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

HRID 2269914Notes

Reaction equation

HRID 2269914 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 −51° C. (dry ice-methanol) was added, dropwise, 1M 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 collected 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. customthe organic layer was collected
  8. washThe layer was washed with brine
  9. dry with materialdried (MgSO4)
  10. customcollected

Sources & evidence

ORD record
ord-4ba67ced91d34990a899a23958eb1b01
Source dataset
uspto-grants-2001_12
Patent number
USRE037478E1

Reaction notes

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