Cesium carbonate → 2-Bromo-4-fluoro-6-(1-oxo-3,4,6,7,8,9-hexahydropyrido[3,4-b]-indolizin-2(1H)-yl)benzyl acetate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and reflux condenser was charged with 1,4-dioxane (60 mL), 101c (1.9 g, 6.0 mmol), 101g (400 mg, 2.0 mmol), and cesium carbonate (1.3 g, 4.0 mmol). After bubbling nitrogen through the resulting mixture for 30 minutes, Xantphos (120 mg, 0.2 mmol) and tris(dibenzylideneacetone)dipalladium(0) (180 mg, 0.2 mmol) were added, and the reaction mixture was heated at 100° C. for 12 h. After this time the reaction was cooled to room temperature, partitioned between ethyl acetate (40 mL) and water (40 mL), and filtered. The aqueous layer was separated and extracted with ethyl acetate (70 mL×3). The combined organic layer was washed with brine (30 mL) and dried over sodium sulfate. The drying agent was removed by filtration and the filtrate was concentrated under reduced pressure. The residue was purified on flash column eluting with 2:1 PE/EA to afford 101h (421 mg, 46%) as yellow solid. MS: [M+H]+ 435. 1H NMR (500 MHz, MeOD) δ 7.52-7.50 (m, 1H), 7.20-7.23 (m, 1H), 6.14 (s, 1H), 5.10-5.20 (m, 2H), 4.06-4.12 (m, 1H), 3.92-3.97 (m, 1H), 3.83-3.88 (m, 1H), 3.75-3.79 (m, 1H), 3.03-3.10 (m, 1H), 2.94-2.99 (m, 1H), 2.75-2.83 (m, 2H), 2.00-2.05 (m, 5H), 1.83-1.88 (m, 2H)

Herkunft & Nachweise