Formic acid (ammonium salt) → (S)-2-(3-Phenyl-propyl)-piperazine

Participants

Reaction Steps

Combine (S)-1-benzyl-3-(3-phenyl-allyl)-piperazine (1.45 g, 5.0 mmol), 10% Pd/C (265 mg, 0.025 mmol) and ammonia formate (1.57 g, 25.0 mmol) in EtOH (90 mL) and heat to reflux for 3 hours, cool to room temperature, remove the catalyst by filtration. Concentrate the solvent to a residue, which 1H NMR shows that the carbon-carbon double bond has been reduced, but the benzyl group remains. Subject the residue to the reaction with 10% Pd(OH)2/C (350 mg, 0.5 mmol) in EtOH with a balloon of hydrogen under reflux conditions. After refluxing for 3 hours, cool the reaction to room temperature, remove the catalyst, concentrate to a residue, and purification by silica gel chromatography using 2N NH3 in MeOH and dichloromethane (5%–15%) to give the title compound (950 mg, 93%): mass spectrum (Electrospray): m/z=205.2 (M+1); 1H NMR (CDCl3): δ7.29–7.15 (m, 5H), 2.97–2.59 (m, 6H), 2.35 (t, 1H, J=9.8 Hz), 1.70–1.45 (m, 6H), 1.38–1.25 (m, 2H).

Provenance & Evidence