反应详情

A suspension of 103.2 g (0.8 mol) of (L)-pyroglutamic acid in 2.8 liters of toluene, 86.6 g (0.8 mol) of benzyl alcohol and 4.3 ml of sulfuric acid is heated under reflux for 7 to 8 hours in a 4 liter apparatus equipped with a good stirrer and a Dean-Stark attachment. TLC (A) is used to check that the benzyl alcohol has disappeared and the mixture is cooled and washed with 2×400 ml of water, 2×400 ml of a 2% solution of Na2CO3 and then 2×400 ml water. The toluene layer is dried over sodium sulfate and evaporated in vacuo and the residue is dried in vacuo in the presence of P2O5. This gives 70 to 75% of a pure product of Rf=0.5 (A) and melting point=48°-49° C. The product can also be distilled; boiling point=170°-5° C. (0.1 mm Hg).

1. temperatureis heated
2. temperatureunder reflux for 7 to 8 hours in a 4 liter apparatus
3. customequipped with a good stirrer
4. temperaturethe mixture is cooled
5. washwashed with 2×400 ml of water, 2×400 ml of a 2% solution of Na2CO3
6. dry with materialThe toluene layer is dried over sodium sulfate
7. customevaporated in vacuo
8. dry with materialthe residue is dried in vacuo in the presence of P2O5
9. distillationThe product can also be distilled