Phenyltrimethylammonium bromide dibromide → 1-(Benzo[b]thiophen-7-yl)-2-bromopropan-1-one

Beteiligte Stoffe

Reaktionsschritte

Phenyltrimethylammonium tribromide (1.52 g) was added in portions under nitrogen at 0° C. over 30 minutes to a stirred solution of 1-(benzo[b]thiophen-7-yl)propan-1-one (0.77 g) in tetrahydrofuran (110 ml), then the mixture was stirred at ambient temperature for 18 hours. Further phenyltrimethylammonium tribromide (0.76 g) was added and the mixture was heated under reflux for 4 hours. Further phenyltrimethylammonium tribromide (0.76 g) was added, then the mixture was heated under reflux for 90 minutes, cooled to ambient temperature and filtered. The solvent was removed in vacuo and the residue was purified by flash chromatography over silica using a 7:3 mixture of petroleum ether (b.p. 60-80° C.) and dichloromethane as eluant. Appropriate fractions were combined and the solvents removed in vacuo to give 1-(benzo[b]thiophen-7-yl)-2-bromopropan-1-one (0.71 g) as an oil which was used without further purification.

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