Trifluoroacetic acid → 5-Bromochroman-3-one

HRID 467078Notes

Reaction equation

HRID 467078 reaction equation
C(OC([CH:6]1[C:15](=[O:16])[CH2:14][C:13]2[C:8](=[CH:9][CH:10]=[CH:11][C:12]=2[Br:17])[O:7]1)=O)C.FC(F)(F)C(O)=O>CO.Cl.O>[Br:17][C:12]1[CH:11]=[CH:10][CH:9]=[C:8]2[C:13]=1[CH2:14][C:15](=[O:16])[CH2:6][O:7]2

Participants

6

Reactant 2

HCID 6422Trifluoroacetic acidHCID 190431932-Ethoxycarbonyl-5-bromo-3-chromanone

Product 1

HCID 190431865-Bromochroman-3-oneYield 53%

Reagents, catalysts & solvents 3

HCID 313Hydrochloric AcidSolventHCID 887MethanolSolventHCID 962WaterSolvent

Procedure

A suspension of 2-ethoxycarbonyl-5-bromo-3-chromanone (300 mg, 1 mMol) in methanol (5 mL) and 10% hydrochloric acid (3 mL) was heated at reflux for 2 hours. All of the solid had not dissolved; therefore, trifluoroacetic acid (1 mL) was added, and heating was continued for 18 hours. The reaction mixture was diluted with water and extracted well with diethyl ether. The ether phases were combined, dried over sodium sulfate, and concentrated in vacuo to give a yellow glass. Purification by flash chromatography (1:1 hexane:ether) gave the title compound as a light yellow glass (120 mg, 53%).

Workup

  1. temperaturewas heated
  2. temperatureat reflux for 2 hours
  3. dissolutionAll of the solid had not dissolved
  4. temperatureheating
  5. extractionextracted well with diethyl ether
  6. dry with materialdried over sodium sulfate
  7. concentrationconcentrated in vacuo
  8. customto give a yellow glass
  9. customPurification by flash chromatography (1:1 hexane:ether)

Sources & evidence

ORD record
ord-42843c29f04f404abe748547c37686fa
Source dataset
uspto-grants-1992_10
Patent number
US05158956

Reaction notes

Loading…