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

HRID 1169141Notes

Reaction equation

HRID 1169141 reaction equation
[NH2:1][C:2]1[N:3]=[N:4][C:5]([Cl:8])=[CH:6][CH:7]=1.Br[CH:10]([CH3:17])[C:11](=O)[C:12]([O:14][CH3:15])=[O:13].[CH2:18](N(C(C)C)C(C)C)C>C(O)C>[Cl:8][C:5]1[CH:6]=[CH:7][C:2]2[N:3]([C:10]([CH3:17])=[C:11]([C:12]([O:14][CH2:15][CH3:18])=[O:13])[N:1]=2)[N:4]=1

Participants

5

Reactant 3

HCID 216436-Amino-3-chloropyridazineHCID 81531DiisopropylethylamineHCID 11183175Methyl 3-bromo-2-oxobutanoate

Product 1

HCID 22989254Ethyl 6-chloro-3-methylimidazo[1,2-b]pyridazine-2-carboxylate

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

5.83 g of 3-amino-6-chloropyridazine was suspended in 70 ml of ethanol; 9.75 g of methyl 3-bromo-2-oxobutyrate and 8.6 ml of N-ethyldiisopropylamine were added, followed by thermal refluxing for 5 hours. After cooling, the mixture was concentrated under reduced pressure. The residue was adjusted to pH 7 by the addition of an aqueous solution of sodium hydrogen carbonate and extracted with ethyl acetate-tetrahydrofuran(1:1); the extract was washed with saline, dried over magnesium sulfate and concentrated under reduced pressure; ethyl acetate was added to the residue; the crystal precipitated was collected by filtration, washed with ethyl acetate and dried to yield 3.9 g of the title compound.

Workup

  1. customrefluxing for 5 hours
  2. temperatureAfter cooling
  3. concentrationthe mixture was concentrated under reduced pressure
  4. additionThe residue was adjusted to pH 7 by the addition of an aqueous solution of sodium hydrogen carbonate
  5. extractionextracted with ethyl acetate-tetrahydrofuran(1:1)
  6. washthe extract was washed with saline
  7. dry with materialdried over magnesium sulfate
  8. concentrationconcentrated under reduced pressure
  9. additionethyl acetate was added to the residue
  10. customthe crystal precipitated
  11. filtrationwas collected by filtration
  12. washwashed with ethyl acetate
  13. customdried

Sources & evidence

ORD record
ord-46f9683357e54fe18f932be32947bf47
Source dataset
uspto-grants-2003_09
Patent number
US06627630B1

Reaction notes

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