Hydrochloric Acid → 5-Fluoro-2,3-dihydrobenzofuran-6-ol

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 5-fluoro-6-hydroxy-benzofuran-3-one (551 mg, 3.28 mmol) in ethanol (10 mL) was added hydrazine hydrate (3.75 mL, 76.93 mmol), and the reaction was heated to reflux for 30 minutes. The reaction was subsequently concentrated in vacuo. The residue was then dissolved in ethylene glycol (10 mL), and then treated with potassium hydroxide (551.64 mg, 9.83 mmol). The reaction was then heated to 1500° C. for 3 hours. The reaction was poured into 2M aq. HCl (100 mL), and extracted with EtOAc (100 mL). The organic phase was washed with brine, dried over MgSO4, filtered and concentrated in vacuo. The residue was suspended in DCM (50 mL), and the reaction was filtered. The filtrate was concentrated in vacuo and loaded onto a silica column (25 g, SNAP cartridge), which was eluted with EtOAc:isohexane 0% to 50%. Fractions containing desired product were combined and concentrated in vacuo to give 5-fluoro-2,3-dihydrobenzofuran-6-ol (D95) (190.4 mg, 1.2352 mmol, 37.7% yield) as a colourless oil which crystallised on standing;

Provenance & Evidence