Acetic Anhydride → Chroman

HRID 431782Notes

Reaction equation

HRID 431782 reaction equation
[O:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH:4](O)[CH2:3][CH2:2]1.C(OC(=O)C)(=O)C.[H][H]>[Pd].C(O)(=O)C>[O:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH2:4][CH2:3][CH2:2]1

Participants

6

Reactant 3

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

Product 1

HCID 136319ChromanYield 85.1%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 176Acetic AcidSolvent

Procedure

4-Chromanol (Aldrich) (2.77 g, 18.4 mmol) was taken up in acetic anhydride (3.5 ml, 36.9 mmol) and acetic acid (30 ml) and refluxed for 3 h, and then allowed to cool to room temperature over 16 h. 10% w/w Pd/C was then added to the solution and the whole hydrogenated at 40 p.s.i. hydrogen pressure for 16 h. The catalyst was filtered through a pad of Arbocel and the filtrate evaporated to low (5 ml) volume. The remaining liquid was dissolved in EtOAc (30 ml) and washed with water, then NaHCO3 solution (100 ml of each). The organic layer was dried over MgSO4 and evaporated to a pale yellow oil. This oil was columned in 10% EtOAc/pentane to give the title product (2.1 g, 85%); 1HNMR (400 MHz, CDCl3) δ: 1.93-2.04 (m, 2H), 2.79 (t, 2H), 4.18 (t, 2H), 6.78-6.83 (m, 2H), 7.00-7.10 (m, 2H).

Workup

  1. filtrationThe catalyst was filtered through a pad of Arbocel
  2. customthe filtrate evaporated to low (5 ml) volume
  3. dissolutionThe remaining liquid was dissolved in EtOAc (30 ml)
  4. washwashed with water
  5. dry with materialThe organic layer was dried over MgSO4
  6. customevaporated to a pale yellow oil

Sources & evidence

ORD record
ord-5a38ac0fd7ad470eb4de91acdb38e8a7
Source dataset
uspto-grants-2003_12
Patent number
US06660756B2

Reaction notes

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