Boron tribromide → 1-(4-(3-Chloropropoxy)-3-hydroxyphenyl]ethanone

HRID 1637990Notes

Reaction equation

HRID 1637990 reaction equation
[Cl:1][CH2:2][CH2:3][CH2:4][O:5][C:6]1[CH:11]=[CH:10][C:9]([C:12](=[O:14])[CH3:13])=[CH:8][C:7]=1[O:15]C.C(=O)=O.CO.B(Br)(Br)Br.C([O-])(O)=O.[Na+]>C(Cl)Cl>[Cl:1][CH2:2][CH2:3][CH2:4][O:5][C:6]1[CH:11]=[CH:10][C:9]([C:12](=[O:14])[CH3:13])=[CH:8][C:7]=1[OH:15]

Participants

6

Reactant 4

HCID 25134Boron tribromide2×HCID 516892Sodium Bicarbonate2×HCID 73142644-(3-Chloropropoxy)-3-methoxyacetophenoneHCID 21973728Carbon dioxide methanol

Product 1

HCID 103765071-(4-(3-Chloropropoxy)-3-hydroxyphenyl]ethanoneYield 86.4%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a stirred solution of 1-[4-(3-chloropropoxy)-3-methoxyphenyl]ethanone (10.0 g, 41 mmol) in methylene chloride (120 ml) cooled to -50° C. (dry ice-methanol) was added, dropwise, 1 M boron tribromide in methylene chloride (123 ml, 120 mmol). The temperature was kept between -40° C. and -50° C. After complete addition, the reaction was permitted to reach -30° C., and the TLC checked (ca. 15 min. after final boron tribromide was added). Saturated NaHCO3 was added, dropwise, never allowing the temperature to go above 0° C. during most of the addition. When sufficient NaHCO3 had been added to make the solution basic, the organic layer was; collected. The layer was washed with brine, dried (MgSO4), and concentrated to yield 8.1 g of dark brown oil, which solidified on standing. This was chromatographed on a Waters Prep 500 LC (2 silica columns, 2% methanol-methylene chloride as eluent). Upon concentration of the appropriate fractions, 5.8 g of a brown tacky solid were obtained. This was recrystallized from isopropyl ether (with decanting of the yellow isopropyl ether supernatant from the dark brown oily residue) to give initially 2.5 g; of a yellow solid. Concentration of the mother liquor gave an additional 0.5 g, m.p.=110-113° C.

Workup

  1. additionwas added
  2. customwas kept between -40° C. and -50° C
  3. additionAfter complete addition
  4. customto reach -30° C.
  5. customto go above 0° C.
  6. additionmost of the addition
  7. customcollected
  8. washThe layer was washed with brine
  9. dry with materialdried (MgSO4)
  10. concentrationconcentrated

Sources & evidence

ORD record
ord-db78fb16b008440bb06bee8f8ce3d5e1
Source dataset
uspto-grants-2000_03
Patent number
US06043240

Reaction notes

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