反应详情

A solution of 6.5 g (31.5 mmoles) of dicyclohexylcarbodiimide in 40 ml of absolute methylene chloride is added at room temperature in the course of approximately 3 minutes to a solution of 8.1 g (30 mmoles) of crude 5-chloro-2-hydroxy-4-(piperidin-1-yl)-phenylacetic acid in 50 ml of absolute methylene chloride. The reaction mixture is stirred at room temperature for 30 minutes. The precipitated dicyclohexylurea is filtered off 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 with the eluant methylene chloride/hexane (1:1). Recrystallisation from hexane yields 5-chloro-6-(piperidin-1-yl)-benzofuran-2(3H)-one having a melting point of 129°-131° C.

1. filtrationThe precipitated dicyclohexylurea is filtered off 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 with the eluant methylene chloride/hexane (1:1)
5. customRecrystallisation from hexane