Hydrochloric Acid → Benzo(b)thiophene-2,3-dione

Participants

Reaction Steps

To a solution of benzenthiol (1 ml, 9.7 mmol) in Et2O (30 ml) at 0° C. oxalyl chloride (0.94 ml, 10.7 mmol) was added dropwise. The mixture was stirred at room temperature for 1.5 hour, then, the solvent was evaporated under reduced pressure. The crude was dissolved in CH2Cl2 (40 ml) and a solution of AlCl3 (4.75 g, 35 mmol) in CH2Cl2 (32 ml) was added dropwise at 0° C. The mixture was stirred for 16 hours at room temperature, then, ice and 1M HCl were added until a clear mixture was obtained. After 1 hour, the phases were separated and the aqueous layer was extracted with CH2Cl2 (3×30 ml). The collected organic phases were dried over Na2SO4, filtered and evaporated, affording 18 (1.2 g, 78%) as orange solid that was used without further purification.

Provenance & Evidence