Sulfuric Acid → 2,3-Dichloro-5-methyl-1H-pyrrolo[2,3-d]pyridazin-4(5H)-one

HRID 1291209Notes

Reaction equation

HRID 1291209 reaction equation
[CH3:1][NH:2][NH2:3].[C:4]([C:9]1[C:13]([Cl:14])=[C:12]([Cl:15])[NH:11][C:10]=1[CH:16]=O)(OCC)=[O:5].S(=O)(=O)(O)O>C(O)C>[Cl:15][C:12]1[NH:11][C:10]2[CH:16]=[N:3][N:2]([CH3:1])[C:4](=[O:5])[C:9]=2[C:13]=1[Cl:14]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 6061MethylhydrazineHCID 148408443-Carbethoxy-4,5-dichloro-2-formylpyrrole

Product 1

HCID 1356675802,3-Dichloro-5-methyl-1H-pyrrolo[2,3-d]pyridazin-4(5H)-oneYield 81%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A solution of methylhydrazine (4.72 g) and 3-carbethoxy-4,5-dichloro-2-formylpyrrole (4.72 g) in ethanol (50 ml) was refluxed for 2 hours. After cooling to room temperature, concentrated sulfuric acid (0.5 ml) was added and the mixture was refluxed for another 21 hours. The reaction mixture was cooled to room temperature and the resulting crystals were collected by filtration. The crystals were rinsed with ethanol and ether and dried in vacuo to provide the title compound as brown powder (3.29 g; yield 81%). H-NMR (DMSO-d6) δ: 3.66(3H,s), 8.11(1H,s).

Workup

  1. temperaturethe mixture was refluxed for another 21 hours
  2. temperatureThe reaction mixture was cooled to room temperature
  3. filtrationthe resulting crystals were collected by filtration
  4. washThe crystals were rinsed with ethanol and ether
  5. customdried in vacuo

Sources & evidence

ORD record
ord-9896931c0ddc4db5be803d3e9cca8f8d
Source dataset
uspto-grants-1998_05
Patent number
US05753664

Reaction notes

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