Hydrogen Bromide → 6-Hydroxy-chroman-4-one

HRID 1109767Notes

Reaction equation

HRID 1109767 reaction equation
C[O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[O:9][CH2:8][CH2:7][C:6]2=[O:13].Br>C(O)(=O)C>[OH:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[O:9][CH2:8][CH2:7][C:6]2=[O:13]

Participants

4

Reactant 2

HCID 260Hydrogen BromideHCID 46121686-methoxy-3,4-dihydro-2H-1-benzopyran-4-one

Product 1

HCID 70989446-Hydroxy-chroman-4-oneYield 14.3%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A mixture of 36 g of 6-methoxychroman-4-one and 290 ml of 48% hydrogen bromide solution in 290 ml of glacial acetic acid was heated to reflux for 3 hours. The solvent was removed in vacuo and the residue diluted with 2 l of water and stored in a refrigerator overnight. The resulting solid was filtered, washed with water and dried, 25.7 g. The original filtrate was extracted with ethyl acetate and the organic layer dried over sodium sulfate and concentrated to give an additional 4.75 g of the titled product.

Workup

  1. temperaturewas heated
  2. temperatureto reflux for 3 hours
  3. customThe solvent was removed in vacuo
  4. additionthe residue diluted with 2 l of water
  5. customstored in a refrigerator overnight
  6. filtrationThe resulting solid was filtered
  7. washwashed with water
  8. customdried
  9. extractionThe original filtrate was extracted with ethyl acetate
  10. dry with materialthe organic layer dried over sodium sulfate
  11. concentrationconcentrated

Sources & evidence

ORD record
ord-70d493d124104cef9d38d04ac7d6e131
Source dataset
uspto-grants-1994_06
Patent number
US05322847

Reaction notes

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