Water → 4-Bromo-6-chloro-2,3-dihydropyridazin-3-one

HRID 2069780Notes

Reaction equation

HRID 2069780 reaction equation
N([O-])=O.[Na+].[Br:5][C:6]1[CH:11]=[C:10]([Cl:12])[N:9]=[N:8][C:7]=1N.[OH2:14]>OS(O)(=O)=O.C(O)(=O)C>[Br:5][C:6]1[C:7](=[O:14])[NH:8][N:9]=[C:10]([Cl:12])[CH:11]=1

Participants

6

Reactant 3

HCID 962WaterHCID 220244193-Amino-4-bromo-6-chloropyridazineHCID 23668193Sodium Nitrite

Product 1

HCID 115865224-Bromo-6-chloro-2,3-dihydropyridazin-3-oneYield 95%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 1118Sulfuric AcidSolvent

Conditions

Temperature
20 °C

Procedure

To a cooled solution (0-5° C.) of NaNO2 (1 g, 13.20 mmol) in conc. H2SO4 (15 mL) was added 4-Bromo-6-chloro-pyridazin-3-ylamine (2.3 g, 11 mmol) in 50 mL of acetic acid. Then the reaction mixture was stirred for 1 h at 20° C. followed by addition of water (75 mL) and stirring continued for 5 h at RT. The reaction mixture extracted with EtOAc, dried over Na2SO4, concentrated under reduced pressure and crude purified by silica gel (100-200 mesh) chromatography using EtOAc/Hexane (8:2) to afford 4-Bromo-6-chloro-2H-pyridazin-3-one (2.2 g, 95%) yellowish solid.

Workup

  1. stirringstirring
  2. waitcontinued for 5 h at RT
  3. extractionThe reaction mixture extracted with EtOAc
  4. dry with materialdried over Na2SO4
  5. concentrationconcentrated under reduced pressure and crude
  6. custompurified by silica gel (100-200 mesh) chromatography

Sources & evidence

ORD record
ord-c66f97af0fe94136baa0542c63340480
Source dataset
uspto-grants-2012_10
Patent number
US08299077B2

Reaction notes

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