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

HRID 1646424Notes

Reaction equation

HRID 1646424 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-a-cetylcoumarinyl)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.). ##STR27##

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-03c9f3e77dd741c59ed1e25616f3d0c3
Source dataset
uspto-grants-1993_01
Patent number
US05179217

Reaction notes

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