Hydrochloric Acid → 2,10-dihydro-1H-fluoreno[2,1-b]furan-10-one

HRID 617417Notes

Reaction equation

HRID 617417 reaction equation
[C:1]1([C:7]2[C:15]([C:16]([OH:18])=O)=[C:11]3[CH2:12][CH2:13][O:14][C:10]3=[CH:9][CH:8]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[Cl-].[Al+3].[Cl-].[Cl-].Cl.C(Cl)Cl>S(Cl)(Cl)=O>[CH2:12]1[CH2:13][O:14][C:10]2[CH:9]=[CH:8][C:7]3[C:1]4[C:2]([C:16](=[O:18])[C:15]=3[C:11]1=2)=[CH:3][CH:4]=[CH:5][CH:6]=4

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 6344DichloromethaneHCID 6451240Aluminum(III) ChlorideHCID 218521852,3-Dihydro-5-phenyl-4-benzofurancarboxylic acid

Product 1

HCID 218521842,10-dihydro-1H-fluoreno[2,1-b]furan-10-oneYield 77.7%

Reagents, catalysts & solvents 1

HCID 24386Thionyl ChlorideSolvent

Procedure

A magnetically stirred solution of 2,3-dihydro-5-phenyl-4-benzofurancarboxylic acid (0.730 g, 3.04 mmol) in thionyl chloride (250 mL) was heated at reflux for 3 h. The solvent was removed by concentration in vacuo. The residue was digested with CH2Cl2 (150 mL) and the solution concentrated in vacuo. This process was repeated twice. The residue was digested with CH2Cl2 (260 mL) and treated with anhydrous aluminum chloride (0.40 g, 3.00 mmol). The resultant suspension was stirred for 2 h, poured over ice (250 g), treated with 1 N HCl (250 mL) and CH2Cl2 (250 mL), the layers were separated, and the aqueous layer further extracted with fresh CH2Cl2 (3×200 mL). The combined organic extracts were washed with brine (500 mL), dried (K2CO3), filtered, and concentrated in vacuo to give 0.525 g of 2,10-dihydro-1H-fluoreno[2,1-b]furan-10-one: 1H NMR (300 MHz, CDCl3) δ 3.44 (t, J=8.5 Hz, 2H), 4.65 (t, J=8.5 Hz, 2H), 6.78 (d, J=8 Hz, 1H), 7.18 (dt, J=1.5, 8 Hz, 1H), 7.25 (d, J=8 Hz, 1H), 7.39 (d, J=8 Hz, 1H), 7.41 (dt, J=2, 8 Hz, 1H), 7.57(d, J=8 Hz, 1H).

Workup

  1. temperatureat reflux for 3 h
  2. customThe solvent was removed by concentration in vacuo
  3. concentrationthe solution concentrated in vacuo
  4. customthe layers were separated
  5. extractionthe aqueous layer further extracted with fresh CH2Cl2 (3×200 mL)
  6. washThe combined organic extracts were washed with brine (500 mL)
  7. dry with materialdried (K2CO3)
  8. filtrationfiltered
  9. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-aedb8c2e3fef435cb995b4f70f3e8d88
Source dataset
uspto-grants-1999_09
Patent number
US05948817

Reaction notes

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