反应详情

A solution of 6.5 g (31.5 mmole) of dicyclohexyl carbodiimide in 40 ml of absolute methylene chloride is added at room temperature over a period of approximately 3 minutes to a solution of 8.1 g (30 mmole) of crude 5-chloro-2-hydroxy-4-(piperidin-1-yl)-phenylacetic acid in 50 ml of absolute methylene chloride. The reaction mixture is stirred for 30 minutes at room temperature. The precipitated dicyclohexylurea is filtered with suction and washed with methylene chloride. The filtrate is concentrated by evaporation in a vacuum rotary evaporator and the residue is chromatographed over silica gel using methylene chloride/hexane (1:1) as eluant. recrystallisation from hexane yields 5-chloro-6-(piperidin-1-yl)-benzofuran-2(3H)-one having a melting point of 129°-131°.

1. filtrationThe precipitated dicyclohexylurea is filtered with suction
2. washwashed with methylene chloride
3. concentrationThe filtrate is concentrated by evaporation in a vacuum rotary evaporator
4. customthe residue is chromatographed over silica gel
5. customrecrystallisation from hexane