4-Hydroxy-6-methyl-2-pyrone → 4-hydroxy-6-methyl-5,6-dihydro-2H-pyran-2-one

HRID 1165751Notes

Reaction equation

HRID 1165751 reaction equation
[OH:1][C:2]1[CH:7]=[C:6]([CH3:8])[O:5][C:4](=[O:9])[CH:3]=1>CO.[Pd]>[OH:1][C:2]1[CH2:7][CH:6]([CH3:8])[O:5][C:4](=[O:9])[CH:3]=1

Participants

4

Reactant 1

HCID 546757574-Hydroxy-6-methyl-2-pyrone

Product 1

HCID 546805364-hydroxy-6-methyl-5,6-dihydro-2H-pyran-2-oneYield 73%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 887MethanolSolvent

Procedure

To a solution of 20.0 g (0.16 mole) of 4-hydroxy-6-methyl-2-pyrone in 250 ml of methanol was added 1.0 g of 5% palladium on carbon as the hydrogenation catalyst. Hydrogenation was carried out at room temperature under a pressure of 20 kg/cm2 for 7 hours. The catalyst was removed by filtration and the solvent was removed by evaporation under a reduced pressure. The precipitated crystal was recovered by filtration and recrystallized from ethanol to obtain 14.8 g (yield: 73%) of 4-hydroxy-5,6-dihydro-6-methyl-2-pyrone in the form of a crystal, m.p. 103°-104° C.

Workup

  1. customThe catalyst was removed by filtration
  2. customthe solvent was removed by evaporation under a reduced pressure
  3. filtrationThe precipitated crystal was recovered by filtration
  4. customrecrystallized from ethanol

Sources & evidence

ORD record
ord-68549ff0af2e47609ae926b11c455b52
Source dataset
uspto-grants-1990_03
Patent number
US04912100

Reaction notes

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