Reaction Steps
A suspension of tert-butyl 7-bromo-1-((tert-butyldimethylsilyloxy)methyl)-9-methyl-3,4-dihydro-1H-pyrido[3,4-b]indole-2(9H)-carboxylate (727 mg, 1.47 mmol), 4-(benzyl-oxy)pyridin-2(1H)-one (591 mg, 2.94 mmol), CuI (110 mg, 0.576 mmol), 8-hydroxyquinoline (84 mg, 0.58 mmol) and Cs2CO3 (720 mg, 2.21 mmol) in DMSO (10 mL) was degassed under reduced pressure for 45 min. The suspension was put under Ar and heated at 135° C. with stirring for 14 h. The suspension was cooled, 1:1 MeOH/NH4OH (40 mL) was added, and the resulting suspension was stirred for 30 min. CH2Cl2 was added and the phases were separated. The aqueous phase was extracted with CH2Cl2, and the combined organic extracts were washed with brine, dried over Na2SO4 and concentrated under reduced pressure. Flash chromatography (silica gel, (1:1 EtOAc/hexanes)/(9:0.9:0.1 Et2O/MeOH/NH4OH) 100:0 to 0:100) afforded the amine as a yellow amorphous solid. A 1.0 M solution of TBAF in THF (0.57 mL, 0.57 mmol) was added to a solution of the above yellow semi-solid in THF (10 mL) under N2, and the resulting solution was stirred at 25° C. for 1.5 h. H2O and CH2Cl2 were added to the solution and the phases were separated. The aqueous phase was extracted with CH2Cl2, and the combined organic phases were dried over Na2SO4 and concentrated under reduced pressure. Flash chromatography (silica gel, (1:1 EtOAc/hexanes)/(9:0.9:0.1 Et2O/MeOH/NH4OH) 100:0 to 0:100) yielded a yellow amorphous solid. TFA (2 mL) was added to a solution of the above amorphous solid in CH2Cl2 (10 mL) under N2, and the resulting solution was stirred at 25° C. for 1 h. The solution was concentrated under reduced pressure. The resulting residue was diluted with CH2Cl2 and neutralized with a saturated aqueous NaHCO3 solution. The phases were separated. The organic phase was dried over Na2SO4 and concentrated under reduced pressure. Flash chromatography (silica gel, (1:1 EtOAc/hexanes)/(9:0.9:0.1 CH2Cl2/MeOH/NH4OH) 100:0 to 0:100) yielded the title compound (56 mg, 9%) as a viscous oil: 1H NMR (500 MHz, CDCl3) δ 7.56 (d, J=8.0 Hz, 1H), 7.46-7.37 (m, 5H), 7.32 (d, J=7.5 Hz, 1H), 7.30 (d, J=1.5 Hz, 1H), 7.03 (dd, J=8.0, 1.5 Hz, 1H), 6.11 (d, J=2.5 Hz, 1H), 6.06 (dd, J=7.5, 2.5 Hz, 1H), 5.08 (s, 2H), 4.14 (dd, J=10.0, 4.5 Hz, 1H), 3.80 (dd, J=10.0, 4.5 Hz, 1H), 3.69-3.62 (m, 4H), 3.23 (ddd, J=14.0, 4.5, 4.5 Hz, 1H), 3.12-3.05 (m, 1H), 2.78-2.73 (m, 2H); ESI MS m/z 416 [M+H]+.
