Allyl bromide → 7-(Allyloxy)-4-methyl-2H-chromen-2-one

HRID 848152Notes

Reaction equation

HRID 848152 reaction equation
[OH:1][C:2]1[CH:11]=[C:10]2[C:5]([C:6]([CH3:13])=[CH:7][C:8](=[O:12])[O:9]2)=[CH:4][CH:3]=1.C([O-])([O-])=O.[K+].[K+].[CH2:20](Br)[CH:21]=[CH2:22]>CC(C)=O>[CH2:22]([O:1][C:2]1[CH:11]=[C:10]2[C:5]([C:6]([CH3:13])=[CH:7][C:8](=[O:12])[O:9]2)=[CH:4][CH:3]=1)[CH:21]=[CH2:20]

Participants

5

Reactant 3

HCID 7841Allyl bromideHCID 11430Potassium CarbonateHCID 52805674-Methylumbelliferone

Product 1

HCID 2389527-(Allyloxy)-4-methyl-2H-chromen-2-oneYield 98.1%

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

7-Hydroxy-4-methylcoumarin (70.00 g, 0.397 mol), anhydrous K2CO3 (140 g, 1.01 mol), and allyl bromide (100 ml, 1.15 mol) were added to 2.0 L of reagent grade acetone. The milky mixture was refluxed for sixteen hours with overhead stirring, allowed to cool to room temperature, and filtered. Solids were washed once with reagent grade acetone (150 ml.), the filtrate and wash combined, and the resulting combined filtrate concentrated to dryness with a rotary evaporator to obtain 7-allyloxy-4-methylcoumarin (84.2 g, 98% yield). The crude product melted at 100.0°-101.5° C. (lit. 1 101° C.), showed only one spot in TLC, and was used in the next step.

Workup

  1. temperatureThe milky mixture was refluxed for sixteen hours with overhead stirring
  2. filtrationfiltered
  3. washSolids were washed once with reagent grade acetone (150 ml.)
  4. washthe filtrate and wash
  5. concentrationconcentrated to dryness with a rotary evaporator

Sources & evidence

ORD record
ord-a70b5fbf8043442ba20665c18fed52ef
Source dataset
uspto-grants-1981_10
Patent number
US04294847

Reaction notes

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