Methyl iodide → 7-Hydroxy-5-methoxy-4-methyl-2H-1-benzopyran-2-one

HRID 1106270Notes

Reaction equation

HRID 1106270 reaction equation
[CH3:1][C:2]1[C:11]2[C:6](=[CH:7][C:8]([O:16]C(=O)C)=[CH:9][C:10]=2[O:12][C:13](=O)C)[O:5][C:4](=[O:20])[CH:3]=1.C([O-])([O-])=O.[K+].[K+].CI>C(COC)OC>[CH3:1][C:2]1[C:11]2[C:6](=[CH:7][C:8]([OH:16])=[CH:9][C:10]=2[O:12][CH3:13])[O:5][C:4](=[O:20])[CH:3]=1

Participants

5

Reactant 3

HCID 6328Methyl iodideHCID 11430Potassium CarbonateHCID 390800NSC688796

Product 1

HCID 129004537-Hydroxy-5-methoxy-4-methyl-2H-1-benzopyran-2-one

Reagents, catalysts & solvents 1

HCID 80711,2-DimethoxyethaneSolvent

Procedure

The 4-methyl-5,7-diacetoxycoumarin (XXXIV) was dissolved in dimethoxyethane (80 ml) and a solution of dry K2CO3 (6.6 g) and methyl iodide (3 ml) was added. The mixture was refluxed for 6 h, the solvent was evaporated and the residue, after addition of water:methanol (50:50; 80 ml), was heated to reflux 20 min. By evaporation of the MeOH under reduced pressure and by cooling a precipitate was formed, which by crystallization of first from MeOH and then from Me2CO gave 4-methyl-5-methoxy-7-hydroxycoumarin (XXXV; 1.52 g; m.p. 261°-3° C.). ##STR38##

Workup

  1. temperatureThe mixture was refluxed for 6 h
  2. customthe solvent was evaporated
  3. additionthe residue, after addition of water:methanol (50:50; 80 ml)
  4. temperaturewas heated
  5. temperatureto reflux 20 min
  6. customBy evaporation of the MeOH under reduced pressure
  7. temperatureby cooling a precipitate
  8. customwas formed
  9. customwhich by crystallization of first from MeOH

Sources & evidence

ORD record
ord-9b0eb55499464c3893860e0c4697247c
Source dataset
uspto-grants-1982_01
Patent number
US04312883

Reaction notes

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