Lithium Bromide → Benzo(b)thiophen-4-ol

Participants

Reaction Steps

5-Bromo-6,7-dihydro-5H-benzo[b]thiophen-4-one (199, 77% pure, 8.7 g, 28.9 mmol), LiBr (5.7 g, 65.1 mmol) and Li2CO3 (4.3 g, 57.8 mmol) are placed under argon in 300 ml of DMF and refluxed for 3 h. The reaction mixture is allowed to cool down to room temperature and evaporated under high vacuum. After addition of ice water and cold 2M aqueous HCl solution the mixture is extracted with diethyl ether. The organic layers are extracted with 2M NaOH and the combined aqueous layers are acidified with concentrated HCl. The product is extracted twice with ethyl acetate and the organic layers are washed with saturated NaCl solution, dried over Na2SO4 and evaporated under reduced pressure.

Provenance & Evidence