Hydrochloric Acid → HCID 15550635, compound

Participants

Reaction Steps

1Bromo-2,3,4,5-tetrafluorobenzene (5.0 g, 21.8 mmol) was mixed at ambient temperature with 20% fuming sulfuric acid (20 ml). The mixture was heated at 40° C. for 3 h and at 110° C. for 2 h. The reaction mixture was allowed to cool to ambient temperature and poured onto 12 g of crushed ice. The mixture was acidified dropwise with concentrated HCl (2 ml) until a solid, consisting mostly of 2-bromo-3,4,5,6-tetrafluorophenylsulfonic acid was formed. The solid was filtered, washed with 12N HCl, and dried under high vacuum to afford 5.3 g of 2-bromo-3,4,5,6-tetrafluorophenylsulfonic acid as a white hygroscopic solid that was used without further purification. To the sulfonic acid (3.0 g, 9.7 mmol) was then added phosphorous pentachloride (8.0 g, 38.4 mmol) in small portions, at ambient temperature (Caution: exothermic reaction with significant evolution of HCl). The reaction was allowed to stir for 20 minutes after the final addition of phosphorous pentachloride. The reaction mixture was then poured onto crushed ice and the white solid that formed was filtered and dried to afford 2.8 g of the title compound, which was used without further purification. MS (EI): 328 (30, M+), 293 (70), 229 (30), 148 (100).

Provenance & Evidence