Chlorosulfonic acid → 5-(Chlorosulfonyl)-2-methylbenzoic acid methyl ester

Participants

Reaction Steps

Chlorosulfonic acid (106.2 ml) was carefully added over 1 min with stirring under nitrogen to 2-methyl-benzoic acid methyl ester (55.9 ml, 0.4 mol). The reaction mixture was placed in an oil bath preheated to 100° C. for 15 min, then poured onto ice (1000 ml). The resulting precipitate was filtered and dissolved in ethyl acetate (400 ml). The ethyl acetate solution was washed sequentially with 10×300 ml saturated aqueous sodium bicarbonate, 300 ml water and 300 ml brine, dried (anhydrous sodium sulfate) and concentrated under reduced pressure to yield the title compound as a yellowish oil (37.3 g, 37% yield). 1H NMR (400 MHz, CDCl3) δ, 2.74 (s, 3H), 3.96 (s, 3H), 7.52 (d, 1H), 8.04 (m, 1H), 8.58 (d, 1H).

Provenance & Evidence