Acetic Acid → HCID 54428392, compound

HRID 2231892Notes

Reaction equation

HRID 2231892 reaction equation
[CH2:1]([O:3][C:4](=[O:20])[CH2:5][CH2:6][C:7]1([CH3:19])[CH2:12][C:11](=O)[C:10]2[CH:14]=[CH:15][C:16]([OH:18])=[CH:17][C:9]=2[O:8]1)[CH3:2].B(F)(F)F.CCOCC.B.C(O)(=O)C>O1CCCC1>[CH2:1]([O:3][C:4](=[O:20])[CH2:5][CH2:6][C:7]1([CH3:19])[CH2:12][CH2:11][C:10]2[CH:14]=[CH:15][C:16]([OH:18])=[CH:17][C:9]=2[O:8]1)[CH3:2]

Participants

6

Reactant 4

HCID 176Acetic AcidHCID 6331BoraneHCID 8000Boron trifluoride etherateHCID 14842375HCID 14842375, compound

Product 1

HCID 54428392HCID 54428392, compoundYield 63.2%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To a stirred solution of 1.5 g of racemic-3,4-dihydro-7-hydroxy-2-methyl-4-oxo-2H-1-benzopyran-2-propanoic acid ethyl ester in 8 ml of dry tetrahydrofuran, with ice bath cooling, was added 1.4 ml of boron trifluoride etherate, over a period of 2 minutes. The mixture was stirred at 0°-5° C. for 5 minutes whereupon 5.4 ml of 1M borane in tetrahydrofuran was added. Stirring was continued at 0°-5° C. for 2.5 hours then the mixture was decomposed by the addition of glacial acetic acid. Solvents were removed in vacuo then the residue was dissolved in methylene chloride. The solution was washed with sodium bicarbonate solution and brine, then dried, filtered and concentrated under reduced pressure. The residual orange oil (1.4 g) was chromatographed on 50 g of silica gel. Elution with 4:1 hexane-ethyl acetate afforded 0.9 g (63.1%) of racemic-3,4-dihydro-7-hydroxy-2-methyl-2H-1-benzopyran-2-propanoic acid ethyl ester as a colorless oil.

Workup

  1. additionwas added
  2. waitwas continued at 0°-5° C. for 2.5 hours
  3. customSolvents were removed in vacuo
  4. dissolutionthe residue was dissolved in methylene chloride
  5. washThe solution was washed with sodium bicarbonate solution and brine
  6. customdried
  7. filtrationfiltered
  8. concentrationconcentrated under reduced pressure
  9. customThe residual orange oil (1.4 g) was chromatographed on 50 g of silica gel
  10. washElution with 4:1 hexane-ethyl acetate

Sources & evidence

ORD record
ord-845d46e4de9c4587b95cc4ca9d7cc8b4
Source dataset
uspto-grants-1988_11
Patent number
US04785017

Reaction notes

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