反应详情

温度

0 °C

A mixture that consists of 34.83 g (100 mmol) of 2,3,4,6-tetra-O-acetyl-glucopyranose, 1.39 g (5 mmol) of tetrabutylammonium chloride and 15.22 g (100 mmol) of DBU in 300 ml of tetrahydrofuran is cooled to 0° C. At 0° C., 34.36 g (150 mmol) of 2-bromoacetic acid benzyl ester, dissolved in 40 ml of tetrahydrofuran, is added in drops over 30 minutes while being stirred vigorously. It is stirred for three hours at 0° C. 300 ml of MTB (methyl-tert-butyl ether) is added, solid is filtered out, and the filtrate is evaporated to the dry state in a vacuum. The residue is taken up in 500 ml of tetrahydrofuran. 5 g of palladium (10%) on activated carbon is added thereto and hydrogenated until hydrogen absorption is completed. Then, catalyst is filtered out, it is rewashed with a little tetrahydrofuran and evaporated to the dry state in a vacuum. The residue is chromatographed on silica gel (mobile solvent: dichloromethane/n=hexane/ethanol/acetic acid=20:5:3:0.5). The product-containing fractions are concentrated by evaporation, dissolved in 400 ml of ethyl acetate and shaken out three times with 200 ml of water. Then, the organic phase is separated and evaporated to the dry state in a vacuum.

1. additionis added in drops over 30 minutes
2. stirringIt is stirred for three hours at 0° C
3. filtrationsolid is filtered out
4. customthe filtrate is evaporated to the dry state in a vacuum
5. addition5 g of palladium (10%) on activated carbon is added
6. customhydrogenated until hydrogen absorption
7. filtrationThen, catalyst is filtered out
8. customevaporated to the dry state in a vacuum
9. customThe residue is chromatographed on silica gel (mobile solvent: dichloromethane/n=hexane/ethanol/acetic acid=20:5:3:0.5)
10. concentrationThe product-containing fractions are concentrated by evaporation
11. dissolutiondissolved in 400 ml of ethyl acetate
12. stirringshaken out three times with 200 ml of water
13. customThen, the organic phase is separated
14. customevaporated to the dry state in a vacuum