Kojic Acid → 5-(5-Bromopentyloxy)-2-(hydroxymethyl)-4H-pyran-4-one

HRID 2108851Notes

Reaction equation

HRID 2108851 reaction equation
[CH:1]1[C:6](=[O:7])[C:5]([OH:8])=[CH:4][O:3][C:2]=1[CH2:9][OH:10].C([O-])([O-])=O.[Cs+].[Cs+].[Br:17][CH2:18][CH2:19][CH2:20][CH2:21][CH2:22]Br>CN(C=O)C>[Br:17][CH2:18][CH2:19][CH2:20][CH2:21][CH2:22][O:8][C:5]1[C:6](=[O:7])[CH:1]=[C:2]([CH2:9][OH:10])[O:3][CH:4]=1

Participants

5

Reactant 3

HCID 3840Kojic AcidHCID 81001,5-DibromopentaneHCID 10796Cesium carbonate

Product 1

HCID 179758375-(5-Bromopentyloxy)-2-(hydroxymethyl)-4H-pyran-4-oneYield 46.3%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Conditions

Temperature
110 °C

Procedure

Kojic acid (2 g, 14.1 mmol), Cs2CO3 (4.6 g, 14.1 mmol) and DMF (12 mL) were charged in a 100 ml round-bottomed flask equipped with a magnetic stirrer. 1,5-Dibromopentane (8.1 g, 35.2 mmol) was added and the reaction mixture was stirred for 2 h at 110° C. After evaporation of DMF, the reaction mixture was poured in 50 mL of H2O, extracted with CH2Cl2 (2×100 mL). The organic layer was washed with brine (2×20 mL), dried over MgSO4, filtered and evaporated to dryness. The crude compound was purified by column chromatography (SiO2; CH2Cl2:MeOH 99:1 to 95:5) to give after evaporation 5-(5-bromopentyloxy)-2-(hydroxymethyl)-4H-pyran-4-one 10 (1.9 g, 46% yield) as a brown oil.

Workup

  1. customequipped with a magnetic stirrer
  2. customAfter evaporation of DMF
  3. additionthe reaction mixture was poured in 50 mL of H2O
  4. extractionextracted with CH2Cl2 (2×100 mL)
  5. washThe organic layer was washed with brine (2×20 mL)
  6. dry with materialdried over MgSO4
  7. filtrationfiltered
  8. customevaporated to dryness
  9. customThe crude compound was purified by column chromatography (SiO2; CH2Cl2:MeOH 99:1 to 95:5)
  10. customto give

Sources & evidence

ORD record
ord-cf9495e78e1846babbf77ca24ae5279d
Source dataset
uspto-grants-2009_04
Patent number
US07514432B2

Reaction notes

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