Sulfuric Acid → 4,6-Dimethyl-benzo[d]isothiazole-3-carboxylic acid methyl ester

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Reaction Steps

To a solution of 4,6-Dimethyl-1,2-benzisothiazole-3-carboxylic acid (10 mg, 0.048 mmol) in MeOH (5 mL) was added conc. H2SO4 (0.1 mL) at room temperature. The solution was heated up to 60 C for 24 hours. The solution was cooled down and was neutralized with sat. NaHCO3. The solution was extracted with EtOAc. The combined organic layer was dried with MgSO4 and was filtered. The filtrate was concentrated and the residue was purified by CombiFlash with 20% EtOAc in Hexane as the eluent to afford the desirable product 4,6-Dimethyl-benzo[d]isothiazole-3-carboxylic acid methyl ester, CAS: 4,6-Dimethyl-1,2-benzisothiazole-3-carboxylic acid methyl ester (10 mg, 94%) as colorless oil.

Provenance & Evidence