Reaction Steps
A 25-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 3-bromo-5-(1-oxo-3,4,6,7,8,9-hexahydropyrazino[1,2a]indol-2(1H)-yl)isonicotinaldehyde 101f (200 mg, 0.54 mmol), 3-(5-((2S,5R)-2,5-dimethyl-4-(oxetan-3-yl)piperazin-1-yl)pyridin-2-ylamino)-1-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2(1H)-one 155a (267 mg, 0.54 mmol), Pd(dppf)Cl2 (44 mg, 0.054 mmol), K3PO4 (229 mg, 1.08 mmol), sodium acetate (89 mg, 1.08 mmol), water (0.2 mL) and acetonitrile (10 mL). After three cycles of vacuum/argon flush, the mixture was heated at reflux for 2 h. It was then cooled to room temperature and filtered. The filtrate was concentrated under reduced pressure and the residue was purified by reverse-phase prep-HPLC to afford 157 (35.5 mg, 11%) as a yellow solid. MS-ESI: [M+H]+ 665.4. 1H NMR (500 MHz, CDCl3) δ 8.65-8.63 (m, 2H), 8.50 (s, 1H), 7.80 (s, 1H), 7.87 (s, 1H), 7.48-7.47 (m, 1H), 7.36 (d, J=7.5 Hz, 1H), 6.88 (s, 1H), 6.81 (d, J=9.0 Hz, 1H), 4.75-4.54 (m, overlap, 6H), 4.37-4.13 (m, overlap, 4H), 4.00-3.95 (m, 1H), 3.74-3.73 (m, 1H), 3.72 (s, 3H), 3.19-3.15 (m, 1H), 2.91-2.90 (m, 1H), 2.74-2.44 (m, overlap, 7H), 1.92-1.88 (m, 2H), 1.81-1.79 (m, 2H), 0.90-0.89 (m, 6H).
