To a solution of 5-(3-iodo-1H-indol-5-yl)-1,2,4-oxadiazol-3-amine (0.3 g, 0.92 mmol) and 2-isopropoxy-6-(tributylstannyl)pyridine (0.471 g, 1.1 mmol) in DMF (10 mL) was bubbled with N2 gas for 15 min. To the mixture was added CuI (0.140 g, 0.73 mmol) and Pd(PPh3)4 (0.100 g, 0.092 mmol) and N2 gas was bubbled for another 15 min. The reaction was heated at 90° C. for 1 h. The reaction mixture was cooled to RT, and quenched with water (100 mL) and extracted in EtOAc (2×100 mL). The organic layer was dried over anhydrous Na2SO4 and concentrated. The residue was purified with preparative HPLC (eluent: 30-70% MeCN in water with 0.01% TFA) to afford 5-(3-(6-isopropoxypyridin-2-yl)-1H-indol-5-yl)-1,2,4-oxadiazol-3-amine (0.01 g, 7%) as a white solid. MS (ESI, pos. ion) m/z: 336.2 (M+1); 1H-NMR (400 MHz, CD3OD): δ 9.36 (s, 1H), 7.99 (s, 1H), 7.89 (d, J=8.4 Hz, 1H), 7.64 (m, 2H), 7.37 (d, J=7.6 Hz, 1H), 6.52 (d, J=8.4 Hz, 1H), 5.65 (m, 1H), 1.51 (d, J=6.0 Hz, 6H).
