2',5'-Dimethoxycinnamic acid → 6-hydroxy-2H-chromen-2-one

HRID 611694Notes

Reaction equation

HRID 611694 reaction equation
CO[C:3]1[CH:8]=[CH:7][C:6]([O:9]C)=[CH:5][C:4]=1/[CH:11]=[CH:12]/[C:13]([OH:15])=[O:14].Cl.N1C=CC=CC=1>O>[OH:9][C:6]1[CH:5]=[C:4]2[C:3](=[CH:8][CH:7]=1)[O:15][C:13](=[O:14])[CH:12]=[CH:11]2

Participants

4

Reactant 2

HCID 6975942',5'-Dimethoxycinnamic acidHCID 10176127Pyridinium chloride

Product 1

HCID 994776-hydroxy-2H-chromen-2-oneYield 49%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

The carboxylic acid (1.97 g; prepared in reference example 24) and pyridine hydrochloride (12 g) were heated to 180-190° C. The mixture was reacted for 3.5 hr. The reaction mixture was cooled and then dissolved in water. The solution was extracted with ethyl acetate. The extract was washed with water, dried over anhydrous magnesium sulfate and then evaporated. The residue was purified by column chromatography on silica gel (n-hexane:ethyl acetate=3:1→1:1). The obtained crystals were washed with a mixture of n-hexane and ethyl acetate (3:1→1:1) to give the title compound (751 mg) having the following physical data.

Workup

  1. customThe mixture was reacted for 3.5 hr
  2. temperatureThe reaction mixture was cooled
  3. extractionThe solution was extracted with ethyl acetate
  4. washThe extract was washed with water
  5. dry with materialdried over anhydrous magnesium sulfate
  6. customevaporated
  7. customThe residue was purified by column chromatography on silica gel (n-hexane:ethyl acetate=3:1→1:1)
  8. washThe obtained crystals were washed with a mixture of n-hexane and ethyl acetate (3:1→1:1)

Sources & evidence

ORD record
ord-150ce5f0227648b989a98d0a4fa3082f
Source dataset
uspto-grants-1999_12
Patent number
US06001877

Reaction notes

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