4-Hydroxy-3-isobutyryl-6-isopropyl-pyran-2-one → 4-hydroxy-6-(propan-2-yl)-2H-pyran-2-one

HRID 1988730Notes

Reaction equation

HRID 1988730 reaction equation
[OH:1][C:2]1[CH:7]=[C:6]([CH:8]([CH3:10])[CH3:9])[O:5][C:4](=[O:11])[C:3]=1C(=O)C(C)C>OS(O)(=O)=O>[OH:1][C:2]1[CH:7]=[C:6]([CH:8]([CH3:9])[CH3:10])[O:5][C:4](=[O:11])[CH:3]=1

Participants

3

Reactant 1

HCID 546965914-Hydroxy-3-isobutyryl-6-isopropyl-pyran-2-one

Product 1

HCID 546868844-hydroxy-6-(propan-2-yl)-2H-pyran-2-one

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Conditions

Temperature
0 °C

Procedure

A solution of 4-hydroxy-3-isobutyryl-6-isopropyl-pyran-2-one (10.26 g, 45.8 mmol) in conc. H2SO4 (40 mL) is stirred at 130° C. for 15 min. The dark reaction mixture is then cooled to 0° C., and crushed ice (˜200 g) is added with stirring. The resulting solution is extracted thrice with Et2O, and the combined extracts are dried over Na2SO4 and concentrated. The crude material is purified by flash chromatography on silica gel. Gradient elution with 3:2 hexanes-EtOAc, 1:1 EtOAc-hexanes, 2:1 EtOAc-hexanes, and 3:1 EtOAc-hexanes affords 4-hydroxy-6-isopropyl-pyran-2-one as a light yellow solid. 1H NMR (CDCl3, 300 MHz) δ 11.2 (br, 1H), 6.00 (d, J=1.8 Hz, 1H), 5.58 (d, J=1.8 Hz, 1H), 2.73 (sept, J=6.9 Hz, 1H), 1.22 (d, J=6.9 Hz, 1H) ppm.

Workup

  1. customThe dark reaction mixture
  2. additionis added
  3. extractionThe resulting solution is extracted thrice with Et2O
  4. dry with materialthe combined extracts are dried over Na2SO4
  5. concentrationconcentrated
  6. customThe crude material is purified by flash chromatography on silica gel
  7. washGradient elution with 3:2 hexanes-EtOAc, 1:1 EtOAc-hexanes, 2:1 EtOAc-hexanes, and 3:1 EtOAc-hexanes

Sources & evidence

ORD record
ord-fa1d0395bf684ccda31a19fccf6973d4
Source dataset
uspto-grants-2010_01
Patent number
US07642267B2

Reaction notes

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