Citraconic Anhydrides → 1,2-dihydro-1-benzyl-4-methyl-3,6-pyridazinedione

HRID 895970Notes

Reaction equation

HRID 895970 reaction equation
[C:1]1(=[O:8])O[C:5](=[O:6])[CH:4]=[C:2]1[CH3:3].Cl.Cl.[CH2:11]([NH:18][NH2:19])[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1.C([O-])(=O)C.[K+]>C(O)(=O)C>[CH2:11]([N:18]1[C:5](=[O:6])[CH:4]=[C:2]([CH3:3])[C:1](=[O:8])[NH:19]1)[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1

Participants

5

Reactant 3

HCID 12012Citraconic AnhydridesHCID 146540Benzylhydrazine dihydrochlorideHCID 517044Potassium Acetate

Product 1

HCID 5619391,2-dihydro-1-benzyl-4-methyl-3,6-pyridazinedione

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

A slurry of citraconic anhydride (5.61 g, 50.0 mmol), benzylhydrazine dihydrochloride (9.80 g, 50.0 mmol) and potassium acetate (9.80 g, 100 mmol) in acetic acid (100 mL) was heated to reflux for 17 h. The reaction mixture was cooled and filtered. The filtrate was evaporated under reduced pressure and re-evaporated from toluene. The gummy yellow residue was partitioned between sodium carbonate solution (90 mL, 4 N) and EtOAc (50 mL). The aqueous extract was washed once with EtOAc and then slowly added to hydrochloric acid (3 M, 140 mL). The resulting white precipitate was collected, washed with water and dissolved in chloroform (1 L). The insoluble material was collected and boiled in EtOAc and filtered hot, to give 1,2-dihydro-1-benzyl-4-methyl-3,6-pyridazinedione as a white solid, mp >200° C. (1.85 g, 17%). Part IA compound.

Workup

  1. temperatureto reflux for 17 h
  2. temperatureThe reaction mixture was cooled
  3. filtrationfiltered
  4. customThe filtrate was evaporated under reduced pressure
  5. customre-evaporated from toluene
  6. customThe gummy yellow residue was partitioned between sodium carbonate solution (90 mL, 4 N) and EtOAc (50 mL)
  7. extractionThe aqueous extract
  8. washwas washed once with EtOAc
  9. additionslowly added to hydrochloric acid (3 M, 140 mL)
  10. customThe resulting white precipitate was collected
  11. washwashed with water
  12. dissolutiondissolved in chloroform (1 L)
  13. customThe insoluble material was collected
  14. filtrationfiltered hot

Sources & evidence

ORD record
ord-4ec74c0dd53b4866bbd86624ad0e50fe
Source dataset
uspto-grants-2005_07
Patent number
US06919323B2

Reaction notes

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