Hydrochloric Acid → 1,1-Dioxo-1H-1lambda*6*-benzo[b]thiophene-6-sulfonyl chloride

Participants

Reaction Conditions

Reaction Steps

A mixture of 6-amino-1,1-dioxobenzo[b]thiophene (253 mg, 1.39 mmol) and 30% aqueous HCl (1.53 mL) was cooled to 0° C. in an open flask, and then 40% aqueous sodium nitrite (754 μL) was added dropwise over 2.25 minutes. The mixture was stirred at 0° C. for 15 minutes, and then 30% aqueous HCl (768 μL) and solid CuSO4 (20.4 mg, 0.128 mmol) were added. To this mixture was added 40% aqueous NaHSO3 (2.39 mL) dropwise over 6 minutes, and the reaction was stirred at 0° C. for 2.5 hours. The reaction was diluted with water (50 mL) and extracted with dichloromethane (2×50 mL). The combined organic layers were washed with brine (75 mL), dried over Na2SO4, filtered and evaporated. The product was purified by flash column chromatography through 20 g of silica gel using CH2Cl2 to give the title compound (171 mg, 46%) as a pale yellow solid. 1H-NMR (300 MHz, CDCl3) δ8.35 (m, 1H), 8.26 (dd, 1H, J=8.0, 1.8 Hz), 7.65 (d, 1H, J=8.0 Hz), 7.34 (dd, 1H, J=7.0, 1.0 Hz), 7.02 (d, 1H, J=7.0 Hz).

Provenance & Evidence