Cesium carbonate → 4-Chloro-2-(1-oxo-6,7,8,9-tetrahydropyrazino[1,2-a]indol-2(1H)-yl)nicotinaldehyde

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 1,4-dioxane (15 mL), 2-bromo-4-chloronicotinaldehyde 103a (503 mg, 2.28 mmol), 195e (142 mg, 0.76 mmol), cesium carbonate (490 mg, 1.5 mmol), CuI (143 mg, 0.76 mmol), and 4,7-dimethoxy-1,10-phenanthroline (127 mg, 0.52 mmol). After three cycles of vacuum/argon flush, the mixture was heated at 80° C. for 10 hrs. It was then cooled to room temperature and filtered. The filtrate was washed with brine and concentrated under reduced pressure. The resulting residue was purified with silica-gel column chromatography eluting with 1:4 ethyl acetate/petroleum ether to afford 195f (160 mg, 65%) as a yellow solid. MS-ESI: [M+H]+ 328.

Provenance & Evidence