Hydrochloric Acid → 1-Methyl-3-phenylpiperazine

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Reaction Steps

Compound (I) of the previous example (0.5 g, 2.077 mmol) and tetrahydrofurane (5 mL) were placed in a 25 mL flask, and for approximately 10 minutes the BH3.THF complex 1 M (10.4 mL, 10.386 mmol) was added to the white suspension. The resulting colourless solution was heated to reflux temperature for 6.5 hours, it was cooled to 19°±1° C. and an aqueous solution of HCl 6 N (1.82 mL) was added slowly. The mixture was distilled at reduced pressure to remove the tetrahydrofurane. Ethyl acetate (5 mL) was added and was extracted with an aqueous solution of HCl 2 N (3×5 mL). The accumulated acidic phases were alkalinised with an aqueous solution of NaOH 50% (p/p) to pH 12-13 (1.1 mL), saturated with NaCl (6.25 g) and were extracted with ethyl acetate (3×5 mL). The accumulated organic phases were dried with anhydrous Na2SO4, they were filtered and evaporated at reduced pressure, giving a yellowish liquid residue which corresponded to the title product (0.3 g, 81.97%).

Provenance & Evidence