A solution of 3-(benzenesulfonyl-benzyl-amino)-benzoic acid (25 mg, 0.068 mmol), 6-amino-1H-indazole (18 mg, 0.136 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (15 mg, 0.075 mmol), mercaptobenzothiazole (2 mg, 0.007 mmol) and triethylamine (24 μl, 0.17 mmol) in dry acetonitrile (2 ml) were stirred at room temperature for 15 hrs. The reaction mixture was quenched with water (10 ml) and extracted with dichloromethane (3×7 ml). The organics were combined, dried (PTFE frit) and concentrated in vacuo. The crude residue was purified by preparative TLC (10% diethyl ether in dichloromethane) to afford the title compound as a brown solid (15 mg, 45%). HPLC retention time 5.80 min. Mass spectrum (ES+) m/z 483 (M+H).
