反应详情

温度

10 °C

A mixture that consists of 51.66 g (100 mmol) of 2,3,4,6-tetra-O-pivaloyl-mannopyranose, 0.55 g (5 mmol) of tetramethylammonium chloride and 82.93 g (600 mmol) of fine-powder potassium hydroxide in 350 ml of diethylene glycol dimethyl ether is cooled to 10° C. At 10° C., 35.7 g (150 mmol) of 6-bromohexanoic acid benzyl ester is added in drops within 10 minutes while being stirred vigorously. It is stirred for two hours at 10° C. 250 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 ethanol, mixed with 5 g of palladium (10%) on activated carbon and hydrogenated until hydrogen absorption is completed. Catalyst is filtered out, rewashed with ethanol, and the combined solutions are 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. stirringIt is stirred for two hours at 10° C
2. filtrationsolid is filtered out
3. customthe filtrate is evaporated to the dry state in a vacuum
4. additionmixed with 5 g of palladium (10%) on activated carbon and hydrogenated until hydrogen absorption
5. filtrationCatalyst is filtered out
6. customthe combined solutions are evaporated to the dry state in a vacuum
7. customThe residue is chromatographed on silica gel (mobile solvent: dichloromethane/n=hexane/ethanol/acetic acid=20:5:3:0.5)
8. concentrationThe product-containing fractions are concentrated by evaporation
9. dissolutiondissolved in 400 ml of ethyl acetate
10. stirringshaken out three times with 200 ml of water
11. customThen, the organic phase is separated
12. customevaporated to the dry state in a vacuum