Benzo(B)Thiophene → 2-Acetylbenzothiophene

Participants

Reaction Conditions

Reaction Steps

n-Butyllithium (1.6 M solution in hexanes; 74.6 ml) was added dropwise under nitrogen at 0° C. to a stirred solution of benzo[b]thiophene (25.0 g) in ether (350 ml), then the mixture cooled to −70° C. and a solution of N-methoxy-N-methylacetamide (19.21 g) in ether (100 ml) was added dropwise. The mixture was stirred at ambient temperature for 18 hours, then it was poured into saturated aqueous ammonium chloride solution (400 ml). The organic phase was separated, washed with water (300 ml) and saturated aqueous sodium chloride solution (300 ml), dried (Na2SO4) and the solvents were removed in vacuo. The residue was triturated with petroleum ether (b.p. 60-80° C.) (50 ml) and the resulting solid was collected by filtration and dried in vacuo to give 1-(benzo[b]thiophen-2-yl]ethan-1-one (18.7 g) as a brown solid, m.p. 78-81° C.

Provenance & Evidence