反应详情

温度

-15 °C

3β-tert-butyldimethylsilyloxy-4,4-dimethyl-5α-chola-8,14-dien-24 oic acid (0.30 g) is dissolved in 10 ml of dry dichloromethane. After cooling to −15° C., 0.07 ml of N-methylmorpholine and 0.084 ml of isobutylchloroformate is added and the mixture is stirred at −15° C. for 20 minutes, whereupon 1.74 ml of a 2.0 M solution of N,N-dimethylamine in THF) is added. The mixture is stirred overnight and the temperature is slowly elevated to room temperature. After aqueous work-up and crystallization from methanol, 3β-tert-butyldimethylsilyloxy-4,4-dimethyl-5α-chola-8,14-dien-24 oic acid-N,N-dimethyl amide (0,231 g) is obtained. M.p. 143-145° C. 1H-NMR (CDCl3, 400 MHz)): δ=5.35 (1H, s); 3.20 (1H, m); 3.03 (3H, s); 2.95 (3H, s); 0.90 (9H, s); 0.05 (6H, m).

1. additionis added
2. customis slowly elevated to room temperature
3. customAfter aqueous work-up and crystallization from methanol