Acetic Anhydride → Chroman

HRID 1374948Notes

Reaction equation

HRID 1374948 reaction equation
O[CH:2]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[O:5][CH2:4][CH2:3]1.C(OC(=O)C)(=O)C.[H][H]>C(O)(=O)C.[Pd]>[O:5]1[C:6]2[C:11](=[CH:10][CH:9]=[CH:8][CH:7]=2)[CH2:2][CH2:3][CH2:4]1

Participants

6

Reactant 3

HCID 7918Acetic AnhydrideHCID 92890Chroman-4-olHCID 178418361HCID 178418361, compound

Product 1

HCID 136319ChromanYield 85.4%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 176Acetic AcidSolvent

Procedure

To a stirred solution of 4-hydroxychroman (10.14 g, 67.5 mmol) in acetic acid (150 mL) under Ar was added acetic anhydride (12.7 mL, 135 mmol) and the mixture was heated at reflux for 3 h, then allowed to cool to ambient temperature. Palladium on carbon (10 wt %; 1.8 g, 2.5 mol %) was added and the mixture was shaken in a Parr hydrogenator under a 42 psi atmosphere of hydrogen overnight. The reaction mixture was filtered, the solvent was removed in vacuo and the residue was taken-up in ethyl acetate. The solution was washed with saturated aqueous sodium bicarbonate solution, brine, dried (magnesium sulfate) and concentrated in vacuo to afford the product (7.73 g, 85%) as a pale yellow liquid: IR νmax (film)/cm−1 2937, 2863, 1737, 1609, 1582, 1490, 1456, 1304, 1267, 1228, 1189, 1116, 1065, 1008 and 754; NMR (400 MHz, CDCl3) δH 2.00 (2H, m), 2.78 (2H, t, J 6.5 Hz), 4.17 (2H, t, J 7 Hz), 6.81 (2H, m) and 7.05 (2H, m).

Workup

  1. temperaturethe mixture was heated
  2. temperatureat reflux for 3 h
  3. filtrationThe reaction mixture was filtered
  4. customthe solvent was removed in vacuo
  5. washThe solution was washed with saturated aqueous sodium bicarbonate solution, brine
  6. dry with materialdried (magnesium sulfate)
  7. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-69e33eaab2aa4203b23d1d59b44ec0fb
Source dataset
uspto-grants-2007_01
Patent number
US07166632B2

Reaction notes

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