Allyl bromide → 2H-1-Benzopyran-2-one, 4,8-dimethyl-7-(2-propen-1-yloxy)-

HRID 2287166Notes

Reaction equation

HRID 2287166 reaction equation
[OH:1][C:2]1[C:11]([CH3:12])=[C:10]2[C:5]([C:6]([CH3:14])=[CH:7][C:8](=[O:13])[O:9]2)=[CH:4][CH:3]=1.C([O-])([O-])=O.[K+].[K+].[CH2:21](Br)[CH:22]=[CH2:23]>CC(C)=O>[CH2:23]([O:1][C:2]1[C:11]([CH3:12])=[C:10]2[C:5]([C:6]([CH3:14])=[CH:7][C:8](=[O:13])[O:9]2)=[CH:4][CH:3]=1)[CH:22]=[CH2:21]

Participants

5

Reactant 3

HCID 7841Allyl bromideHCID 11430Potassium CarbonateHCID 53565972H-1-Benzopyran-2-one, 7-hydroxy-4,8-dimethyl-

Product 1

HCID 962252H-1-Benzopyran-2-one, 4,8-dimethyl-7-(2-propen-1-yloxy)-Yield 103%

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

7-Hydroxy-4,8-dimethylcoumarin (91.075 g, 0.479 mol), anhydrous K2CO3 (302.9 g, 2.190 mol), and allyl bromide (217.1 mL, 2.51 mol) were added to 2.5 L of reagent grade acetone. The milky mixture was refluxed for eight hours with overhead stirring, filtered, and the filtrate was concentrated to dryness with the rotary evaporator to obtain 7-allyloxy-4,8-dimethylcoumarin (113.5 g, 0.493 mol, 103%). The crude product melted at 94.0°-100° C. (lit. mp 108° C.) and was used in the next step.

Workup

  1. temperatureThe milky mixture was refluxed for eight hours with overhead stirring
  2. filtrationfiltered
  3. concentrationthe filtrate was concentrated to dryness with the rotary evaporator

Sources & evidence

ORD record
ord-44521be94499426bab3e09f14a8fe8a1
Source dataset
uspto-grants-1981_05
Patent number
US04269851

Reaction notes

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