4-Chloro-5-hydroxy-2-(phenylmethyl)-3(2H)-pyridazinone → 2-benzyl-5-hydroxy-3(2H)-pyridazinone

HRID 1197779Notes

Reaction equation

HRID 1197779 reaction equation
[CH2:1]([N:8]1[C:13](=[O:14])[C:12](Cl)=[C:11]([OH:16])[CH:10]=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1>[OH-].[Na+].[Pd]>[CH2:1]([N:8]1[C:13](=[O:14])[CH:12]=[C:11]([OH:16])[CH:10]=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

4

Reactant 1

HCID 546831804-Chloro-5-hydroxy-2-(phenylmethyl)-3(2H)-pyridazinone

Product 1

HCID 547367352-benzyl-5-hydroxy-3(2H)-pyridazinoneYield 96%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 14798Sodium HydroxideSolvent

Procedure

To the mixture of 60 g of 2-benzyl-4,5-dichloro-3(2H)-pyridazinone and 38.8 g of potassium hydroxide was added 250 ml of ethanol and 150 ml of water and heated in an oil bath to the refluxing temperature for 10 hours. After reaction the solvent was distilled off under reduced pressure, and to the residual solution was added 200 ml of water and washed twice with chloroform, the water layer was acidified with concentrated hydrochloric acid. The white solid thus separated was filtered off, washed with water and dried to obtain 55 g of 2-benzyl-4-chloro-5-hydroxy-3(2H)-pyridazinone. Subsequently, in aqueous sodium hydroxide solution (NaOH 1.82 g, water 20 ml) were added 5.0 g of 2-benzyl-4-chloro-5-hydroxy-3(2H)-pyridazinone and 200 mg of 5 % Pd/C , then 474 ml of hydrogen gas was absorbed in the solution under normal pressure. After reaction, Pd/C was filtered off and to the solution was added concentrated hydrochloric acid to be acidified. The white solid thus separated was filtered off, washed with water and dried to obtain 4.1 g of 2-benzyl-5-hydroxy-3(2H)-pyridazinone.

Workup

  1. custom474 ml of hydrogen gas was absorbed in the solution under normal pressure
  2. customAfter reaction, Pd/C
  3. filtrationwas filtered off and to the solution
  4. additionwas added concentrated hydrochloric acid
  5. customThe white solid thus separated
  6. filtrationwas filtered off
  7. washwashed with water
  8. customdried

Sources & evidence

ORD record
ord-008bbbc4a5dd4cf08355d50c92b6e0b9
Source dataset
uspto-grants-1994_01
Patent number
US05278163

Reaction notes

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