Hydrochloric Acid → 2-chloro-3,4,5-trimethoxybenzoic Acid

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Reaction Steps

Combine methyl 2-amino-3,4,5-trimethoxybenzoate (4.8 g, 20 mmol) and dichloromethane (20 mL). Cool in an ice bath. Add a solution of hydrochloric acid in dioxane (10 mL, 4 M, 40 mmol). Add polyethylene glycol 200 (20 mL) followed by sodium nitrite (2.76 g, 40 mmol). After 10 minutes add copper (I) chloride (3.96 g, 40 mmol). Warm to ambient temperature. After 18 hours, dilute the reaction mixture with ethyl acetate and extract with a 1 M aqueous solution of sodium hydroxide an then brine. Dry the organic layer over MgSO4, filter, and evaporate in vacuo to give a residue. the title compound. Chromatograph the residue on silica gel eluting sequentially with hexane and then 5% ethyl acetate/hexane to give methyl 2-chloro-3,4,5-trimethoxybenzoate: Rf=0.7 (silica gel, 20% ethyl acetate/toluene).

Provenance & Evidence