反应详情

There was dissolved 2.054 g (5.0 mmol) of 3-benzylamino-2-(1-hydroxyethyl)-5-trimethylsilyl-4-pentinic acid phenylthioester in 40 ml of THF, to which 3 ml of 4 N potassium hydroxide was added and the mixture was stirred at room temperature for 3 hours. The reaction mixture was neutralized with 2 N hydrochloric acid and was extracted six times with ethyl acetate while conducting salting-out. The extract was dried with anhydrous magnesium sulfate and concentrated. There was added 250 ml of acetonitrile to the concentrated solution, and then 1.57 g (60 mmol) of triphenylphosphine was added, to which 1.32 g (6.0 mmol) of 2,2'-dipyridyldisulfide in 50 ml of acetonitrile was added dropwise for 40 minutes while vigorously stirring with heating under reflux. After the solution was further heated under reflux for 1 hour, the obtained reaction mixture was concentrated, followed by purification with 50 g of silica-gel column-chromatography (eluent; methylene chloride→diethyl ether) and then with 50 g of silica-gel column-chromatography (eluent;hexane:diethyl ether=1:4) to give 801 mg of a trans-form and 62 mg of a cis-form of 1-benzyl-4-ethynyl-3-(1-hydroxyethyl)-2-azetidinone.

1. extractionwas extracted six times with ethyl acetate
2. dry with materialThe extract was dried with anhydrous magnesium sulfate
3. concentrationconcentrated
4. additionThere was added 250 ml of acetonitrile to the concentrated solution
5. additionwas added dropwise for 40 minutes
6. stirringwhile vigorously stirring
7. temperaturewith heating
8. temperatureunder reflux
9. temperatureAfter the solution was further heated
10. temperatureunder reflux for 1 hour
11. customthe obtained reaction mixture
12. concentrationwas concentrated
13. customfollowed by purification with 50 g of silica-gel column-chromatography (eluent; methylene chloride→diethyl ether)