反应详情

温度

-78 °C

To 40 ml of tetrahydrofuran were added 1.54 ml (11 m mol) of diisopropylamine and 6.9 ml of 1.6M butyllithium-hexane solution, followed by stirring for 10 minutes under a stream of nitrogen. A solution of 2.43 g of methyl (S)-N-tert-butoxycarbonylpyroglutamate in 15 ml of tetrahydrofuran, was added and stirred for 10 minutes at -78° C. and further for 20 minutes at -40° C. To the reaction mixture which was again cooled to -78° C. was added dropwise a solution of 1.12 ml (11 m mol) of benzaldehyde in 4 ml of tetrahydrofuran. After stirring for 10 minutes, the reaction mixture was diluted with a saturated ammonium chloride solution, stirred until the temperature of the mixture reached room temperature and extracted with ethyl acetate. The combined organic layers were washed with water and then a saturated saline solution, dried over sodium sulfate and distilled to remove the solvent. The residue was subjected to a silica gel column (2.5×40 cm) chromatography (developed by ethyl acetate-hexane=1:3→1:2→1:1) to obtain 2.26 g (65%) of methyl (S)-N-tert-butoxycarbonyl-4-(α-hydroxybenzyl)pyroglutamate as colorless oil.

1. stirringstirred for 10 minutes at -78° C. and further for 20 minutes at -40° C
2. stirringAfter stirring for 10 minutes
3. stirringstirred until the temperature of the mixture
4. customreached room temperature
5. extractionextracted with ethyl acetate
6. washThe combined organic layers were washed with water
7. dry with materiala saturated saline solution, dried over sodium sulfate
8. distillationdistilled
9. customto remove the solvent