Sulfuric Acid → 6-Bromo-3,4-dihydro-4-phenyl-2H-1-benzopyran-2-one

HRID 745022

Reaction equation

HRID 745022 reaction equation
[CH:1]1[C:6]([OH:7])=[CH:5][CH:4]=[C:3]([Br:8])[CH:2]=1.[C:9](O)(=[O:18])[CH:10]=[CH:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1.S(=O)(=O)(O)O>C(O)(=O)C>[Br:8][C:3]1[CH:4]=[C:5]2[C:6](=[CH:1][CH:2]=1)[O:7][C:9](=[O:18])[CH2:10][CH:11]2[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 78084-BromophenolHCID 87842-Propenoic acid, 3-phenyl-

Product 1

HCID 29249736-Bromo-3,4-dihydro-4-phenyl-2H-1-benzopyran-2-oneYield 55.7%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A solution of p-bromophenol (138 g, 0.8 mole), cinnamic acid (148 g, 1.0 mole), acetic acid (200 g) and conc. sulfuric acid was refluxed for 2 h. Volatile material was distilled at reduced pressure. The residual syrup was cooled and triturated with cold water, giving a semi-crystalline mass. This was washed extensively with water, saturated sodium carbonate and finally with water again. The material was filtered through a sintered glass funnel, and then mixed with an equal weight of ethanol. The slurry was stirred at room temperature for 1 h and then filtered. The resulting product was washed briefly with ethanol and then diisopropyl ether. After drying, 135 g (55.7%) of the title compound was isolated as white crystals, melting at 117° C.

Workup

  1. distillationVolatile material was distilled at reduced pressure
  2. temperatureThe residual syrup was cooled
  3. customtriturated with cold water
  4. customgiving a semi-crystalline mass
  5. washThis was washed extensively with water, saturated sodium carbonate and finally with water again
  6. filtrationThe material was filtered through a sintered glass funnel
  7. additionmixed with an equal weight of ethanol
  8. filtrationfiltered
  9. washThe resulting product was washed briefly with ethanol
  10. customAfter drying

Sources & evidence

ORD record
ord-483456240b074d1cb1f8e70ccd9e4fe9
Source dataset
uspto-grants-1996_09
Patent number
US05559269

Linked notes

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