Tetrahydrofuran → Precocene I

HRID 1073395Notes

Reaction equation

HRID 1073395 reaction equation
[CH3:1][O:2][C:3]1[CH:12]=[C:11]2[C:6]([C:7](=O)[CH2:8][C:9]([CH3:14])([CH3:13])[O:10]2)=[CH:5][CH:4]=1.O1CCCC1>[Pd](Cl)Cl.O>[CH3:1][O:2][C:3]1[CH:12]=[C:11]2[C:6]([CH:7]=[CH:8][C:9]([CH3:14])([CH3:13])[O:10]2)=[CH:5][CH:4]=1

Participants

5

Reactant 2

HCID 8028TetrahydrofuranHCID 6056607-methoxy-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-one

Product 1

HCID 28619Precocene IYield 92%

Reagents, catalysts & solvents 2

HCID 24290Palladium ChlorideCatalystHCID 962WaterSolvent

Conditions

Temperature
0 °C

Procedure

A mixture of 2.1 g (10 millimoles) of 7-methoxy-2,2-dimethyl-4-chromanone, 50 ml of tetrahydrofuran, 20 ml of water, 2.66 g (15 millimoles) of palladium chloride and 4.2 g (0.11 mole) of sodium tetrahydro borate is stirred at 0° C for 20 minutes and thereafter at 5° C. for a further 4 hours. The reaction mixture is filtered, the filtrate extracted twice with 50 ml of chloroform each. The solvent is distilled off, the residue taken up in 50 ml of toluene and distilled in the presence of anhydrous potassium hydrogen sulfate for 20 minutes. The reaction having been completed the organic phase is washed twice with 20 ml of water each and the solvent is removed. The crude product is purified by column chromatography. Thus 1.75 g of the desired compound are obtained in the form of a colorless oil, yield 85 %.

Workup

  1. waitat 5° C. for a further 4 hours
  2. filtrationThe reaction mixture is filtered
  3. extractionthe filtrate extracted twice with 50 ml of chloroform each
  4. distillationThe solvent is distilled off
  5. distillationdistilled in the presence of anhydrous potassium hydrogen sulfate for 20 minutes
  6. washis washed twice with 20 ml of water each and the solvent
  7. customis removed
  8. customThe crude product is purified by column chromatography

Sources & evidence

ORD record
ord-d03e997c30c0431fb11d95f0886c2029
Source dataset
uspto-grants-1990_11
Patent number
US04968819

Reaction notes

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