Tetrahydrofuran → 1-(2,3-Difluoro-6-nitrophenyl)propan-2-one

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Reaction Steps

12.1 g (303 mmol) of 60% sodium hydride was added to 45 ml of tetrahydrofuran, and while cooling with a freezing mixture, 90 ml of tetrahydrofuran containing 39.0 g (300 mmol) of ethyl acetoacetate was dropped to the solution below 20° C. through 30 minutes. After the solution was stirred for 1 hour as was, 90 ml of tetrahydrofuran solution containing 26.6 g (150 mmol) of 2,3,4-trifluoronitrobenzene was dropped to the solution below 10° C. through 30 minutes, and the solution was stirred overnight at room temperature. 27 ml of acetic acid was added to the solution, and the solvent was removed by distillation. The solution was extracted with 500 ml of chloroform, and after drying over magnesium sulfate, the solvent was removed by distillation. 30 ml of 4N hydrochloric acid and 25 ml of acetic acid were added to the solution, and the solution was heated at reflux for 24 hours. 550 ml of concentrated hydrochloric acid and 550 ml of acetic acid were added to the solution, and the solution was heated at reflux for 16 hours. After air-cooling, the solution was extracted with 1 l of chloroform and was washed with 500 ml of water two times. The solution was further washed with 300 ml of aqueous saturated sodium hydrogen carbonate solution two times, and after drying over magnesium sulfate, the solvent was removed by distillation. The residue was separated by the column chromatography (silica gel 300 g, eluent solvent; chloroform: n-hexane=1 :3) to obtain 31.2 g of the subject compound (148) in a 90% yield.

Provenance & Evidence