(4-Bromo-3-fluorophenyl)(2,2-diethoxyethyl)sulfane → 5-Bromo-6-fluorobenzo[b]thiophene

Participants

Reaction Conditions

Reaction Steps

Polyphosphoric acid (13.9 g) was stirred in chlorobenzene (50 mL) at 130° C. (4-bromo-3-fluorophenyl)(2,2-diethoxyethyl)sulfane (7.7 g, 0.0238 mol) in chlorobenzene (15.4 mL) was added dropwise at 130° C. The mixture was then stirred at 130° C. for 10 h. The solvent was removed and the residue was extracted with toluene, hexane, and then water. The organic phase was combined and washed with saturated NaHCO3 solution and brine, and then dried over Na2SO4. The products 5-bromo-4-fluorobenzo[b]thiophene and 5-bromo-6-fluorobenzo[b]thiophene were obtained after purification via column chromatography (3.6 g, 65.5%).

Provenance & Evidence