p-Toluenesulfonic acid → (RS)-2-(2-buten-1-yl)-7-methoxy-4-chromanone

HRID 264529Notes

Reaction equation

HRID 264529 reaction equation
[CH3:1][O:2][C:3]1[CH:12]=[C:11]2[C:6]([C:7](=[O:13])[CH2:8][CH2:9][O:10]2)=[CH:5][CH:4]=1.[CH3:14][CH:15](O)[CH:16]=[CH2:17].C1(C)C=CC(S(O)(=O)=O)=CC=1>COC(OC)(C)C.C1(C)C=CC=CC=1>[CH2:14]([CH:9]1[CH2:8][C:7](=[O:13])[C:6]2[C:11](=[CH:12][C:3]([O:2][CH3:1])=[CH:4][CH:5]=2)[O:10]1)[CH:15]=[CH:16][CH3:17]

Participants

6

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 117163-Buten-2-olHCID 43875107-methoxy-3,4-dihydro-2H-1-benzopyran-4-one

Product 1

HCID 54266277(RS)-2-(2-buten-1-yl)-7-methoxy-4-chromanoneYield 41%

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 64952,2-DimethoxypropaneSolvent

Procedure

A solution 11.9 g of 7-methoxy-4-chromanone, 13.8 ml of 3-buten-2-ol and 120 mg of p-toluenesulfonic acid in 14 ml of 2,2-dimethoxypropane and 120 ml of anhydrous toluene was boiled under reflux for 24 hours. The reaction mixture was subsequently concentrated in a vacuum and purified by column chromatography on silica gel (hexane/diethyl ether 4:1). 6.3 g (41%) of (RS)-2-(2-buten-1-yl)-7-methoxy-4-chromanone were obtained as a yellow oil.

Workup

  1. temperatureunder reflux for 24 hours
  2. concentrationThe reaction mixture was subsequently concentrated in a vacuum
  3. custompurified by column chromatography on silica gel (hexane/diethyl ether 4:1)

Sources & evidence

ORD record
ord-a9f34ce413594d0ea472548bb4df2f61
Source dataset
uspto-grants-1997_07
Patent number
US05646173

Reaction notes

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