1-Bromo-4-[(2,2-dimethoxyethyl)sulfanyl]benzene → 5-Bromo-1-benzothiophene

Participants

Reaction Steps

A mixture of polyphosphoric acid (10 g) in chlorobenzene (260 mL) was heated to reflux and added, under nitrogen, dropwise in one hour 1-bromo-4-(2,2-dimethoxy-ethylsulfanyl)-benzene (compound PRE12; 9.71 g, 35 mmol). The reaction mixture was then heated for 4 h until reaction is complete, cooled, quenched with water (150 mL) and extracted into methylene chloride. Combined organic layer was dried over Na2SO4 and concentrated to give a crude residue that was purified by flash chromatography (silica, eluting solvent: petroleum ether) to give 3.8 g of 5-bromo-benzo[b]thiophene (white solid) (Yield=51%).

Provenance & Evidence