Methanol → 3-O-Benzyl-1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranose

HRID 2050660Notes

Reaction equation

HRID 2050660 reaction equation
[O:1]=[CH:2][C@@H:3]([C@H:5]([C@@H:7]([C@@H:9]([CH2:11][OH:12])[OH:10])[OH:8])[OH:6])[OH:4].[CH3:13][C:14]([CH3:16])=O.[CH3:17][C:18]([CH3:20])=O.[H-].[Na+].[CH2:23](Br)[C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1.CO>C1COCC1.[I-].C([N+](CCCC)(CCCC)CCCC)CCC>[CH3:13][C:14]1([CH3:16])[O:4][CH:3]([CH:5]2[O:6][CH:11]3[O:12][C:18]([CH3:20])([CH3:17])[O:10][CH:9]3[CH:7]2[O:8][CH2:23][C:24]2[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=2)[CH2:2][O:1]1

Participants

7

Reactant 4

HCID 887MethanolHCID 7498Benzyl BromideHCID 24758Sodium hydrideHCID 21117658HCID 21117658, compound

Product 1

HCID 979073-O-Benzyl-1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranoseYield 97.1%

Reagents, catalysts & solvents 2

HCID 67553Tetrabutylammonium IodideCatalystHCID 8028TetrahydrofuranSolvent2×

Procedure

A solution of diacetone glucose (5) (Aldrich) (18.0 g, 69.1 mmol) in THF (80 ml) was added dropwise to a stirred suspension of sodium hydride, (50% dispersion in oil, 3.67 g, 76.5 mmol) and tetrabutylammonium iodide (0.2 g, 0.54 mmol) in THF (50 ml) at 0° C. The mixture was warmed to room temperature and benzyl bromide (9.04 ml, 13.0 g, 76.0 mmol) added, then heated to 50° C. for 2 hours. Methanol (20 ml) was added and the mixture stirred for a further 2 hours before cooling, filtering through celite and concentrating. The resulting oil was dissolved in dichloromethane (100 ml), washed with water (2×30 ml), dried, filtered and evaporated to give 3-O-benzyl-1,2:5,6-di-O-isopropylidene-α-D-glucofuranose (23.5 g, 97%) as a pale brown oil. A small quantity was purified by flash chromatography (ethyl acetate-hexane 1:5) to give a clear oil, [α]20D -29.8° (c, 1.06 in chloroform) [lit.43 -27.7° (c, 3.32 in ethanol)]; 1H NMR δ 1.32, 1.39, 1.44, 1.51 (12H, 4×s, 2×acetonide); 3.99-4.11 (5H, m, H-3, H-4, H-5, H-6,6'); 4.59 (1H, d, H-2); 4.59 (1H, d, H-2); 4.65, 4.70 (2H, 2×d, CH2Ph, JH,H' 11.8 Hz); 5.90 (1H, d, H-1, J1,2 3.7 Hz); 7.32-7.36 (5H, m, H-Ph).

Workup

  1. temperatureheated to 50° C. for 2 hours
  2. temperaturebefore cooling
  3. filtrationfiltering through celite
  4. concentrationconcentrating
  5. dissolutionThe resulting oil was dissolved in dichloromethane (100 ml)
  6. washwashed with water (2×30 ml)
  7. customdried
  8. filtrationfiltered
  9. customevaporated

Sources & evidence

ORD record
ord-6218f70c9c984991a017e0bd61af70b7
Source dataset
uspto-grants-1991_05
Patent number
US05013842

Reaction notes

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