Hydrochloric Acid → 5,7-Dihydroxyflavanone

HRID 1949179Notes

Reaction equation

HRID 1949179 reaction equation
[CH:1]1[CH:2]=[CH:3][C:4]([C@H:7]2[O:17][C:16]3[CH:15]=[C:14]([OH:18])[CH:13]=[C:12]([OH:19])[C:11]=3[C:9](=[O:10])[CH2:8]2)=[CH:5][CH:6]=1.Cl.O.CO>CN(C=O)C.[Pd]>[CH2:8]1[C:9](=[O:10])[C:11]2[C:16](=[CH:15][C:14]([OH:18])=[CH:13][C:12]=2[OH:19])[O:17][CH:7]1[C:4]1[CH:3]=[CH:2][CH:1]=[CH:6][CH:5]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 887MethanolHCID 962WaterHCID 68071(+)-Pinocembrin

Product 1

HCID 2387825,7-DihydroxyflavanoneYield 92%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 6228DimethylformamideSolvent

Procedure

4.4 g of the benzyl protected pinocembrin in R-configuration obtained in Example 3 was dissolved in 100 ml of DMF, 20 ml of 10% aqueous HCl and 3.5 g of 10% Pd—C with a water content of 62.9% were added, and then a hydrogenation at normal pressure was performed. The reaction was monitored by TLC until completion (about 5 h). Then stopped stirring, the reaction mixture was filtered and extracted with ethyl acetate and water. The organic phase was collected, evaporated to remove solvent, and recrystallized with 95% ethanol to give a white solid of (S)-pinocembrin (3.0 g, yield 92%) with specific rotation [α]D20=−45.63° (c=0.515, methanol), and e.e %>99.3%.

Workup

  1. customobtained in Example 3
  2. customwas monitored by TLC until completion (about 5 h)
  3. filtrationthe reaction mixture was filtered
  4. extractionextracted with ethyl acetate and water
  5. customThe organic phase was collected
  6. customevaporated
  7. customto remove solvent
  8. customrecrystallized with 95% ethanol

Sources & evidence

ORD record
ord-6b15ba93a5554ec1b129c84a3f53e018
Source dataset
uspto-grants-2013_03
Patent number
US08399691B2

Reaction notes

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