Boron trifluoride etherate → 4-Hydroxy-3-(1-phenylbutyl)-2H-1-benzopyran-2-one

HRID 2293662Notes

Reaction equation

HRID 2293662 reaction equation
[OH:1][C:2]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[O:5][C:4](=[O:12])[CH:3]=1.[C:13]1([CH:19](O)[CH2:20][CH2:21][CH3:22])[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1.B(F)(F)F.CCOCC>O1CCOCC1>[OH:1][C:2]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[O:5][C:4](=[O:12])[C:3]=1[CH:19]([C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1)[CH2:20][CH2:21][CH3:22]

Participants

5

Reactant 3

HCID 8000Boron trifluoride etherateHCID 953721-Phenyl-1-butanolHCID 546829304-Hydroxycoumarin

Product 1

HCID 547115604-Hydroxy-3-(1-phenylbutyl)-2H-1-benzopyran-2-oneYield 12.7%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

To a mixture of 792 mg of 4-hydroxycoumarin and 809 mg of 1-phenyl- 1 -butanol of Preparation 12 in 25 mL of dioxane under an argon atmosphere is added 2.6 mL of boron trifluoride etherate. The resulting yellow solution is left to stir at room temperature overnight. The volatiles are removed under reduced pressure and the residue is partioned between diethyl ether and 1N sodium hydroxide. The basic aqueous phase is washed with diethyl ether, acidified to pH=1 with 6N hydrochloric acid. The resulting precipitant is repeatedly extracted with dichloromethane (methanol-chloroform co-solvents). The combined dichloromethane extracts are washed once with dilute sodium bicarbonate to remove most of the unreacted 4-hydroxycoumarin, then brine, dried (magnesium sulfate), and finally concentrated under reduced pressure. The residue is adsorbed onto silica and flash column chromatographed with 40% to 50% ethyl acetate in hexane to yield 183 mg of the title product as white crystals.

Workup

  1. waitThe resulting yellow solution is left
  2. customThe volatiles are removed under reduced pressure
  3. washThe basic aqueous phase is washed with diethyl ether
  4. extractionThe resulting precipitant is repeatedly extracted with dichloromethane (methanol-chloroform co-solvents)
  5. washThe combined dichloromethane extracts are washed once with dilute sodium bicarbonate
  6. customto remove most of the unreacted 4-hydroxycoumarin
  7. dry with materialbrine, dried (magnesium sulfate)
  8. concentrationfinally concentrated under reduced pressure
  9. customchromatographed with 40% to 50% ethyl acetate in hexane

Sources & evidence

ORD record
ord-81bd18bd06d64a4ca1f4395f16a8472b
Source dataset
uspto-grants-1997_11
Patent number
US05686486

Reaction notes

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