β-Dimethylaminopropiophenone hydrochloride could be produced through the following synthetic route.

In a 500-ml. round-bottomed flask attached to a reflux condenser are placed 60 g. (58.5 ml., 0.5 mole) of acetophenone, 52.7 g. (0.65 mole) of dimethylamine hydrochloride, and 19.8 g. (0.22 mole) of paraformaldehyde. After the addition of 1 ml. of concentrated hydrochloric acid (sp. gr. 1.19) in 80 ml. of 95% ethanol, the mixture is refluxed on a steam bath for 2 hours. The yellowish solution is filtered, if it is not clear, and is transferred to a 1-l. wide-mouthed Erlenmeyer flask. While still warm, it is diluted by the addition of 400 ml. of acetone, allowed to cool slowly to room temperature, and then chilled overnight in the refrigerator. The large crystals are filtered and washed with 25 ml. of acetone. After it has been dried for 2.5 hours at 40–50°, this crude product weighs 72–77 g. (68–72%) and melts at 138–141°; it is suitable for many reactions.

It may be recrystallized by dissolving it in 85–90 ml. of hot 95% ethanol and slowly adding 450 ml. of acetone to the solution. The recovery is about 90%. The purified material, dried at 70°, melts at 155–156°.