Cyclopropylamine → 2-amino-3-bromo-N-cyclopropylbenzamide

Participants

Reaction Steps

To a heterogenous mixture of 2-amino-3-bromobenzoic acid (Sigma-Aldrich; 8.00 g, 37.0 mmol) in EtOAc (80 mL) at 0° C. was added 1-propanephosphonic acid cyclic anhydride (T3P) (Alfa-Aesar; 50 wt. % solution in EtOAc, 24.00 mL, 40.7 mmol) followed by cyclopropylamine (2.57 mL, 37.0 mmol). The ice bath was removed and the reaction was stirred at RT for 1 h. Saturated NaHCO3 (aq.) was added and the mixture was stirred for 5 minutes. The layers were separated and the organic layer was washed with saturated NaHCO3 (aq.) and brine. The aqueous layer was extracted with EtOAc (3×). The combined organic layers were dried over anhydrous Na2SO4, filtered and concentrated to afford 2-amino-3-bromo-N-cyclopropylbenzamide (723a; 6.00 g, 23.52 mmol, 64% yield) as a white solid. 1H NMR (400 MHz, CDCl3) δ ppm 7.50 (dd, J=7.82, 1.37 Hz, 1H), 7.20 (dd, J=7.92, 1.27 Hz, 1H), 6.50 (t, J=7.82 Hz, 1H), 6.13 (br. s., 2H), 2.85 (tq, J=7.02, 3.54 Hz, 1H), 0.83-0.91 (m, 2H), 0.57-0.64 (m, 2H). m/z (ES, +ve) 255.1, 257.0 (M+H)+.

Provenance & Evidence