Preparation | The product was synthesized by reacting p-ethylpropiophenone (2) with guanidine hydrochloride through Mannieh. The route is shown in Figure 1:
Figure 1 shows the reaction route for the synthesis of eperisone hydrochloride resolve resolution: 1. Synthesis of p-ethylpropiophenone (2) Propylene chloride (100 g, 1.08 mol) was charged, and the treated reaction liquid was recovered to recover petroleum ether and excess ethylbenzene, and then distilled under reduced pressure to collect bP112-114 ° C / 1.33 kPa fraction to obtain 2.
2. Synthesis of acetaminophen hydrochloride (1) Take a new distillation and stir (20.2g, 0.24 mol), add absolute ethanol (20 ml), add concentrated hydrochloric acid to pH 4-5 at low temperature, distill off ethanol under reduced pressure and then add absolute ethanol (50 ml). p-Ethylpropiophenone (32.4g, 0.2mol), 36% formaldehyde solution (42.0g, 0.5mol) and concentrated hydrochloric acid (1ml), stirred under reflux for 8h, the solvent was evaporated, the residue was dissolved in 10% sodium hydroxide, ether The extract is washed with water, dried, and hydrogen chloride is introduced into the ice water bath to pH 2-3. The resulting solid was filtered off and recrystallized from ethanol-hexane to give 1 colorless crystal. |