Acetic Anhydride → 6-Methyl-2-oxo-2H-1-benzopyran-7-yl acetate

HRID 359502Notes

Reaction equation

HRID 359502 reaction equation
[CH3:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][C:11]=1[OH:12])[O:8][C:7](=[O:13])[CH:6]=[CH:5]2.[C:14](OC(=O)C)(=[O:16])[CH3:15].C(O[Na])(C)=O>O>[CH3:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][C:11]=1[O:12][C:14](=[O:16])[CH3:15])[O:8][C:7](=[O:13])[CH:6]=[CH:5]2

Participants

5

Reactant 3

HCID 7918Acetic AnhydrideHCID 54129132H-1-Benzopyran-2-one, 7-hydroxy-6-methyl-HCID 178418247HCID 178418247, compound

Product 1

HCID 132989326-Methyl-2-oxo-2H-1-benzopyran-7-yl acetate

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Procedure

To prepare the alkylangelicins with an alkyl group in the 4'-position of the furan ring, the suitable umbelliferones, (I), (II), (III) were acetylated and the 7-acetoxycoumarins thus obtained were submitted to the Fries rearrangement. The 8-acetylumbelliferones were converted into the ethyl esters of the 7-(8-acetylcoumarinyl)oxyacetic acids, which were then hydrolized and cyclized yielding the desired 4'-methylangelicins. In such a manner a mixture of 6-methyl-7-hydroxycoumarin (I) (10.0 g), acetic anhydride (40 ml) and anhydrous AcONa (4.0 g) was refluxed for 1 h. To the reaction mixture an equal volume of H2O was cautiously added and the whole was refluxed for 10 min. The mixture was diluted with H2O (300 ml), chilled and the precipitate was collected by filtration, washed several times with H2O, dried and crystallized from MeOH, yielding the 6-methyl-7-acetoxycoumarin (XXII) (10.0 g; m.p. 147° C.). ##STR28##

Workup

  1. customhydrolized and cyclized yielding the desired 4'-methylangelicins
  2. temperaturewas refluxed for 1 h
  3. temperaturethe whole was refluxed for 10 min
  4. temperaturechilled
  5. filtrationthe precipitate was collected by filtration
  6. washwashed several times with H2O
  7. customdried
  8. customcrystallized from MeOH

Sources & evidence

ORD record
ord-06eb8eaed64346a996d272bbc2cd30f9
Source dataset
uspto-grants-1991_03
Patent number
US05001147

Reaction notes

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