反应详情

8.4 g (55.4 mm01) of DBU were added dropwise to a solution of 3.3 g (27.7 mmol) of 2-mercaptoisobutyric acid [Can. J. Chem. 61(8), 1872]and 6.9 g (27.7 mmol) of benzyl 2-benzylacrylate (EPA 0117429), whereby the temperature of the reaction mixture was held between 5 and 10°. After completion of the addition the mixture was stirred at 10° for a further 5 hours. Subsequently, the reaction mixture was treated dropwise with 22.5 g (36.6 mmol) of potassium monopersulphate triple salt suspended in 450 ml of water while cooling with ice, whereby the temperature was held below 10°. Thereafter, the mixture was stirred at the same temperature for a further hour, then cooled to 0° and a further 22.5 g (36.6 mmol) of potassium monopersulphate triple salt were added spatula-wise. The mixture was left to warm slowly to room temperature and was stirred for a further 15 hours. For the working-up, the mixture was diluted with 200 ml of water and extracted four times with 60 ml of ethyl acetate each time. The combined organic extracts were dried over sodium sulphate and evaporated under reduced pressure until the product began to crystallize. Then, 30 ml of hexane and 20 ml of ether were added while stirring, the separated product was subsequently filtered off under suction and dried. There were obtained 9.7 g of (RS)-2-[[2-[(benzyloxy)carbonyl]-3-phenylpropyl]sulfonyl]-2-methylpropionic acid as a colourless solid; MS: 422 (M+NH4)+.

1. customwas held between 5 and 10°
2. additionAfter completion of the addition the mixture
3. temperaturewhile cooling with ice, whereby the temperature
4. customwas held below 10°
5. stirringThereafter, the mixture was stirred at the same temperature for a further hour
6. temperaturecooled to 0°
7. waitThe mixture was left
8. stirringwas stirred for a further 15 hours
9. extractionextracted four times with 60 ml of ethyl acetate each time
10. dry with materialThe combined organic extracts were dried over sodium sulphate
11. customevaporated under reduced pressure until the product
12. customto crystallize
13. additionThen, 30 ml of hexane and 20 ml of ether were added
14. stirringwhile stirring
15. filtrationthe separated product was subsequently filtered off under suction
16. customdried