6-Amino-3-chloropyridazine → Ethyl 7-chloro-4-oxo-4H-pyrimido[1,2-b]pyridazine-3-carboxylate

HRID 224227Notes

Reaction equation

HRID 224227 reaction equation
[Cl:1][C:2]1[N:3]=[N:4][C:5]([NH2:8])=[CH:6][CH:7]=1.C([O:11][CH:12]=[C:13]([C:19]([O-])=O)[C:14]([O:16][CH2:17][CH3:18])=[O:15])C>C1(OC2C=CC=CC=2)C=CC=CC=1.CCCCCC>[CH2:17]([O:16][C:14]([C:13]1[C:12](=[O:11])[N:4]2[N:3]=[C:2]([Cl:1])[CH:7]=[CH:6][C:5]2=[N:8][CH:19]=1)=[O:15])[CH3:18]

Participants

5

Reactant 2

HCID 216436-Amino-3-chloropyridazineHCID 858292113-Ethoxy-2-ethoxycarbonylprop-2-enoate

Product 1

HCID 13437596Ethyl 7-chloro-4-oxo-4H-pyrimido[1,2-b]pyridazine-3-carboxylate

Reagents, catalysts & solvents 2

HCID 7583Diphenyl EtherSolventHCID 8058HexaneSolvent

Procedure

A mixture of 3-chloro-6-aminopyridazine [J. Druey et al., Helv. Chim. Acta., 37, 121 (1954)] (8.20 g, 63.56 m mol) and ethyl ethoxymethylenemalonate (15.0 g, 69.4 m mol) in diphenyl ether (70 ml) was heated to distil out ethanol produced. After cooling, the mixture was diluted with n-hexane (300 ml) to precipitate the crude title product, which was dissolved in chloroform (200 ml), treated with a small amount of carbon and evaporated under reduced pressure to 50 ml. The residual solution was diluted with n-hexane (200 ml) to precipitate pure title product. Yield, 7.73 g (56%), M.p. 149°-152° C.

Workup

  1. temperaturewas heated
  2. customto distil out ethanol
  3. customproduced
  4. temperatureAfter cooling
  5. customto precipitate the crude title product, which
  6. dissolutionwas dissolved in chloroform (200 ml)
  7. additiontreated with a small amount of carbon
  8. customevaporated under reduced pressure to 50 ml
  9. additionThe residual solution was diluted with n-hexane (200 ml)
  10. customto precipitate pure title product
  11. customYield

Sources & evidence

ORD record
ord-0e1c96b5cbad4132a04e817a666ebd83
Source dataset
uspto-grants-1980_11
Patent number
US04231928

Reaction notes

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