° C. The reaction mixture was cooled to −78° C. 4-(dimethylamino)-4-phenylcyclohexanone (2.17 g, 10 mmol), dissolved in 10 ml of dry THF, was added in drops to this solution within 10 min. The batch was stirred for 30 min at −78° C. and then mixed with methyl iodide (1.86 ml, 30 mmol). It was heated to RT and stirred for a further 18 h. The solvent was removed at the rotary evaporator and the residue taken up in DCM. Extraction was conducted with 1N HCl (3×30 ml). The aqueous phase was basified with 5N NaOH (20 ml) and extracted with DCM (3×30 ml). The combined organic phases were washed with H2O (2×10 ml) and dried over Na2SO4. The semisolid residue (1.2 g) obtained after removal of the solvent was recrystallised from ethyl acetate (1 ml).

Provenance & Evidence