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

HRID 490037Notes

Reaction equation

HRID 490037 reaction equation
Br[CH2:2][CH:3]=[CH2:4].[OH:5][C:6]1[CH:15]=[C:14]2[C:9]([C:10]([CH3:17])=[CH:11][C:12](=[O:16])[O:13]2)=[CH:8][CH:7]=1.C(=O)([O-])[O-].[K+].[K+]>CC(C)=O>[CH2:2]([O:5][C:6]1[CH:15]=[C:14]2[C:9]([C:10]([CH3:17])=[CH:11][C:12](=[O:16])[O:13]2)=[CH:8][CH:7]=1)[CH:3]=[CH2:4]

Participants

5

Reactant 3

HCID 7841Allyl bromideHCID 11430Potassium CarbonateHCID 52805674-Methylumbelliferone

Product 1

HCID 2389527-(Allyloxy)-4-methyl-2H-chromen-2-oneYield 96.2%

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

3-Bromo-1-propene (2.95 mL, 34.06 mmol) was added dropwise under argon to a stirred mixture of 7-hydroxy-4-methylcoumarin 1 (2.0 g, 11.35 mmol) and anhydrous potassium carbonate (K2CO3) (2.35 g, 17.03 mmol) in acetone (50 mL). The resulting mixture was then refluxed for 4 h, after which it was allowed to cool, and the K2CO3 filtered off and washed with fresh acetone. The solvent was removed in vacuo and the residue was crystallized from methanol to afford 2 as white-cream crystals (2.36 g, 96%). TLC (hexane/ethyl acetate, 1:3): Rf=0.63. mp 110° C. 1H NMR (CDCl3, 500 MHz) δ 2.39 (s, 3H, CH3), 4.60 (d, J=5.0 Hz, 2H, CH2), 5.33 (d, J=10.5 Hz, 1H), 5.44 (d, J=17.5 Hz, 1H), 6.05 (m, 1H), 6.12 (s, 1H), 6.80 (s, 1H), 6.87 (dd, J=1.5, 9.0 Hz, 1H), 7.49 (d, J=9.0 Hz, 1H). 13C NMR (CDCl3, 125 MHz) δ 18.70, 69.29, 101.84, 112.05, 112.79, 113.75, 118.51, 125.64, 132.31, 152.61, 152.26, 161.26, 161.65. ESIMS calcd for C13H13O3 [M+H]+ 217.1, found 217.1.

Workup

  1. temperatureThe resulting mixture was then refluxed for 4 h
  2. temperatureto cool
  3. filtrationthe K2CO3 filtered off
  4. washwashed with fresh acetone
  5. customThe solvent was removed in vacuo
  6. customthe residue was crystallized from methanol

Sources & evidence

ORD record
ord-64c126458c8142878265339f4570ce1d
Source dataset
uspto-grants-2009_05
Patent number
US07527934B2

Reaction notes

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