Potassium Hydroxide → 2-Benzyl-4-bromo-5-hydroxy-2h-pyridazin-3-one

HRID 612400Notes

Reaction equation

HRID 612400 reaction equation
[CH2:1]([N:8]1[C:13](=[O:14])[C:12]([Br:15])=[C:11](Br)[CH:10]=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[OH-:17].[K+]>CN(P(N(C)C)(N(C)C)=O)C>[CH2:1]([N:8]1[C:13](=[O:14])[C:12]([Br:15])=[C:11]([OH:17])[CH:10]=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 14797Potassium HydroxideHCID 99026992-benzyl-4,5-dibromopyridazin-3(2H)-one

Product 1

HCID 546811742-Benzyl-4-bromo-5-hydroxy-2h-pyridazin-3-oneYield 40%

Reagents, catalysts & solvents 1

HCID 12679HexamethylphosphoramideSolvent

Procedure

The residue from step 1 was dissolved in HMPA (50 mL) and 8N KOH (65 mL) was added. The mixture was warmed to 120°-125° C. and stirred vigourously for 16 h. The mixture was cooled to r.t., the aqueous layer was separated, diluted with H2O (500 mL) and acidified to pH 6 with 6N HCl under vigourous stirring. After cooling in an ice bath, the solid was collected and air dried. It was dissolved in warm IN NaOH and washed once with ETOAc. The aqueous layer was acidified to pH 6 with 6N HCl and cooled again in an ice bath. The solid was filtered and air dried to yield the title compound (4.4 g, 40 %).

Workup

  1. temperatureThe mixture was warmed to 120°-125° C.
  2. customthe aqueous layer was separated
  3. additiondiluted with H2O (500 mL)
  4. temperatureAfter cooling in an ice bath
  5. customthe solid was collected
  6. customair dried
  7. dissolutionIt was dissolved
  8. temperaturein warm IN NaOH
  9. washwashed once with ETOAc
  10. temperaturecooled again in an ice bath
  11. filtrationThe solid was filtered
  12. customair dried

Sources & evidence

ORD record
ord-4dce9ca10250406ca8bff3b197657da8
Source dataset
uspto-grants-1999_12
Patent number
US06004960

Reaction notes

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