Sulfuric Acid → 7-chloro-1H-isochromen-1-one

Participants

Reaction Steps

Concentrated sulphuric acid (15 ml) was added to 5-chloro-2(2-methoxyvinyl)-benzoic acid (4.43 g) at 0° C. The mixture was stirred for 2 hours, then diluted with ice/water. The product was extracted with ethyl acetate (3×15 ml) and the combined extracts washed with saturated sodium bicarbonate solution. The solution was dried (magnesium sulfate), filtered and concentrated. The residue was purified by flash chromatography (0-5% ethyl acetate/hexane) to afford the sub-title compound as a white solid (3.04 g, 81%); mp 109.8-110.9° C.; 1H NMR (400 MHz, CDCl3) δ 6.51(1H, d), 7.28-7.32(1H, m), 7.41(1H, d), 7.64-7.70(1H, m), 8.28(1H, m).

Provenance & Evidence