2-Bromobenzoic acid → Tert-butyl 4-(2-bromobenzoyl)piperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

HOBt (4 g, 29.6 mmol) and DIEA (8.7 g, 67.7 mmol) were added to a stirred solution of 2-bromo benzoic acid (5.6 g, 28.3 mmol) in DMF (50 mL). The reaction mixture was cooled to 10° C. and EDCI.HCl (7.76 g, 40.48 mmol) followed by piperazine-1-carboxylic acid tert-butyl ester (5 g, 26.9 mmol) were added. Then reaction mixture was stirred at the room temperature overnight. Water was added and the product was extracted with ethyl acetate. The ethyl acetate was washed with brine solution, dried over Na2SO4, and removed under reduced pressure to afford 9 g (90%) of 4-(2-bromo-benzoyl)-piperazine-1-carboxylic acid tert-butyl ester. 1H NMR: (DMSO-d6): δ 7.58 (d, 1H), 7.38 (t, 1H), 7.29 (d, 1H), 7.24 (d, 1H), 3.85 (m, 1H), 3.7 (m, 1H), 3.55 (t, 2H), 3.5 (m, 1H), 3.3 (m, 3H), 3.15 (m, 1H), 1.45 (s, 9H).

Provenance & Evidence