반응 단계
5-Bromo-3-chloro-6-fluoro-2-methylquinoxaline (600), (242 mg, 0.878 mmol) and 2-amino-2-methylpropan-1-ol (Aldrich Chemical Company) (0.42 mL, 4.39 mmol) in DMSO (4.0 mL) was stirred at 100° C. (17 h). The reaction mixture was treated with EtOAc (50 mL), and washed with saturated aq. NaHCO3 (2×25 mL) and then with brine (1×25 mL). The organic layer was dried over MgSO4, filtered and concentrated. The crude product was purified using an ISCO Combiflash Rf (25 g Thomson SingleStep column with a gradient of 0-80% EtOAc in hexanes) affording 2-((8-bromo-7-fluoro-3-methylquinoxalin-2-yl)amino)-2-methylpropan-1-ol (370a) (112 mg, 0.34 mmol, 39% yield) as a crystalline light purple solid. 1H NMR (400 MHz, CDCl3) δ ppm 7.75 (1H, dd, J=9.0, 5.7 Hz), 7.19 (1H, t, J=8.6 Hz), 5.42 (1H, br. s.), 5.07 (1H, br. s.), 3.85 (2H, d, J=4.1 Hz), 2.56 (3H, s), 1.56 (6H, s). 19F NMR (376 MHz, CDCl3) δ ppm −102.16 (1F, s). m/z (ESI, +ve ion) 328.0/330.0 (M+H)+. A 20 mL glass microwave reaction vessel was charged with 6,7-dihydro-1H-pyrrolo[3,2-c]pyridin-4(5H)-one (607) (140 mg, 1.03 mmol), bis(1,5-cyclooctadiene)di-mu-methoxydiiridium(I) (Strem Chemicals,) (20.45 mg, 0.031 mmol), 4,4-di-tert-butyl-2,2-dipyridyl (Aldrich Chemical Company, 16.56 mg, 0.062 mmol), (BPin)2 (Aldrich Chemical Company, 287 mg, 1.13 mmol) and purged with argon then treated with methyl tert-butyl ether (3.0 mL, 25.2 mmol) The reaction mixture was stirred at 50° C. for 1 h 15 min. The crude reaction mixture was passed through a pad of basic alumina (Aldrich, Brockmann I, standard grade ca. 150 mesh 58A) rinsing with DCM first (ca. 8 mL) then eluting with 5% MeOH in DCM (ca. 15 mL) affording crude boronic ester (609) as a dark brown oil. This material was concentrated and used in a subsequent Suzuki coupling without further purification. m/z (ESI, +ve) 263.5 (M+H)+. A 5-mL glass microwave reaction vessel was charged with 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-6,7-dihydro-1H-pyrrolo[3,2-c]pyridin-4(5H)-one (609) (270 mg, 1.03 mmol), K2PO4 (217 mg, 1.02 mmol), Pd2dba3 (Strem Chemicals, 15.63 mg, 0.017 mmol), Xphos (Strem Chemicals 16.27 mg, 0.034 mmol) and 2-((8-bromo-7-fluoro-3-methylquinoxalin-2-yl)amino)-2-methylpropan-1-ol (370a) (112 mg, 0.34 mmol) in dioxane (2.0 mL) and water (0.66 mL). The reaction mixture was stirred and heated in a microwave reactor at 110° C. for 40 min. The reaction mixture was treated with water, extracted with EtOAc (2×25 mL), washed with brine and concentrated. The crude residue was purified on the ISCO Combiflash RF (25 g Thomson SingleStep column, using a gradient of 0-15% MeOH in DCM) affording 2-(6-fluoro-3-((1-hydroxy-2-methylpropan-2-yl)amino)-2-methylquinoxalin-5-yl)-6,7-dihydro-1H-pyrrolo[3,2-c]pyridin-4(5H)-one (83.1 mg, 0.22 mmol, 63% yield) as a light yellow amorphous solid after drying overnight under vacuum. 1H NMR (400 MHz, DMSO-d6) δ ppm 12.12 (1H, br. s.), 7.66 (1H, dd, J=9.0, 5.9 Hz), 7.32 (1H, dd, J=11.0, 9.0 Hz), 7.01 (1H, br. s.), 6.78 (1H, t, J=2.4 Hz), 5.99 (1H, s), 5.15 (1H, t, J=5.7 Hz), 3.61 (2H, d, J=5.3 Hz), 3.45 (2H, td, J=6.8, 2.3 Hz), 2.88 (2H, t, J=6.8 Hz), 1.45 (6H, s). 19F NMR (377 MHz, DMSO-d6) δ ppm −111.08 (1F, s). m/z (ESI, +ve) 384.1 (M+H)+.
