Potassium Hydroxide → 2,3,4,6-Tetra-O-benzyl-1-O-(1-hydroxy-eth-2-yl)-mannopyranose

HRID 1265308Notes

Reaction equation

HRID 1265308 reaction equation
[CH2:1]([O:8][C@H:9]1[C@@H:15]([O:16][CH2:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)[C@H:14]([O:24][CH2:25][C:26]2[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=2)[C@@H:13]([CH2:32][O:33][CH2:34][C:35]2[CH:40]=[CH:39][CH:38]=[CH:37][CH:36]=2)[O:12][CH:10]1[OH:11])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[OH-].[K+].Br[CH2:44][CH2:45][O:46]C(=O)C(C)(C)C>S([O-])(O)(=O)=O.C([N+](CCCC)(CCCC)CCCC)CCC.C1C=CC=CC=1>[CH2:1]([O:8][C@H:9]1[C@@H:15]([O:16][CH2:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)[C@H:14]([O:24][CH2:25][C:26]2[CH:27]=[CH:28][CH:29]=[CH:30][CH:31]=2)[C@@H:13]([CH2:32][O:33][CH2:34][C:35]2[CH:36]=[CH:37][CH:38]=[CH:39][CH:40]=2)[O:12][CH:10]1[O:11][CH2:44][CH2:45][OH:46])[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1

Participants

6

Reactant 3

HCID 14797Potassium HydroxideHCID 110169932,3,4,6-Tetra-O-benzyl-D-mannopyranoseHCID 145722042-Bromoethyl 2,2-dimethylpropanoate

Product 1

HCID 101449962,3,4,6-Tetra-O-benzyl-1-O-(1-hydroxy-eth-2-yl)-mannopyranose

Reagents, catalysts & solvents 2

HCID 94433Tetrabutylammonium hydrogen sulfateCatalystHCID 241BenzeneSolvent2×

Conditions

Temperature
0 °C

Procedure

A mixture that consists of 54.1 g (100 mmol) of 2,3,4,6-tetra-O-benzyl-mannopyranose, 1.7 g (5 mmol) of tetrabutylammonium hydrogen sulfate and 33.7 g (600 mmol) of fine-powder potassium hydroxide in 350 ml of benzene is cooled to 0° C. At 0° C., 31.4 g (150 mmol) of 2,2-dimethyl-propionic acid-bromoethylester is added in drops over 30 minutes while being stirred vigorously. It is stirred for two hours at 0° C. 300 ml of benzene 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/100 ml of water. 100 ml of 50% aqueous potassium hydroxide solution is added, and it is refluxed for eight hours. It is cooled to 0° C., set at pH 8 with 10% aqueous hydrochloric acid, and then the solvent is distilled off (vacuum). The residue is taken up in 300 ml of water and 400 ml of ethyl acetate, and the pH of the aqueous phase is set at 5 while being stirred (10% aqueous hydrochloric acid). The organic phase is separated, and the aqueous phase is extracted once more with 200 ml of ethyl acetate. The combined organic phases are dried on magnesium sulfate, the solvent is distilled off in a vacuum, and the residue is chromatographed on silica gel (mobile solvent: dichloromethane/nhexane/ethanol=20:8:2). The product-containing fractions are concentrated by evaporation.

Workup

  1. stirringIt is stirred for two hours at 0° C
  2. filtrationsolid is filtered out
  3. customthe filtrate is evaporated to the dry state in a vacuum
  4. addition100 ml of 50% aqueous potassium hydroxide solution is added
  5. temperatureit is refluxed for eight hours
  6. temperatureIt is cooled to 0° C.
  7. distillationthe solvent is distilled off (vacuum)
  8. stirringwhile being stirred (10% aqueous hydrochloric acid)
  9. customThe organic phase is separated
  10. extractionthe aqueous phase is extracted once more with 200 ml of ethyl acetate
  11. customThe combined organic phases are dried on magnesium sulfate
  12. distillationthe solvent is distilled off in a vacuum
  13. customthe residue is chromatographed on silica gel (mobile solvent: dichloromethane/nhexane/ethanol=20:8:2)
  14. concentrationThe product-containing fractions are concentrated by evaporation

Sources & evidence

ORD record
ord-05327fa4cf614881bb73538299cea784
Source dataset
uspto-grants-2003_04
Patent number
US06545135B2

Reaction notes

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