Acetone → 7-hydroxy-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-one

HRID 1849519Notes

Reaction equation

HRID 1849519 reaction equation
[CH3:1][C:2]([C:4]1[CH:5]=[CH:6][C:7]([OH:11])=[CH:8][C:9]=1[OH:10])=[O:3].N1C[CH2:15][CH2:14][CH2:13]1.CC(C)=O>C1(C)C=CC=CC=1>[OH:11][C:7]1[CH:8]=[C:9]2[C:4]([C:2](=[O:3])[CH2:1][C:14]([CH3:15])([CH3:13])[O:10]2)=[CH:5][CH:6]=1

Participants

5

Reactant 3

HCID 180AcetoneHCID 69902',4'-DihydroxyacetophenoneHCID 31268Pyrrolidine

Product 1

HCID 6009027-hydroxy-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-oneYield 33.8%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

To a solution of 2,4-dihydroxy acetophenone (6.00 g, 39.4 mmol) and pyrrolidine (15.0 mL, 181 mmol) in toluene (200 mL), acetone (22.9 g, 394 mmol) was added. After heated to reflux for 16 hrs, the solvents were removed and the residue was added HCl (2.0 N, 100 mL) and brine (200 mL) then the mixture was extracted with EtOAc (150×5 mL). The combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated. The crude product was purified by SGC (eluting with petroleum ether/ethyl acetate=6/1) to give target compound (2.56 g, 33%) as a brown yellow solid. LCMS (ESI) m/z: 191.1 [M−H]+; 1H-NMR (500 MHz, CDCl3): δ 7.79 (d, J=8.0 Hz, 1H), 6.49 (dd, J=8.5, 2.0 Hz, 1H), 6.36 (d, J=2.0 Hz, 1H), 2.68 (s, 2H), 1.45 (s, 6H).

Workup

  1. temperatureAfter heated
  2. temperatureto reflux for 16 hrs
  3. customthe solvents were removed
  4. additionthe residue was added HCl (2.0 N, 100 mL) and brine (200 mL)
  5. extractionthe mixture was extracted with EtOAc (150×5 mL)
  6. washThe combined organic layers were washed with brine
  7. dry with materialdried over Na2SO4
  8. filtrationfiltered
  9. concentrationconcentrated
  10. customThe crude product was purified by SGC (eluting with petroleum ether/ethyl acetate=6/1)

Sources & evidence

ORD record
ord-97eddb1deb764af89952e647f6009a3f
Source dataset
uspto-grants-2015_02
Patent number
US08952169B2

Reaction notes

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