反应详情

10 g of N-(ortho-toluyl)aspartic acid are disolved in 20 ml of methanol in a 500 ml, three-necked, round-bottomed flask equipped with a thermometer, a dropping funnel and a reflux condenser. After having completely dissolved, 28.5 ml of an aqueous sodium hypochlorite solution, assaying at 1.40 mol/l, are added dropwise while maintaining the temperature below 20 °C. At the end of the addition, the mixture is diluted with 180 ml of methanol before being brought to reflux for 1 h 30 minutes. After concentrating under vacuum, the residue is taken up in ethyl acetate and extracted with an aqueous sodium bicarbonate solution. The aqeuous phase is acidified with hydrochloric acid and extracted with ethyl acetate. The organic phase is washed with brine before being dried and concentrated under vacuum to provide an oil which crystallizes on addition of water. The precipitate formed is filtered and purified by recrystallization from water (a few drops of methanol are added, if necessary) to provide 2.65 g of N-(ortho-toluyl) dehydroalanine. (Nonoptimized yield 32%).

1. customthree-necked, round-bottomed flask equipped with a thermometer, a dropping funnel and a reflux condenser
2. dissolutionAfter having completely dissolved
3. additionare added dropwise
4. temperaturewhile maintaining the temperature below 20 °C
5. additionAt the end of the addition
6. temperatureto reflux for 1 h 30 minutes
7. concentrationAfter concentrating under vacuum
8. extractionextracted with an aqueous sodium bicarbonate solution
9. extractionextracted with ethyl acetate
10. washThe organic phase is washed with brine
11. custombefore being dried
12. concentrationconcentrated under vacuum
13. customto provide an oil which
14. customcrystallizes on addition of water
15. customThe precipitate formed
16. filtrationis filtered
17. custompurified by recrystallization from water (a few drops of methanol are added, if necessary)