Cesium carbonate → (1S,1aS,6bR)-ethyl 5-((7-oxo-5,6,7,8-tetrahydro-1,8-naphthyridin-4-yl)oxy)-1a,6b-dihydro-1H-cyclopropa[b]benzofuran-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

The mixture of Intermediate III (400 mg, 1.8 mmol), 5-fluoro-3,4-dihydro-1,8-naphthyridin-2(1H)-one (250 mg, 1.5 mmol) and cesium carbonate (801 mg, 2.3 mol) in DMF (20 mL) was stirred at 120° C. for 2 hrs. The reaction was diluted with water (10 mL) and extracted with ethyl acetate (2×10 mL). The combined organic phase was washed with brine (20 mL), dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel chromatography (eluted with EtOAc:PE=3:1) to obtain the title compound (360 mg, 54.6%) as a white solid.

Provenance & Evidence