Potassium Acetate → 2-Bromo-4-fluoro-6-(1-oxo-6,7,8,9-tetrahydropyrazino[1,2-a]indol-2(1H)-yl)benzaldehyde

Participants

Reaction Conditions

Reaction Steps

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 121e (500 mg, 2.66 mmol), 2,6-dibromo-4-fluorobenzaldehyde (1.50 g, 5.32 mmol), and potassium acetate (521 mg, 5.32 mmol). After bubbling argon through the suspension for 30 minutes, 4,7-dimethoxy-1,10-phenanthroline (638.4 mg, 2.66 mmol) and cuprous iodide (506 mg, 2.66 mmol) were added. The system was subjected to three cycles of vacuum/argon flush and then heated at 100° C. for 16 h. It was then cooled to room temperature and filtered. The solid was washed with dichloromethane (2×100 ml). The combined filtrate was concentrated under reduced pressure and the residue was purified by silica-gel column chromatography eluting with petroleum ether/ethyl acetate (10:1 to 3:1) to afford 121f (510 mg, 49%) as a yellow solid. MS: [M+H]+ 389.

Provenance & Evidence