Hydrochloric Acid → 1,3-Benzodioxol-5-ol, 4-chloro-

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Reaction Steps

To a cooled (−78° C.) solution of 5-methoxymethoxy-benzo[1,3]dioxole (5.0 g, 27.35 mmol) in THF (25 mL) was slowly added 2.5 M solution of n-BuLi in hexane and stirred at nitrogen atmosphere. After 30 minutes, a solution of hexachloroethane (12.95 g, 54.7 mmol) in THF (25 mL) was added and then resulting mixture was allowed to warm to room temperature and stirred for 7 h. The reaction was diluted with water (50 mL) and extracted with ethyl acetate (2×50 mL). The organic layer was dried (Na2SO4) and concentrated under vacuum to get crude product. The obtained product was dissolved in methanol (50 mL) and 0.5 mL conc. HCl and then heated at 50° C. for 2 h. The reaction was concentrated, dissolved in ethyl acetate (50 mL) and washed with saturated aqueous sodium bicarbonate. The solvent was evaporated under vacuum to give crude product. Silica gel column chromatography (30% CH2Cl2/Hexane) gave 4-chloro-benzo[1,3]dioxol-5-ol (3c) (2.5 g, 53%). 1H NMR (CDCl3) δ 5.12 (s, 1H), 6.0 (s, 2H), 6.47 (d, 1H, J=9.0 Hz), 6.62 (d, 1H, J=9.0 Hz).

Provenance & Evidence