Sodium → 6-chloro-2H,3H-[1,2,4]triazolo[4,3-b]pyridazin-3-one

HRID 1730876Notes

Reaction equation

HRID 1730876 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]([NH:8][NH2:9])[N:4]([C:10]([O:12]CC)=O)[N:3]=1.[Na]>C(O)C>[Cl:1][C:2]1[CH:7]=[CH:6][C:5]2[N:4]([C:10](=[O:12])[NH:9][N:8]=2)[N:3]=1

Participants

4

Reactant 2

HCID 5360545SodiumHCID 71390186Ethyl 3-chloro-6-hydrazinylpyridazine-1(6H)-carboxylate

Product 1

HCID 64071826-chloro-2H,3H-[1,2,4]triazolo[4,3-b]pyridazin-3-one

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

39 g. of 3-chloro-6-hydrazino-1(6H)pyridazinecarboxylic acid, ethyl ester (0.18 mol.) are added to a solution of 4.9 g. of sodium (0.216 mol.) in 400 ml. of absolute ethanol and the mixture is then refluxed for 4 hours with stirring. After cooling, the sodium salt of 6-chloro-1,2,4,-triazolo[4,3-b]pyridazin-3(2H)-one is filtered off, washed with ether and, after drying, dissolved in water. Acidification with acetic acid (25%) precipitates the free compound which then is filtered off, washed with water and dried, yielding 26 g. (85%) of 6-chloro-1,2,4-triazolo[4,3-b]pyridazin-3(2H)one, which is recrystallized from ethanol, m.p. 273°-274° .

Workup

  1. temperatureAfter cooling
  2. filtrationthe sodium salt of 6-chloro-1,2,4,-triazolo[4,3-b]pyridazin-3(2H)-one is filtered off
  3. washwashed with ether
  4. customafter drying
  5. dissolutiondissolved in water
  6. customAcidification with acetic acid (25%) precipitates the free compound which
  7. filtrationthen is filtered off
  8. washwashed with water
  9. customdried
  10. customyielding 26 g
  11. custom(85%) of 6-chloro-1,2,4-triazolo[4,3-b]pyridazin-3(2H)one, which is recrystallized from ethanol, m.p. 273°-274°

Sources & evidence

ORD record
ord-470a46d588b1474fae5c020783146b1b
Source dataset
uspto-grants-1976_11
Patent number
US03994898

Reaction notes

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