Dimethyl Sulfate → Methyl o-toluate

Participants

Reaction Steps

o-Toluic acid (500 mg, 3.67 mmol), dimethyl sulfate (695 mg, 5.51 mmol), and K2CO3 (558 mg, 4.04 mmol) were placed in a round bottom flask and diluted with acetone (10 mL). After purging the resulting suspension with argon for 5 min, the mixture was heated to reflux for 2 h. The reaction mixture was cooled and concentrated under reduced pressure to remove acetone. After adding water to the mixture, the solution was extracted with ethyl acetate (×3). The combined extracts were washed with brine, dried over anhydrous MgSO4, filtered, and concentrated in vacuo. The crude product was purified by flash chromatography on silica gel (Hex/EtOAc=9:1) to give 2-methylbenzoic acid methyl ester (Formula 4) (415 mg, 75%) as a white solid. Rf=0.5 (Hex:EtOAc=9:1); 1H NMR (300 MHz, CDCl3): δ 7.91 (dd, J=8.4 and 1.8 Hz, 1H), 7.40 (td, J=7.5 and 1.5 Hz, 1H), 7.24 (m, 2H), 3.89 (s, 3H), 2.60 (s, 3H).

Provenance & Evidence