Hydrochloric Acid → 1-Methyl-3-phenylpiperazine

Beteiligte Stoffe

Reaktionsschritte

NaBH4 (75.4 g, 1.99 mol) and compound (I) obtained in example 3 (80 g, 0.332 mol) were placed in a 2 L cylindrical reactor. The mixture was cooled to 0°-50° C. with an ice water bath and 1,2-dimethoxyethane (640 mL) was loaded, with an exothermic reaction of approximately 8° C. being observed and hardly any gas release. The suspension was cooled to 0°-5° C. and a solution of 1,2-dimethoxyethane/HCI 6.5 N (297 mL, 1.93 mol) was slowly added without exceeding 20° C., with an exothermic reaction being observed and an intense gas release. The mixture was heated to 42°±30° C. for 6 hours, it was cooled to 10°-15° C. and an aqueous solution of HCl 6 N was added to pH 1 (305 mL), with an exothermic reaction being observed and an intense gas release. The resulting whitish suspension was stirred at 20°±2° C. for at least 1 hour, it was cooled to 10°-15° C.; alkalinised with an aqueous solution of NaOH 50% (p/p) to pH 12-14 (170 mL) and extracted with dichloromethane (3×250 mL). The accumulated organic phases were evaporated at reduced pressure, giving a yellowish liquid residue corresponding to the title product (56.33 g, 96.15%).

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