Bromine → 3-Phenyl-naphtho[2,3-b]furan-4,9-dione

HRID 540649

Reaction equation

HRID 540649 reaction equation
[N+](/[CH:4]=[CH:5]/[C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1)([O-])=O.BrBr.N12CCCN=C1CCCCC2.[OH:25][C:26]1[C:27](=[O:37])[C:28]2[C:33]([C:34](=[O:36])[CH:35]=1)=[CH:32][CH:31]=[CH:30][CH:29]=2>ClCCl>[C:6]1([C:5]2[C:35]3[C:34](=[O:36])[C:33]4[C:28](=[CH:29][CH:30]=[CH:31][CH:32]=4)[C:27](=[O:37])[C:26]=3[O:25][CH:4]=2)[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1

Participants

6

Reactant 4

HCID 24408BromineHCID 811841,8-Diazabicyclo(5.4.0)undec-7-ene2×HCID 5284459beta-nitrostyrene, (E)-HCID 178516607HCID 178516607, compound

Product 1

HCID 665845933-Phenyl-naphtho[2,3-b]furan-4,9-dioneYield 70%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To the solution of 5 grams (33.5 mmoles) of [(E)-2-nitroethenyl]benzene in 100 mL of dichloromethane, 5.6 grams (35.2 mmoles) of bromine was added. The mixture was refluxed for 12 hours, and then evaporated to dryness. To the residue solution in 150 mL of tetrahydrofuran cooled in ice bath, 5.3 grams (35.2 mmoles) of 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) was dropped slowly over 20 minutes while stirring vigorously. The reaction mixture was further stirred for 30 minutes in ice bath, then 5.8 grams (33.5 mmoles) of 2-hydroxy-1,4-naphthoquinone and 5.3 grams (35.2 mmoles) of 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) were added. The mixture was reflux for 3 hours, and then evaporated to sticky residue. The residue was dissolved in 300 mL of dichloromethane, and washed with 300 mL of water, 300 mL of 2% aqueous citric acid solution, successively, and dried with 30 grams of anhydrous sodium sulfate. The 3-phenyl-naphtho[2,3-b]furan-4,9-dione product was purified with silica gel column using dichloromethane/hexane (3:1) as elution solvent. 6.4 grams of product (overall yield 70%) was obtained and characterized by 1H NMR and mass spectrum. 1H NMR (in DMSO) δ 7.44-7.52 (m, 3H), 7.77-7.79 (m, 2H), 7.89-7.93 (m, 2H), 8.10-8.15 (m, 2H), 8.58 (s, 1H). Mass (M+H) is 275.

Workup

  1. temperatureThe mixture was refluxed for 12 hours
  2. customevaporated to dryness
  3. temperatureTo the residue solution in 150 mL of tetrahydrofuran cooled in ice bath
  4. stirringThe reaction mixture was further stirred for 30 minutes in ice bath
  5. temperatureThe mixture was reflux for 3 hours
  6. customevaporated to sticky residue
  7. dissolutionThe residue was dissolved in 300 mL of dichloromethane
  8. washwashed with 300 mL of water, 300 mL of 2% aqueous citric acid solution
  9. dry with materialsuccessively, and dried with 30 grams of anhydrous sodium sulfate
  10. customThe 3-phenyl-naphtho[2,3-b]furan-4,9-dione product was purified with silica gel column
  11. washas elution solvent

Sources & evidence

ORD record
ord-5fb35e951854441c91002000acbc6718
Source dataset
uspto-grants-2014_10
Patent number
US08871802B2

Linked notes

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