Acetic Anhydride → L-Galactose, 6-deoxy-, 2,3,4,5-tetraacetate

HRID 1637414Notes

Reaction equation

HRID 1637414 reaction equation
[O:1]=[CH:2][C@H:3]([C@@H:5]([C@@H:7]([C@H:9]([CH3:11])[OH:10])[OH:8])[OH:6])[OH:4].C(O[C:16](=[O:18])[CH3:17])(=O)C>N1C=CC=CC=1>[C:2]([O:4][C@@H:3]([C@@H:5]([C@@H:7]([C@H:9]([CH3:11])[O:10][C:16](=[O:18])[CH3:17])[O:8][C:9](=[O:10])[CH3:11])[O:6][C:5](=[O:6])[CH3:7])[CH:2]=[O:1])(=[O:1])[CH3:3]

Participants

4

Reactant 2

HCID 7918Acetic AnhydrideHCID 3034656L-(-)-Fucose

Product 1

HCID 14701098L-Galactose, 6-deoxy-, 2,3,4,5-tetraacetateYield 173.9%

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Procedure

To a solution of L-fucose (1.03 g, 6.09 mmol) in 60 mL of pyridine at room temperature is added acetic anhydride (4.6 mL, 4.96 g, 48.7 mmol). The solution is stirred at room temperature for 20 h and concentrated in vacuo. The residue is then dissolved in 50 mL of CH2Cl2 and washed with 5% HCl (4×60 mL), dried over anhydrous Na2SO4 and concentrated to afford 1.76 g (85%) of L-fucose tetraacetate 1 as a white foam, a 5:2 (α:β) mixture of anomers: Rf 0.38 (40% petroleum ether/EtOAc); 1H NMR (CDCl3, 270 MHz, mixture of anomers) δ 6.33 (d, J=2.0 Hz, 1H, H-1α), 5.67 (d, J=8.2 Hz, 1H, H-1β), 5.26-5.38 (m, 5H), 5.06 (dd, J=10.4, 3.4 Hz, 1H, H-3b), 4.27 (q, J=6.6 Hz, 1H, H-5α), 3.95 (q, J=6.3 Hz, 1H, H-5β), 2.23 (s, 3H), 2.19 (s, 3H), 2.18 (s, 3H), 2.17 (s, 3H), 2.15 (s, 3H), 2.04 (s, 3H), 2.02 (s, 3H), 2.01 (s, 3H), 1.22 (d, J=6.6 Hz, 3H, H-6β), 1.16 (d, J=6.6 Hz, 3H, H-6α).

Workup

  1. concentrationconcentrated in vacuo
  2. dissolutionThe residue is then dissolved in 50 mL of CH2Cl2
  3. washwashed with 5% HCl (4×60 mL)
  4. dry with materialdried over anhydrous Na2SO4
  5. concentrationconcentrated

Sources & evidence

ORD record
ord-9abedc28e85249a9b2c8e87eb755931c
Source dataset
uspto-grants-2000_03
Patent number
US06040433

Reaction notes

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