Cesium carbonate → 2-Bromo-4-fluoro-6-(1-oxo-6,7,8,9-tetrahydropyridazino[4,5-b]indolizin-2(1H)-yl)benzaldehyde

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Reaction Conditions

Reaction Steps

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 127e (450 mg, 2.4 mmol), 2,6-dibromo-4-fluorobenzaldehyde (2.0 g, 7.2 mmol), cesium carbonate (1.6 g, 4.8 mmol), and 1,4-dioxane (50 mL). After bubbling nitrogen through the resulting mixture for 10 minutes, copper(I) iodide (450 mg, 2.4 mmol) and 4,7-dimethoxy-1,10-phenanthroline (571 mg, 2.4 mmol) were added, and the reaction mixture was heated at 90° C. for 12 h. After this time the reaction was cooled to room temperature and filtered. The filtrate was partitioned between methylene chloride (40 mL) and water (40 mL). The aqueous layer was separated and extracted with methylene chloride (3×30 mL). The combined organic layer was washed with brine (50 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 by silica-gel column chromatography eluting with 1:2 ethyl acetate/petroleum ether to afford 127f as a brown solid (251 mg, 31%). MS-ESI: (M+H)+ 390.0.

Provenance & Evidence