The product was synthesized by reacting p-ethylphenylacetone (2) with guanethidine hydrochloride via the Mannieh reaction, as shown in Figure 1:
Figure 1 shows the reaction route for the synthesis of ethylperisone hydrochloride
Synthesis method: 1. Synthesis of p-ethylphenylacetone (2)
Propyl chloride (100g, 1.08 mol) was added. After treatment, the reaction solution was distilled under reduced pressure after recovering petroleum ether and excess ethylbenzene. The fraction at bP112-114 ℃/1.33kPa was collected to obtain 2.
2. Synthesis of ethylparaben (1)
Take freshly distilled ethylparaben (20.2 g, 0.24 mol), add anhydrous ethanol (20 ml), add concentrated hydrochloric acid dropwise at low temperature to pH 4-5, evaporate the ethanol under reduced pressure, then add anhydrous ethanol (50 ml), p-ethyl acetone (32.4 g, 0.2 mol), 36% formaldehyde solution (42.0 g, 0.5 mol) and concentrated hydrochloric acid (1 ml), stir and reflux for 8 h, evaporate the solvent, dissolve the residue in 10% sodium hydroxide solution, extract with ether, wash the extract with water, dry, and pass hydrogen chloride through in an ice-water bath to pH 2-3. Filter out the generated solid, recrystallize with ethanol-acetone to obtain 1 colorless crystal.
