Potassium Carbonate → 4-Chloro-5-methoxy-2-methyl-2,3-dihydropyridazin-3-one

HRID 1842356Notes

Reaction equation

HRID 1842356 reaction equation
[Cl:1][C:2]1[C:3](=[O:10])[N:4]([CH3:9])[N:5]=[CH:6][C:7]=1Cl.[C:11]([O-])([O-])=[O:12].[K+].[K+]>CO>[Cl:1][C:2]1[C:3](=[O:10])[N:4]([CH3:9])[N:5]=[CH:6][C:7]=1[O:12][CH3:11]

Participants

4

Reactant 2

HCID 11430Potassium CarbonateHCID 1204623(2H)-Pyridazinone, 4,5-dichloro-2-methyl-

Product 1

HCID 27749384-Chloro-5-methoxy-2-methyl-2,3-dihydropyridazin-3-oneYield 93.8%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

10 g (55.8 mmoles) of intermediate 3a are placed in the presence of 115 g (837 mmoles) K2CO3 in 725 mL MeOH. The reaction medium is agitated for 1 h under reflux then filtered through celite. The filtrate is concentrated to dryness and the residue solubilized in CH2Cl2 and washed with water. After drying over Na2SO4, the organic phases are evaporated and the residue obtained is purified by silica gel flash chromatography (CH2Cl2—AcOEt, gradient 100:0 to 60:40 over 45 min). 9.14 g of intermediate 4b are thus obtained in the form of a white solid (yield 94%). TLC silica gel 60 F 254 Merck, CH2Cl2—AcOEt: 50:50, Rf=0.36.

Workup

  1. temperatureunder reflux
  2. filtrationthen filtered through celite
  3. concentrationThe filtrate is concentrated to dryness
  4. washthe residue solubilized in CH2Cl2 and washed with water
  5. dry with materialAfter drying over Na2SO4
  6. customthe organic phases are evaporated
  7. customthe residue obtained
  8. customis purified by silica gel flash chromatography (CH2Cl2—AcOEt, gradient 100:0 to 60:40 over 45 min)

Sources & evidence

ORD record
ord-c829844faa5c4166af00870fe51f45c5
Source dataset
uspto-grants-2015_02
Patent number
US08946225B2

Reaction notes

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