Trifluoroacetic acid → Tert-butyl 4-[2-(aminomethyl)phenyl]piperazine-1-carboxylate

Participants

Reaction Steps

To a solution of (2-cyano-phenyl)-piperazine (2.4 g, 12.78 mmol) in THF and H2O (25 mL, 1:1) was added K2CO3 (3.9 g, 28.12 mmol). The solution was allowed to stir for about 10 minutes at r.t. Boc-anhydride (3.1 g, 14.06 mmol) was then added and reaction was allowed to stir for 1 h. The reaction mixture was diluted with EtOAc (100 mL) and washed with sat. NaHCO3 (100 mL) and brine (100 mL). The organic phase was concentrated to dryness yielding 3.2 g of 1-Boc-4-(2-cyano-phenyl)-piperazine (88%). To a solution of sodium borohydride (2.1 g, 56.03 mmol) in THF (25 mL) at 0° C. was added TFA (4.3 mL, 56.03 mmol) dropwise. 1-Boc-4-(2-cyano-phenyl)-piperazine (3.2 g, 11.21 mmol) was then added slowly at r.t. The reaction was allowed to stir for about 12 hours at r.t. The reaction was quenched with H2O, diluted five-fold with EtOAc and washed with brine. The organic phase was concentrated to dryness yielding about 1.0 g of 1-Boc-4-(2-aminomethyl-phenyl)-piperazine (30%). MS (ESI+) 292.1 (M+1)

Provenance & Evidence