反应详情

19 mmol of the compound from Example 15, 66.7 mmol of KOH, 100 ml of ethanol and 50 ml of water are introduced into a 500 ml single-necked flask fitted with reflux condenser and magnetic stirrer, and the mixture is refluxed for 6 hours. After cooling, the reaction mixture is carefully acidified in concentrated HCl solution and subsequently washed with water until neutral. The solvent is stripped off, and the residue is recrystallized a number of times from glacial acetic acid. The residue is then boiled with methanol and subsequently with ether and filtered off with suction. Yield: 90.5%.

1. customfitted
2. temperaturewith reflux condenser and magnetic stirrer
3. temperaturethe mixture is refluxed for 6 hours
4. temperatureAfter cooling
5. washsubsequently washed with water until neutral
6. customthe residue is recrystallized a number of times from glacial acetic acid
7. filtrationfiltered off with suction