反应详情

温度

60 °C

To a solution of 2-methylindole-4-carboxylic acid methyl ester (4.3 g; prepared in Reference Example 9) in methanol—dioxane (10 ml+10 ml) was added 5N aqueous solution of sodium hydroxide (10 ml), and the mixture was stirred at 60° C. overnight. To the reaction solution was added 2N hydrochloric acid, and then extracted with ethyl acetate. The aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with water and a saturated aqueous solution of sodium chloride, successively, dried and concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (chloroform-methanol) to give the title compound (1.6 g) having the following physical data.

1. extractionextracted with ethyl acetate
2. extractionThe aqueous layer was extracted with ethyl acetate
3. washThe combined organic layer was washed with water
4. dry with materiala saturated aqueous solution of sodium chloride, successively, dried
5. concentrationconcentrated under reduced pressure
6. customThe residue was purified by column chromatography on silica gel (chloroform-methanol)