反应详情

温度

10 °C

Preparation of the starting compounds of the formula III using the example of methyl cholanate (Fieset et al., J. Am. Chem. Soc. 74, 1952, 3309) ##STR6## 450 ml of acetyl chloride are slowly added dropwise to 4.5 l of methanol, while cooling with ice, such that the temperature does not exceed 10° to 15° C. After the addition, the mixture is subsequently stirred at about 10° C. for a further 15 minutes. 600 g (1.47 mol) of cholic acid are then introduced at about 5° C. The ice-bath is removed, and after a further hour, while stirring, the reaction is ended. The reaction mixture is slowly added to 12 l of water. The mixture is stirred for a further 2 hours and then filtered with suction, and the residue is rinsed with 3 l of water. The crystalline substance is dried in vacuo at 50° C. 610 g (98%) of methyl cholate (melting point 154° C.) are obtained.

1. temperaturewhile cooling with ice, such that the temperature
2. customdoes not exceed 10° to 15° C
3. additionAfter the addition
4. customThe ice-bath is removed
5. waitafter a further hour
6. stirringwhile stirring
7. additionThe reaction mixture is slowly added to 12 l of water
8. stirringThe mixture is stirred for a further 2 hours
9. filtrationfiltered with suction
10. washthe residue is rinsed with 3 l of water
11. customThe crystalline substance is dried in vacuo at 50° C