反应详情

A solution of 2.40 g (9.4 mmole) of 5-chloro-3-hydroxy-6-(piperidin-1-yl)-2,3-dihydrobenzofuran in 25 g of polyphosphoric acid is maintained at 60° for 20 minutes, then ice and water are added and the whole is adjusted to pH 7 with solid sodium carbonate. The reaction mixture is extracted twice with methylene chloride. The organic phases are washed with water, combined, dried over magnesium sulphate and concentrated in a vacuum rotary evaporator. The residue is chromatographed over silica gel using methylene chloride as eluant (Rf =0.63). In that manner, 5-chloro-6-(piperidin-1-yl)-benzofuran is obtained in the form of an oil which distills at 96°-97°/1.5 torr.

1. extractionThe reaction mixture is extracted twice with methylene chloride
2. washThe organic phases are washed with water
3. dry with materialdried over magnesium sulphate
4. concentrationconcentrated in a vacuum rotary evaporator
5. customThe residue is chromatographed over silica gel