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

Participants

Reaction Steps

1-Propanephosphonic acid cyclic anhydride (10.94 mmol, 6.51 mL, 6.96 g, 50% solution in ethyl acetate) was added to a stirred solution of 4-aminobenzoic acid (7.29 mmol, 1 g), tert-butyl piperazine-1-carboxylate (7.29 mmol, 1.358 g) and triethylamine (14.58 mmol, 1.969 mL, 1.473 g) in dichloromethane (30 mL). The reaction mixture was stirred for 5 hours, then was washed with sodium bicarbonate and filtered through silica, eluting with ethyl acetate. Evaporation of solvent afforded the title compound (1.53 g). 1H NMR (MeOD, 400 MHz): δ 1.4 (9H, s), 3.4 (4H, m), 3.6 (4H, m), 6.7 (1H, m), 7.2 (2H, m)

Provenance & Evidence