8-Hydroxyquinoline → tert-Butyl 6-methyl-8-(2-oxo-4-(6-(trifluoromethyl)pyridin-3-yl)pyridin-1(2H)-yl)3,4,5,6-tetrahydroazepino[4,3-b]indole-2(1H)-carboxylate

Participants

Reaction Conditions

Reaction Steps

tert-Butyl 8-bromo-6-methyl-3,4,5,6-tetrahydroazepino[4,3-b]indole-2(1H)-carboxylate (0.11 g, 0.29 mmol), 4-(6-(trifluoromethyl)pyridin-3-yl)pyridin-2(1H)-one (83 g, 0.35 mmol) and Cs2CO3 (0.10 g, 0.32 mmol) were suspended in DMSO (1.0 mL), and the air was removed under vacuum for 15 min. The system was flushed with Ar, and 8-hydroxyquinoline (13 mg, 0.087 mmol) and copper iodide (72 mg, 0.38 mmol) were added to the suspension. The evacuation/Ar flushing process was repeated twice more, and the reaction mixture was heated at 130° C. for 18 h under N2. The mixture was cooled, diluted with 5:1 MeOH/NH4OH (20 mL), and the resulting solution was stirred at ambient temperature for 30 min. The reaction was further diluted with CH2Cl2 (75 mL). The resulting solution was filtered through silica gel and the filtrate was concentrated under reduced pressure. The residue was diluted with CH2Cl2 and washed with brine (3×20 mL). The organic solution was dried over Na2SO4, filtered and concentrated to dryness. Flash chromatography (12 g ISCO column, (1:1 hexanes/EtOAc)/(80:18:2 CH2Cl2/MeOH/NH4OH), 100:0 for 5 column volumes, increased to 50:50 over 20 column volumes and held for 4 column volumes; increased to 0:100 over 10 column volumes and held for 5 column volumes) followed by preparative HPLC (Phenomenex Luna C18 (2), 250.0×50.0 mm, 10 micron, H2O with 0.05% TFA and CH3CN with 0.05% TFA) gave the title compound (67 mg, 42%) as a yellow film: 1H NMR (500 MHz, DMSO-d6) δ 9.19 (s, 1H), 8.50-8.48 (m, 1H), 8.05 (d, J=8.0 Hz, 1H), 7.85 (d, J=6.5 Hz, 1H), 7.54-7.51 (m, 2H), 7.03-6.99 (m, 2H), 6.78 (dd, J=7.5, 2.0 Hz, 1H), 4.60 (s, 2H), 3.69-3.65 (m, 5H), 3.00-2.99 (m, 2H), 1.96-1.90 (m, 2H), 1.36-1.30 (m, 9H); ESI MS m/z 539 [M+H]+.

Provenance & Evidence