Benzenesulfonyl chloride (65 μL, 0.48 mmol) and pyridine (289 μL, 3.58 mmol) were added to (5-amino-1-benzofuran-7-yl)pyridin-4-yl-amine (90 mg, 0.40 mmol; Intermediate 33) in DCM (2 mL). The mixture was heated at 40° C. for 10 min, shaken at room temperature for 1 h, and solvent was removed in vacuo. The residue was purified by preparative HPLC using acetonitrile-water gradients containing 0.1% trifluoroacetic acid. The obtained TFA salt was converted into the hydrochloride salt by treatment with 2 M HCl in ether to afford 78.7 mg (45%) of the title product. HPLC 100%, RT: 1.560 (System A; 10-97% MeCN over 3 min). 1H NMR (270 MHz, methanol-d4) δ ppm 6.91 (s, 1H) 7.04 (d, J=2.23 Hz, 2H) 7.36 (d, J=1.98 Hz, 1H) 7.51-7.65 (m, 3H) 7.74-7.77 (m, 2H) 8.03 (d, J=1.98 Hz, 1H) 8.32 (d, J=6.93 Hz, 2H) 10.43 (s, 1H) 10.84 (s, 1H). LC-MS 366 (M+H)+.
