反应详情

温度

45 °C

Glutamic acid (20 g, 0.14 mol, 1 equiv), BnOH (21.1 mls, 0.20 moles, 1.5 equiv) were dissolved in of toluene (30 ml) with stirring in a three necked RB flask. To the resultant mixture methanesulphonic acid (10.6 ml, 0.16 mol, 1.2 equiv) was added slowly whilst maintaining the temperature of the mixture at 45° C. Stirring was continued at this temperature for 2 hrs following which the mixture was cooled to 30° C. and stirred for an additional 4 hrs. Water (50 ml) was then added to the mixture and the organic phase was separated. To the aqueous phase ethanol (30 ml) was added followed by cold aq. ammonia to obtain a pH of 6.5-7. At this point a thick white precipitate was formed which could either be heated to 60° C. and stirred for 2 hrs to improve the crystallinity and then cooled to 5-10° C. or filtered at this point and washed with ethanol (2×20 ml) and water (3×20 ml). The product is then allowed to dry and used without further purification (3.45 g, 21%).

1. stirringStirring
2. temperaturewas cooled to 30° C.
3. stirringstirred for an additional 4 hrs
4. customthe organic phase was separated
5. additionTo the aqueous phase ethanol (30 ml) was added
6. customto obtain a pH of 6.5-7
7. customAt this point a thick white precipitate was formed which
8. temperaturecould either be heated to 60° C.
9. stirringstirred for 2 hrs
10. temperaturecooled to 5-10° C.
11. filtrationfiltered at this point
12. washwashed with ethanol (2×20 ml) and water (3×20 ml)
13. customto dry
14. customused without further purification (3.45 g, 21%)