To a solution of 4-(benzyloxy)-1-(1H-indazol-5-yl)pyridine-2(1H)-one (200 mg, 0.63 mmol) in DMSO (5 mL) was added Cs2CO3 (1.03 g, 3.15 mmol) and (3-bromopropoxy)-tert-butyldimethylsilane (0.15 mL, 0.66 mmol). After stirring overnight at ambient temperature under argon, the reaction mixture was filtered through a layer of Celite and concentrated. Purification by flash column chromatography (silica gel, EtOAc/hexanes, 50:50) gave 4-(benzyloxy)-1-(1-(3-(tert-butyldimethylsilyloxy)propyl)-1H-indazol-5-yl)pyridin-2(1H)-one (90 mg, 29%). To a solution of 4-(benzyloxy)-1-(1-(3-(tert-butyldimethylsilyloxy)propyl)-1H-indazol-5-yl)pyridin-2(1H)-one in THF (3 mL) was added TBAF (0.75 mL, 0.75 mmol, 1.0 M). After the reaction was complete, the mixture was treated with H2O, extracted with CH2Cl2, and the combined organics were concentrated. Purification by flash column chromatography (silica gel, EtOAc/hexanes, 50:50) gave 4-(benzyloxy)-1-(1-(3-hydroxypropyl)-1H-indazol-5-yl)pyridin-2(1H)-one (50 mg, 88%) as a white solid. In accordance with the procedure of Example 1, the HCl salt was made to give the title compound as a white solid. 1H NMR (500 MHz, DMSO-d6) δ 8.12 (s, 1H), 7.73-7.71 (m, 2H), 7.62 (d, J=7.5 Hz, 1H), 7.48-7.36 (m, 5H), 7.33 (dd, J=9.0, 1.5 Hz, 1H), 6.10 (dd, J=7.5, 2.5 Hz, 1H), 5.99 (d, J=2.5 Hz, 1H), 5.15 (s, 2H), 4.50 (t, J=7.0 Hz, 2H), 3.38 (t, J=6.5 Hz, 2H), 2.01-1.96 (m, 2H); ESI MS m/z 376 [M+H]+.
