Benzyl Bromide → allyl-3-O-methyl-2,4,6-tri-O-benzyl-glucopyranose

HRID 1781264Notes

Reaction equation

HRID 1781264 reaction equation
[CH2:1]([C:4]1([O:14][C@H:13]([CH2:15][OH:16])[C@@H:11]([OH:12])[C@H:8]([O:9][CH3:10])[C@H:6]1[OH:7])[OH:5])[CH:2]=[CH2:3].[H-].[Na+].[CH2:19](Br)[C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1>CN(C=O)C>[CH2:1]([C:4]1([O:14][C@H:13]([CH2:15][O:16][CH2:19][C:20]2[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=2)[C@@H:11]([O:12][CH2:19][C:20]2[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=2)[C@H:8]([O:9][CH3:10])[C@H:6]1[O:7][CH2:19][C:20]1[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=1)[OH:5])[CH:2]=[CH2:3]

Participants

5

Reactant 3

HCID 7498Benzyl BromideHCID 24758Sodium hydrideHCID 131720021allyl-3-O-methyl-glucopyranose

Product 1

HCID 131720022allyl-3-O-methyl-2,4,6-tri-O-benzyl-glucopyranose

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
0 °C

Procedure

Allyl-3-O-methyl-glucopyranose (4.5 g) was dissolved in anhydrous DMF (120 mL) and sodium hydride (1.84 g, 50% dispersion in oil) was added thereto. The resulting solution was stirred for 0.5 hours at 0° C. Benzyl bromide (6.8 mL) was added dropwise at 0° to 5° C. and the reaction mixture was then stirred for 4 hours at room temperature. The reaction mixture was quenched by adding methanol, diluted with dichloromethane (250 mL) and washed with water (3×250 mL), dried over Na2SO4, filtered and evaporated. The material was purified by chromatography on silica gel using hexane-ethyl acetate (5:1) as eluent. The evaporated fractions from column were crystallized from a mixture of dichloromethane and hexane to provide for allyl-3-O-methyl-2,4,6-tri-O-benzyl-glucopyranose (8 g).

Workup

  1. stirringthe reaction mixture was then stirred for 4 hours at room temperature
  2. customThe reaction mixture was quenched
  3. additionby adding methanol
  4. additiondiluted with dichloromethane (250 mL)
  5. washwashed with water (3×250 mL)
  6. dry with materialdried over Na2SO4
  7. filtrationfiltered
  8. customevaporated
  9. customThe material was purified by chromatography on silica gel
  10. customThe evaporated fractions from column were crystallized from a mixture of dichloromethane and hexane

Sources & evidence

ORD record
ord-a11503481bb24752a1c157037dda3427
Source dataset
uspto-grants-1997_05
Patent number
US05633233

Reaction notes

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