Sulfuric Acid → 2,3,4,6-Tetra-O-benzyl-D-mannopyranose

HRID 522176Notes

Reaction equation

HRID 522176 reaction equation
[CH2:1]([O:8][C@H:9]1[C@H:14]([O:15][CH2:16][C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)[C@H:13]([O:23][CH2:24][C:25]2[CH:30]=[CH:29][CH:28]=[CH:27][CH:26]=2)[C@@H:12]([O:31]C)[O:11][C@@H:10]1[CH2:33][O:34][CH2:35][C:36]1[CH:41]=[CH:40][CH:39]=[CH:38][CH:37]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.OS(O)(=O)=O.C(=O)([O-])[O-].[K+].[K+]>C(O)(=O)C>[CH2:24]([O:23][C@H:13]1[C@@H:14]([O:15][CH2:16][C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)[C@H:9]([O:8][CH2:1][C:2]2[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=2)[C@@H:10]([CH2:33][O:34][CH2:35][C:36]2[CH:37]=[CH:38][CH:39]=[CH:40][CH:41]=2)[O:11][CH:12]1[OH:31])[C:25]1[CH:30]=[CH:29][CH:28]=[CH:27][CH:26]=1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 11430Potassium CarbonateHCID 10840492Methyl 2,3,4,6-Tetra-O-benzyl-a-D-mannopyranoside

Product 1

HCID 110169932,3,4,6-Tetra-O-benzyl-D-mannopyranoseYield 54.9%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Conditions

Temperature
80 °C

Procedure

To a solution of (2R,3R,4S,5S,6S)-3,4,5-tris(benzyloxy)-2-((benzyloxy)methyl)-6-methoxytetrahydro-2H-pyran (28.0 g, 50.5 mmol, 1.0 equiv) in acetic acid (480 mL), was added 3M H2SO4 (120 mL, aqueous) at 0° C. The reaction was heated at 80° C. for 10 hours, cooled to room temperature, and then neutralized with saturated aqueous potassium carbonate solution. The mixture was then extracted with DCM (3×1000 mL). The combined organic layers were dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo. The material thus obtained was purified by silica gel chromatography, eluting with 30% EtOAc in petroleum ether, to give (3S,4S,5R,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran-2-ol as a pale yellow oil (15.0 g, 54%). 1H NMR (300 MHz, DMSO-d6) δ 7.38-7.17 (m, 20H), 6.61 (d, J=4.4 Hz, 1H), 5.14-5.07 (m, 1H), 4.77 (t, J=8.5 Hz, 3H), 4.71-4.38 (m, 6H), 3.80 (dp, J=22.8, 9.1, 8.3 Hz, 3H), 3.68-3.53 (m, 2H). ESI (M+H2O) 558.2; calc for C34H36O6 540.3.

Workup

  1. temperaturecooled to room temperature
  2. extractionThe mixture was then extracted with DCM (3×1000 mL)
  3. dry with materialThe combined organic layers were dried over anhydrous sodium sulfate
  4. filtrationfiltered
  5. concentrationconcentrated in vacuo
  6. customThe material thus obtained
  7. customwas purified by silica gel chromatography
  8. washeluting with 30% EtOAc in petroleum ether

Sources & evidence

ORD record
ord-000bb1af68e64784be6395c2c2aa3d82
Source dataset
uspto-grants-2016_05
Patent number
US09328134B2

Reaction notes

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