Hydrazinecarboxylic acid, ethyl ester → 6-(p-Bromophenyl)-1,2,4-triazolo[4,3-b]pyridazin-3(2H)-one

HRID 462408

Reaction equation

HRID 462408 reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[N:13]=[N:12][C:11](Cl)=[CH:10][CH:9]=2)=[CH:4][CH:3]=1.[C:15](OCC)(=[O:18])[NH:16][NH2:17]>C(O)CCC>[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[CH:9]=[CH:10][C:11]3[N:12]([C:15](=[O:18])[NH:16][N:17]=3)[N:13]=2)=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 20064Hydrazinecarboxylic acid, ethyl esterHCID 64052553-(4-Bromophenyl)-6-chloropyridazine

Product 1

HCID 134245986-(p-Bromophenyl)-1,2,4-triazolo[4,3-b]pyridazin-3(2H)-one

Reagents, catalysts & solvents 1

HCID 2631-ButanolSolvent

Procedure

A mixture of 2.69 g. of 6-(p-bromophenyl)-3-chloropyridazine (U.S. Pat. No. 4,092,311), 3.12 g. of ethyl carbazate and 50 ml. of n-butanol is heated at reflux for 16 hours, then cooled and filtered giving an orange solid which is saved. The filtrate is heated at reflux for 23 hours, then chilled in an ice bath and filtered giving more orange solid. The two crops are combined and recrystallized from dimethylformamide, giving 0.65 g. of the desired product as orange crystals, m.p. 348°-350° C. (dec.).

Workup

  1. additionA mixture of 2.69 g
  2. temperatureat reflux for 16 hours
  3. temperaturecooled
  4. filtrationfiltered
  5. customgiving an orange solid which
  6. temperatureThe filtrate is heated
  7. temperatureat reflux for 23 hours
  8. temperaturechilled in an ice bath
  9. filtrationfiltered
  10. customgiving more orange solid
  11. customrecrystallized from dimethylformamide
  12. customgiving 0.65 g

Sources & evidence

ORD record
ord-898f497980c34719baaee1bbc5ee6289
Source dataset
uspto-grants-1985_05
Patent number
US04515791

Linked notes

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