Allyl bromide → 5-Methyl-7-(2-propen-1-yloxy)-2H-1-benzopyran-2-one

HRID 1106266Notes

Reaction equation

HRID 1106266 reaction equation
[CH3:1][C:2]1[CH:11]=[C:10]([OH:12])[CH:9]=[C:8]2[C:3]=1[CH:4]=[CH:5][C:6](=[O:13])[O:7]2.C([O-])([O-])=O.[K+].[K+].[CH2:20](Br)[CH:21]=[CH2:22]>>[CH3:1][C:2]1[CH:11]=[C:10]([O:12][CH2:22][CH:21]=[CH2:20])[CH:9]=[C:8]2[C:3]=1[CH:4]=[CH:5][C:6](=[O:13])[O:7]2

Participants

4

Reactant 3

HCID 7841Allyl bromideHCID 11430Potassium Carbonate2×HCID 53556397-hydroxy-5-methylcoumarin

Product 1

HCID 129004425-Methyl-7-(2-propen-1-yloxy)-2H-1-benzopyran-2-one

Procedure

A Me2CO (250 ml) solution of 5-methyl-7-hydroxycoumarin (I; 15.0 g) was reacted with allyl bromide (20 ml) in the presence of K2CO3 (5.0 g) by refluxing the mixture for 5 hours. After chilling the K2CO3 is filtered off and washed with fresh Me2CO. The pooled filtrate and acetonic washings were concentrated to dryness and the residue crystallized from cyclohexane giving 5-methyl-7-allyloxycoumarin (IV; 13.8 g; m.p. 83° ). ##STR7##

Workup

  1. temperatureby refluxing the mixture for 5 hours
  2. filtrationis filtered off
  3. washwashed with fresh Me2CO
  4. concentrationThe pooled filtrate and acetonic washings were concentrated to dryness
  5. customthe residue crystallized from cyclohexane

Sources & evidence

ORD record
ord-2c2741665dd24a78b389915e527ee9d4
Source dataset
uspto-grants-1982_01
Patent number
US04312883

Reaction notes

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