反应详情

7 ml of 5N hydrochloric acid are added to a mixture of 9.1 g (50 mmole) of 6-amino-5-chloro-3-methylbenzofuran, 10 ml (78 mmole) of 2,5-dimethoxytetrahydrofuran and 200 ml of dioxane and the whole is stirred at room temperature for 16 hours. The whole is subsequently concentrated by evaporation in vacuo and the residue is chromatographed over silica gel with petroleum ether/methylene chloride. Crystallisation of the resulting product from petroleum ether yields 5-chloro-3-methyl-6-(pyrrol-1-yl)-benzofuran having a melting point of 49°-52°.

1. concentrationThe whole is subsequently concentrated by evaporation in vacuo
2. customthe residue is chromatographed over silica gel with petroleum ether/methylene chloride
3. customCrystallisation of the resulting product from petroleum ether