Cesium carbonate → 1-cyclopentyl-5-iodo-1H-indazole

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-fluoro-5-iodobenzaldehyde (500 mg, 2 mmol), cyclopentylhydrazine (273 mg, 2 mmol), and cesium carbonate (1.91 g, 5 mmol) in NMP (5 ml) was stirred at 100° C. overnight. Then KOtBu (560 mg, 5 mmol) and DMF (10 ml) were added, and the mixture was stirred at 150° C. for 5 h. After cooling to r.t., the mixture was diluted with ethyl acetate (100 ml), and washed with water (3×50 ml), and dried. Evaporation of solvent afforded batch residue, which was dissolved in acetonitrile (50 ml), and the insoluble material was removed by filtration. Flash chromatography on silica gel (n-heptane/ethyl acetate) afforded yellow oil, 158 mg (25%).

Provenance & Evidence