Ethyl chloroacetate → Ethyl 4-chlorobenzofuran-2-carboxylate

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Reaction Steps

Ethyl chloroacetate (8.0 mL, 1.3 eq.) was added to a mixture of 2-chloro-6-hydroxy-benzaldehyde (Example 1a), 9.0 g, 57 mmol) and potassium carbonate (16.0 g, 114 mmol) in DMF (100 mL) at rt. The reaction mixture was heated at +120° C. for 1.5 h, cooled to room temperature and filtered through a short bed of Celite. The filtrate was acidified to pH 2 with 5 M HCl and the solution was extracted with dichloromethane (2×100 mL). The combined organic extracts was washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude residue was purified by silica gel column chromatography by using hexane/ethyl acetate (9/1) as eluent to give the title compound. Yield: 10 g (77%). 1H NMR (400 MHz, CDCl3) δ ppm 1.44 (t, 3H) 4.56 (q, 2H) 7.29-7.32 (m, 1H) 7.35-7.40 (m, 1H) 7.49-7.52 (m, 1H) 7.60 (s, 1H).

Provenance & Evidence