Methyl iodide → 3(2H)-Pyridazinone, 4,5-dichloro-2-methyl-

HRID 1842355Notes

Reaction equation

HRID 1842355 reaction equation
[Cl:1][C:2]1[C:3](=[O:9])[NH:4][N:5]=[CH:6][C:7]=1[Cl:8].[C:10]([O-])([O-])=O.[K+].[K+].IC>[Br-].C([N+](CCCC)(CCCC)CCCC)CCC.C(#N)C>[Cl:1][C:2]1[C:3](=[O:9])[N:4]([CH3:10])[N:5]=[CH:6][C:7]=1[Cl:8]

Participants

6

Reactant 3

HCID 6328Methyl iodideHCID 11430Potassium CarbonateHCID 732474,5-Dichloro-3-hydroxypyridazine

Product 1

HCID 1204623(2H)-Pyridazinone, 4,5-dichloro-2-methyl-Yield 70.7%

Reagents, catalysts & solvents 2

HCID 74236Tetrabutylammonium BromideCatalystHCID 6342AcetonitrileSolvent

Conditions

Temperature
115 °C

Procedure

25 g (151 mmoles) of 4,5-dichloropyridazinone are placed in a stainless steel reactor in the presence of 25.13 g (181 mmoles) K2CO3, 1 g (3.03 mmoles) of tetrabutylammonium bromide and 14.2 mL (227 mmoles) of iodomethane in 150 mL acetonitrile. The reaction medium is agitated for 4 h at 115° C. then filtered. The filtrate is concentrated to dryness then solubilized in AcOEt and washed in acid water (pH 1), then with NaCl-saturated water. After drying over Na2SO4, the organic phases are evaporated and the residue obtained is purified by silica gel flash chromatography (CH2Cl2). 19.1 g of intermediate 3a are thus obtained in the form of a yellow solid (yield 70%). TLC silica gel 60 F 254 Merck, petroleum ether-AcOEt: 70:30, Rf=0.48.

Workup

  1. filtrationthen filtered
  2. concentrationThe filtrate is concentrated to dryness
  3. washwashed in acid water (pH 1)
  4. dry with materialAfter drying over Na2SO4
  5. customthe organic phases are evaporated
  6. customthe residue obtained
  7. customis purified by silica gel flash chromatography (CH2Cl2)

Sources & evidence

ORD record
ord-b242191848084af19284d290a2def870
Source dataset
uspto-grants-2015_02
Patent number
US08946225B2

Reaction notes

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