Methyl iodide → 2-Methoxy-5-(3-methylsulfanyl-[1,2,4]triazol-4-yl)-benzoic acid methyl ester

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Reaction Steps

Treat a stirred mixture of 2-methoxy-5-(5-thioxo-1,5-dihydro-[1,2,4]triazol-4-yl)-benzoic acid methyl ester (3.80 g, 14.38 mmol), potassium carbonate (2.19 g, 15.8 mmol) and anhydrous acetone (60 mL) with methyl iodide (1.07 mL, 17.25 mmol) added dropwise via syringe. Reflux the stirred mixture for 2.5 hours, cool, filter and wash the filter cake twice with acetone. Combine the acetone phases, concentrate in vacuo, dissolve the residue in ethyl acetate and wash with NaHCO3 solution. Extract the combined aqueous phases three times with ethyl acetate. Combine the ethyl acetate phases, wash with saturated NaHCO3 and brine, dry (MgSO4), filter and concentrate in vacuo to afford an oil. Purify the oil by flash chromatography (silica gel, 5.5×15.2 cm) eluting with ethyl acetate and then with 5% methanol in dichloromethane after elution of the starting material. Concentrate the appropriate fractions to afford 2.89 g of 2-methoxy-5-(3-methylsulfanyl-[1,2,4]triazol-4-yl)-benzoic acid methyl ester as a colorless solid.

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