A stirred solution of methyl N-{4-[(1H-benzimidazol-1-yl)methyl]benzoyl}-serinate (2.8 g, 7.93 mmol) in THF is treated with Burgess Reagent (2.26 g, 9.45 mmol) and activated 4 Å molecular sieves (1 g), stirred at 60° C. for 2 h, cooled to room temperature and concentrated under reduced pressure. A solution of the resultant residue (0.1 g, 0.29 mmol) in CH2Cl2 is cooled to 0° C., treated with bromo trichloromethane (0.06 g, 0.33 mmol) and DBU (0.05 g, 0.33 mmol), stirred at room temperature overnight and concentrated under reduced pressure. The resultant residue is purified by column chromatography (silica, CH3OH/CHCl3 0→5%) to give the title product in 52% yield, identified by NMR and mass spectral analyses. 1H NMR (400 MHz, DMSO-d6): 8.28 (s, 1H); 8.08 (d, J=8 Hz, 2H); 8.00 (m, 1H); 7.85 (d, J=8 Hz, 2H); 7.30 (m, 5H); 5.43 (s, 2H); 3.95 (s, 3H). LCMS (ESI+) 334 (MH+).
