Methanol → 2-Carbomethoxy 4,5-dichlorobenzoic acid

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Reaction Steps

To methanol (200 mL) was added sodium hydride (2.72 g, 60% dispersion, 68.0 mmol) portionwise under nitrogen at ambient temperature. To the solution was then added a solution of 4,5-dichlorophthalic anhydride (5.90 g, 27.2 mmol) in methanol (50 mL) dropwise under nitrogen at room temperature. The reaction was stirred for one hour and then concentrated to remove the methanol. The residue was taken up in aqueous 10% potassium carbonate solution and extracted with ethyl acetate (2×). The aqueous portion was acidified to pH 2 with 10% hydrochloric acid and extracted with ethyl acetate (3×), dried (Na2SO4) and concentrated to afford the title compound. 1H NMR (300 MHz, DMSO-d6) δ ppm 3.81 (s, 3H) 7.94-8.01 (m, 2H) 13.60-13.70 (br, 1H); MS (+DCI/NH3) m/z 266.0 [M+NH4]+.

Provenance & Evidence