反应详情

To 4-methoxy-1-methyl-1H-indole-2-carboxylic acid (2.92 mmol, 600 mg) in dichloromethane (30 ml) under a nitrogen atmosphere was added boron tribromide (6.96 mmol, 671 μl, 1745 mg) keeping the temperature at 0 to 5° C. After stirring the reaction mixture at room temperature for three hours it was treated with 2N aqueous sodium hydroxide (to give a pH of 9) and stirred for additional 10 minutes. The aqueous phase was separated and neutralized with 2 N hydrochloric acid at 0° C. (pH between 6 and 7). The precipitate thus obtained was collected by filtration and coevaporated with toluene twice to yield 4-hydroxy-1-methyl-1H-indole-2-carboxylic acid (223 mg).

1. customat 0 to 5° C
2. customto give a pH of 9) and
3. stirringstirred for additional 10 minutes
4. customThe aqueous phase was separated
5. customneutralized with 2 N hydrochloric acid at 0° C.
6. customThe precipitate thus obtained
7. filtrationwas collected by filtration