Hydrochloric Acid → Tert-butyl 4-(4-aminobenzoyl)piperazine-1-carboxylate

Participants

Reaction Steps

To a solution of 4-aminobenzoic acid (0.411 g, 3.00 mmol) in DMF (5.0 mL) at room temperature was added EDCl.HCl (0.862 g, 4.50 mmol), HOBt (0.608 g, 4.50 mmol), Et3N (0.835 mL, 6.00 mmol) and N-Boc piperazine (0.671 g, 3.60 mmol). The resulting mixture was stirred at room temperature for 21 hours then 2 M aqueous NaOH was added to adjust the pH to >10. EtOAc was added then the layers separated and the organic layer dried over MgSO4. The volatiles were removed under reduced pressure and the residue was purified by silica gel chromatography (Biotage Isolera, 40 g SiO2 cartridge, 50-90% EtOAc in petroleum benzine 40-60° C.) to give the title compound A21 as a white solid (0.530 g, 56%); LCMS-A: rt 5.079 min; m/z 250.1 [(M-t-Bu)+H]+, 206.1 [(M-Boc)+H]+.

Provenance & Evidence