Ethyl 2-chloroacetoacetate → Ethyl 6-chloro-2-methylimidazo[1,2-b]pyridazine-3-carboxylate

HRID 1067598Notes

Reaction equation

HRID 1067598 reaction equation
[NH2:1][C:2]1[N:3]=[N:4][C:5]([Cl:8])=[CH:6][CH:7]=1.Cl[CH:10]([C:16](=O)[CH3:17])[C:11]([O:13][CH2:14][CH3:15])=[O:12]>C(O)C>[Cl:8][C:5]1[CH:6]=[CH:7][C:2]2[N:3]([C:10]([C:11]([O:13][CH2:14][CH3:15])=[O:12])=[C:16]([CH3:17])[N:1]=2)[N:4]=1

Participants

4

Reactant 2

HCID 11858Ethyl 2-chloroacetoacetateHCID 216436-Amino-3-chloropyridazine

Product 1

HCID 14091884Ethyl 6-chloro-2-methylimidazo[1,2-b]pyridazine-3-carboxylateYield 12.9%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

12.9 g of 3-amino-6-chloropyridazine was suspended in 250 ml of ethanol; 18.1 g of ethyl 2-chloro-3-oxobutanoate was added, followed by thermal refluxing for 6 hours. After cooling, the mixture was concentrated under reduced pressure; the residue was ajusted to pH 7 by the addition of aqueous sodium bicarbonate; ethyl ether was added; the precipitated was collected by filtration and extracted with ethyl ether; the extract was washed with saturated saline and dried with magnesium sulfate. The dry product was concentrated under reduced pressure; ethanol-1 N aqueous solution of sodium hydroxide (1:1) was added; the crystal precipitated was collected by filtration; the filtrate was concentrated again. The residue was crystallized by the addition of ethyl acetate and collected by filtration to yield 3.09 g of the title compound.

Workup

  1. customrefluxing for 6 hours
  2. temperatureAfter cooling
  3. concentrationthe mixture was concentrated under reduced pressure
  4. additionthe residue was ajusted to pH 7 by the addition of aqueous sodium bicarbonate
  5. additionethyl ether was added
  6. filtrationthe precipitated was collected by filtration
  7. extractionextracted with ethyl ether
  8. washthe extract was washed with saturated saline
  9. dry with materialdried with magnesium sulfate
  10. concentrationThe dry product was concentrated under reduced pressure
  11. additionethanol-1 N aqueous solution of sodium hydroxide (1:1) was added
  12. customthe crystal precipitated
  13. filtrationwas collected by filtration
  14. concentrationthe filtrate was concentrated again
  15. customThe residue was crystallized by the addition of ethyl acetate
  16. filtrationcollected by filtration

Sources & evidence

ORD record
ord-00889c66e5854662b5802d157ae14b44
Source dataset
uspto-grants-2001_06
Patent number
US06248740B1

Reaction notes

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