反应详情

1.9 g of sodium cyanoborohydride were added to a solution of 8.85 g of 4-hydroxy-1-N-(β-hydroxyethyl)indole, obtained in the preceding stage, in 40 cm3 of acetic acid, the temperature being maintained below 30° C. After stirring for 30 minutes, the reaction mixture was poured onto 200 g of ice-cold water and the pH was neutralized to 7.5 by addition of 30% aqueous ammonia. The precipitate obtained was filtered off and dried. 7.75 g of 4-hydroxy-1-N-(β-hydroxyethyl)indoline were obtained, the melting point of which was 108° C. 13C and proton nuclear magnetic resonance (N.M.R.) analysis of the product obtained was found to be in accordance with the expected product.

1. temperaturethe temperature being maintained below 30° C
2. customThe precipitate obtained
3. filtrationwas filtered off
4. customdried