To a solution of 2-(2,4-Dichloro-benzoyl)-6-m-tolyl-benzofuran-3-carboxylic acid from step 6 (61.2 mg, 0.14 mmol, 1 eq) in anhydrous THF (3 mL) solution were added EDC (60.0 mg, 0.31 mmol, 2.2 eq) and HOBt (50.0 mg, 0.37 mmol, 2.6 eq). The reaction mixture was stirred at rt for 1 h. A 30% aq. NH4OH solution (0.5 mL) was added to the reaction mixture and stirring was continued for 15 h. The reaction mixture was poured into EtOAc (10 mL). The organic layer were washed with 1N NaOH (5 mL), 1N HCl (5 mL), brine (5 mL). The organic layer was dried over Na2SO4, filtrated, and evaporated in vacuo. The residue was purified by pre-TLC (10% Acetone/DCM) to afford an yellow solid (46.2 mg, 78%) as product. 1H-NMR (CDCl3): δ 9.39 (broad, NH, 1H), 8.58 (d, J=8.3 Hz, 1H), 7.68 (dd, J=1.5, 8.3 Hz, 1H), 7.63 (s, 1H), 7.51 (d, J=1.5 Hz, 1H), 7.48 (d, J=8.3 Hz, 1H), 7.43-7.40 (m, 3H), 7.32 (t, 1H), 7.18 (d, J=8.3 Hz, 1H), 6.01 (broad, NH, 1H), 2.42 (s, 3H); LC-MS (MH+=424/426).
