反应详情

温度

14 °C

7.99 g of sodium cyanoborohydride are gradually added to a solution of 8.90 g of 4-bromo-2-methylindole (which can be prepared according to patent US2010/160647 A1, 2010) in 310 ml of acetic acid under argon cooled to a temperature of about 14° C. The reaction mixture is stirred at a temperature of about 14° C. for 15 minutes, and it is then allowed to warm up to ambient temperature. After 2 hours, the reaction mixture is poured into an Erlenmeyer flask containing ice-cold water (200 ml) and then the pH is brought to 9 with an aqueous ammonia solution. The reaction medium is extracted with dichloromethane (2×200 ml) and then the organic phases are combined, washed with water, dried over magnesium sulfate, filtered, and then concentrated to dryness under reduced pressure. After purification of the residue by silica column chromatography, elution being carried out with a mixture of heptane and ethyl acetate (90/10), 5.92 g of 4-bromo-2-methylindoline are obtained, the characteristics of which are the following:

1. temperatureto warm up to ambient temperature
2. waitAfter 2 hours
3. additionthe reaction mixture is poured into an Erlenmeyer flask
4. extractionThe reaction medium is extracted with dichloromethane (2×200 ml)
5. washwashed with water
6. dry with materialdried over magnesium sulfate
7. filtrationfiltered
8. concentrationconcentrated to dryness under reduced pressure
9. customAfter purification of the residue
10. washby silica column chromatography, elution
11. additionbeing carried out with a mixture of heptane and ethyl acetate (90/10), 5.92 g of 4-bromo-2-methylindoline
12. customare obtained