Stannous Chloride → 1,3-Dihydro-2,1-benzisothiazole 2,2-dioxide

Participants

Reaction Conditions

Reaction Steps

The title compound was prepared using the method described in WO 98/32438 A1. To a solution of 2-nitro-alpha-toluenesulfonyl chloride (5.1 g, 21.6 mmol) in anhydrous ethyl acetate (250 mL) was added tin (II) chloride (19.3 g, 86 mmol). The reaction was stirred overnight at 70° C., then poured onto ice and neutralized with saturated aqueous sodium bicarbonate. The solution was filtered through Celite, extracted with ethyl acetate, and the organic layer concentrated. To the crude residue was added anhydrous methylene chloride (200 mL) and triethylamine (5 mL). The solution was stirred overnight at room temperature and concentrated under reduced pressure. The product was obtained by silica gel column chromatography (30-100% ethyl acetate in hexanes) followed by recrystallization from methylene chloride/hexanes to give a white solid. (0.24 g, 6.5%). 1H NMR (CDCl3, 300 MHz) δ 7.30-7.22 (m, 2H), 7.07-7.02 (t, 1H, J=7.4 Hz), 6.89-6.86 (dd, 1H, J=0.6, 8.1 Hz), 6.66 (br s, 1H), 4.39 (s, 1H).

Provenance & Evidence