Acetyl chloride → 3-(Dimethylamino)-3'-methoxypropiophenone

Participants

Reaction Steps

The Eschenmoser salt was produced by reacting 232 g (2.27 mol, 1 equivalent) tetramethyl diaminomethane with 187 g (2.14 mol, 0.95 equivalent) acetyl chloride in 1200 ml acetonitrile. 328 g (2.17 mol, 0.96 equivalent) 3-methoxyacetophenone were then added within 115 minutes at a temperature of from +3° C. to +11° C. and then stirred at from +20° C. to +25° C. for 20 to 21 hours. The resulting hydrochloride salt of the 3-dimethylamino-1-(3-methoxyphenyl)-propan-1-one (II) was filtered out. The residue was suspended in 1600 ml water and 190 ml sodium hydroxide solution (36% by weight) (pH 11-12) and extracted with 1000 ml ethyl acetate. The organic phase was separated off and dried over 50 g sodium sulfate. Once the organic solvent had been evaporated, the free base of the 3-dimethylamino-1-(3-methoxyphenyl)-propan-1-one (II) was obtained as a colorless oil (93% yield, 96% purity ascertained by HPLC).

Provenance & Evidence