Boron tribromide → 6-(4-Hydroxyphenyl)-2-methyl-3(2H)-pyridazinone

HRID 2042532Notes

Reaction equation

HRID 2042532 reaction equation
C[O:2][C:3]1[CH:8]=[CH:7][C:6]([C:9]2[CH:10]=[CH:11][C:12](=[O:16])[N:13]([CH3:15])[N:14]=2)=[CH:5][CH:4]=1.B(Br)(Br)Br>C(Cl)Cl>[OH:2][C:3]1[CH:8]=[CH:7][C:6]([C:9]2[CH:10]=[CH:11][C:12](=[O:16])[N:13]([CH3:15])[N:14]=2)=[CH:5][CH:4]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 7660034HCID 7660034, compound

Product 1

HCID 1359822716-(4-Hydroxyphenyl)-2-methyl-3(2H)-pyridazinone

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To 6-(4-methoxyphenyl)-2-methyl-2H-pyridazin-3-one (10 g, 46.3 mmol) in 15 mL DCM cooled on an ice-water bath to ˜5° C. was added 93 mL of BBr3 (1M soln in DCM) over 5 min. The ice bath was removed and the solution stirred at rt for 4 h. The reaction was cooled on an ice-bath and saturated NH4Cl solution (100 mL) added slowly. After the addition was complete, the DCM was removed under reduced pressure, excess water added and the product collected, washed 1× with MeOH (˜20 mL) and dried to give 9.2 g (98%): Mp 242-245° C. 1H NMR (DMSO-d6) δ 3.8 (s, 3H), 6.85 (d, 2H), 7.0 (d, 1H), 7.7 (d, 2H), 7.95 (d, 1H), 9.8 (s, 1H); MS m/z=203 (M+H).

Workup

  1. customThe ice bath was removed
  2. temperatureThe reaction was cooled on an ice-bath
  3. additionsaturated NH4Cl solution (100 mL) added slowly
  4. additionAfter the addition
  5. customthe DCM was removed under reduced pressure, excess water
  6. additionadded
  7. customthe product collected
  8. washwashed 1× with MeOH (˜20 mL)
  9. customdried
  10. customto give 9.2 g (98%)

Sources & evidence

ORD record
ord-fd5fc8a851454902bdf983c0905f18ee
Source dataset
uspto-grants-2013_11
Patent number
US08586588B2

Reaction notes

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