Hydrochloric Acid → (R)-Pinocembrin

HRID 1949180Notes

Reaction equation

HRID 1949180 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]>[CH:1]1[CH:6]=[CH:5][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:3][CH:2]=1

Participants

7

Reactant 4

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

Product 1

HCID 667544(R)-PinocembrinYield 90%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 6228DimethylformamideSolvent

Procedure

4.8 g of the benzyl protected pinocembrin in R-configuration obtained in Example 4 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 stop 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 (R)-pinocembrin (3.1 g, yield 90%) with specific rotation [α]D20=+45.83° (c=0.515, methanol), and e.e %>99.3%.

Workup

  1. customobtained in Example 4
  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-5b3c85b5f965423995c2649508705985
Source dataset
uspto-grants-2013_03
Patent number
US08399691B2

Reaction notes

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