反应详情

A solution of 2.51 g (10.0 mmole) of 5-chloro-6-(piperidin-1-yl)-benzofuran-3(2H)-one in 15 ml of acetic anhydride and 15 ml of glacial acetic acid is maintained at 100° for 24 hours. The reaction mixture is subsequently poured onto ice and extracted with methylene chloride. The organic phases are washed with water, combined, dried over sodium sulphate and concentrated in a vacuum rotary evaporator. The crude 3-acetoxy-5-chloro-6-(piperidin-1-yl)-benzofuran so obtained is dissolved in 15 ml of absolute methanol, 250 mg of platinum oxide are added and the whole is hydrogenated at 3 atmospheres and room temperature. The catalyst is filtered off and the filtrate is 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. additionThe reaction mixture is subsequently poured onto ice
2. extractionextracted with methylene chloride
3. washThe organic phases are washed with water
4. dry with materialdried over sodium sulphate
5. concentrationconcentrated in a vacuum rotary evaporator
6. customThe crude 3-acetoxy-5-chloro-6-(piperidin-1-yl)-benzofuran so obtained
7. customis hydrogenated at 3 atmospheres and room temperature
8. filtrationThe catalyst is filtered off
9. concentrationthe filtrate is concentrated in a vacuum rotary evaporator
10. customThe residue is chromatographed over silica gel