Hydrochloric Acid → 8-Fluoro-2,3-dihydro-4H-1-benzopyran-4-one

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Reaction Steps

A solution of 2-fluorophenol (Compound 1-1, 3.0 g) in N,N-dimethylformamide (7.0 ml) was added to a solution of 50% sodium hydride (3.22 g) in N,N-dimethylformamide (100 ml) in a nitrogen atmosphere with cooling in an ice bath. After stirring at the same temperature for 30 minutes, a solution of 3-bromo-propionic acid (4.91 g) in N,N-dimethylformamide (8.0 ml) was added. The mixture was returned to room temperature and stirred at the same temperature for 24 hours. The pH was adjusted to 1 to 2 with 1 N hydrochloric acid (100 ml) to terminate the reaction. The aqueous layer was extracted with ethyl acetate, and the organic layer was washed with brine. The organic layer was dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was crystallized by adding a mixed solvent of 20% ethyl acetate-hexane to obtain the title compound (1.53 g). (1-2) The title compound was synthesized by the following alternative method.

Provenance & Evidence