A mixture of 4-bromo-2-ethyl-N-((1-methyl-1H-indazol-5-yl)methyl)benzenesulfonamide (prepared in step-1 of Example 4, 263 mg, 0.64 mmol), palladium(II) acetate (43 mg, 0.19 mmol), 1,3-bis(diphenylphosphino)propane (80 mg, 0.19 mmol) and triethylamine (130 mg, 1.29 mmol) in the mixture of DMF (7 mL)-MeOH (2.8 mL) was stirred at 100° C. for 1 day under carbon monooxide atmosphere. Then, to the mixture was added palladium(II) acetate (43 mg, 0.19 mmol), 1,3-bis(diphenylphosphino)propane (80 mg, 0.19 mmol). The mixture was stirred at 100° C. for 2 hrs under carbon monooxide atmosphere. The mixture was poured into EtOAc-hexane (2:1) and washed with 2 M aqueous HCl and H2O. The organic layer was dried over Na2SO4, filtered and concentrated. The residual solid was purified by silicagel column chromatography (0-40% EtOAc in hexane) to give titled compound (160 mg, 64%) as a white solid.
