Hydrochloric Acid → 3-(Dimethylamino)-1-(3,4,5-trimethoxyphenyl)propan-1-one

Participants

Reaction Conditions

Reaction Steps

Concentrated hydrochloric acid (1 mL) was added to a stirred mixture of 3,4,5-trimethoxyacetophenone (210 g, 1 mol), dimethylamine hydrochloride (81 g, 1 mol) and paraformaldehyde (45 g, 1.5 mol) in ethanol (300 mL). The reaction mixture was heated under reflux for 1 hour. Another portion of paraformaldehyde (30 g, 1 mol) was added and the heating was continued for another 2 hours. The warm reaction mixture was poured with vigorous stirring into acetone (2.4 L). The slurry was heated at 60° C. for 15 minutes, cooled, and filtered. The solid was washed with acetone and dried to provide the hydrochloride salt of 3-(N,N-dimethylamino)-1-(3,4,5-trimethoxyphenyl)propan-1-one (196 g, 65%): R.function.0.05 (SiO2 ; hexane-ethyl acetate, 2:1; v/v); mp 175° C. A mixture of the above hydrochloride (147.5 g, 0.48 mol) in 1N NaOH (750 mL) was shaken with ethyl acetate (4×100 mL). The combined organic extracts were washed with brine, dried, and evaporated in vacuo to give 3-(N,N-dimethylamino)-1-(3,4,5-trimethoxyphenyl)propan-1 one mp 45°-47° C.

Provenance & Evidence