Ethyl Acetate → Methyl 2-[[(dimethylamino)carbothioyl]oxy]-4-fluorobenzoate

Participants

Reaction Steps

4-Fluorosalicylic acid (10.0 g, 64 mmol) was dissolved in methanol (300 ml), and concentrated sulfuric acid (6.3 g, 64 mmol) was added thereto. The reaction mixture was refluxed for 48 hrs. The solvent was evaporated, and the residue was neutralized with 2 N aqueous sodium hydroxide solution. Ethyl acetate was added to the mixture. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. The solvent was evaporated to give methyl 4-fluorosalicylate (10.0 g, 92%) as white crystals. Methyl 4-fluorosalicylate (10.0 g, 58 mmol) and N,N-dimethylthiocarbamoyl chloride (9.6 g, 77 mmol) were dissolved in DMF (100 ml), and 1,4-diazabicyclo[2.2.2]octane (8.5 g, 75 mmol) was added thereto. The reaction mixture was stirred at room temperature for 7 hrs. The reaction mixture was combined with ethyl acetate and water. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. The solvent was evaporated. The residue was subjected to a silica gel column chromatography. The fractions eluted with ethyl acetate-hexane (1:5, v/v) were collected, concentrated and recrystallized from ethyl acetate-hexane to give the titled compound (12.1 g, 80%) as white crystals.

Provenance & Evidence