Boron tribromide → 1-[2-(6-Hydroxy-2-naphthyl)-1-benzofuran-3-yl]-1-pentanone

HRID 1359192Notes

Reaction equation

HRID 1359192 reaction equation
C[O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[CH:9]=[C:8]([C:13]1[O:14][C:15]3[CH:27]=[CH:26][CH:25]=[CH:24][C:16]=3[C:17]=1[C:18](=[O:23])[CH2:19][CH2:20][CH2:21][CH3:22])[CH:7]=[CH:6]2.B(Br)(Br)Br>C(Cl)Cl>[OH:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[CH:9]=[C:8]([C:13]1[O:14][C:15]3[CH:27]=[CH:26][CH:25]=[CH:24][C:16]=3[C:17]=1[C:18](=[O:23])[CH2:19][CH2:20][CH2:21][CH3:22])[CH:7]=[CH:6]2

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 113372811-[2-(6-Methoxy-2-naphthyl)-1-benzofuran-3-yl]-1-pentanone

Product 1

HCID 113368791-[2-(6-Hydroxy-2-naphthyl)-1-benzofuran-3-yl]-1-pentanoneYield 74.8%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a cooled (−78° C.) solution of 1-[2-(6-methoxy-2-naphthyl)-1-benzofuran-3-yl]-1-pentanone (4.2 g, 12 mmol) in methylene chloride (45 mL), was added, dropwise, 1 N boron tribromide in methylene chloride (25 mL, 25 mmol). The reaction mixture was stirred at room temperature for 3 hours, 45 minutes. The mixture was cooled to −11° C. and quenched, dropwise, with methanol (25 mL), then poured into excess water, and diluted with additional methylene chloride. The organic phase was washed with brine, dried over anhydrous magnesium sulfate, filtered, and solvent evaporated. The residue was purified by flash chromatography (Biotage apparatus) using 5-20% ethyl acetate in hexane as an eluant to afford 1-[2-(6-hydroxy-2-naphthyl)-1-benzofuran-3-yl]-1-pentanone as a yellow solid (3.09 g), mp 148-149° C. Mass spectrum (+EI, M+) m/z 344; 1HNMR (400 MHz, DMSO-d6): δ10.1 (d, 1H, J=4.0 Hz), 8.3 (d, 1H, J=1.1 Hz), 8.0-8.05 (m, 1H), 7.95 (d, 1H, J=8.8 Hz), 7.85 (d, 1H, J=8.6 Hz), 7.7-7.75 (m, 2H), 7.35-7.45 (m, 2H), 7.15-7.25 (m, 2H), 2.75 (t, 2H, J=7.4 Hz), 1.5-1.55 (m, 2H), 1.1-1.15 (m, 2H), and 0.7 ppm (t, 3H, J=7.4 Hz). Elemental Analysis for C23H20O3: Calculated: C, 80.21; H, 5.85; N, 0.00. Found: C, 79.92; H, 5.81; N, 0.12.

Workup

  1. additionwas added
  2. temperatureThe mixture was cooled to −11° C.
  3. customquenched
  4. additiondropwise, with methanol (25 mL), then poured into excess water
  5. additiondiluted with additional methylene chloride
  6. washThe organic phase was washed with brine
  7. dry with materialdried over anhydrous magnesium sulfate
  8. filtrationfiltered
  9. customsolvent evaporated
  10. customThe residue was purified by flash chromatography (Biotage apparatus)

Sources & evidence

ORD record
ord-13542d570cbf49ef9630b754edd5aa2f
Source dataset
uspto-grants-2003_07
Patent number
US06599925B2

Reaction notes

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