Potassium Carbonate → HCID 67666471, compound

Participants

Reaction Conditions

Reaction Steps

2-[4-(Acetylamino)phenyl]ethyl bromide (2.6 g, 10.7 mmol) was added to a mixture of N-tert-butyloxycarbonyl piperazine (2.0 g, 10.7 mmol) and K2CO3 (3.0 g, 21.7 mmol), in IPA (100 ml), and heated at 100° C. for 16 h. The mixture was filtered and the filtrate evaporated under vacuum. The residue was taken up into ethyl acetate and washed with H2O . The aqueous phase was extracted with EtOAc and the combined extracts dried (Na2SO4 /MgSO4) and evaporated. The crude product was chromatographed on silica gel eluting with ethyl acetate to give 1-tert-butyloxycarbonyl-4-[2-(4-(acetylamino)phenyl)ethyl]piperazine (1.8 g, 49%) which was shown to be pure by 1H NMR. A solution of the preceding N-Boc piperazine (1.8 g, 5.19 mmol) in 99% formic acid (30 ml) was stirred at room temperature for 16 h. The solvent was removed under vacuum and the product chromatographed on silica gel eluting with CH2Cl2 / MeOH/NH3 (50:8:1) to give the title-piperazine (1.3 g, 100%) δ(250 MHz, D6 -DMSO) 2.01 (3H, s, Me), 2.26-2.72 (12H, m, 6 of CH2), 7.12 (2H, d, J=8.5 Hz, Ar-H), 7.46 (2H, d, J=8.5 Hz, Ar-H), 9.85 (1H, s, NH).

Provenance & Evidence