Hydrazine → 4-Bromopyridazine-3,6-diol

HRID 2306585Notes

Reaction equation

HRID 2306585 reaction equation
O.[NH2:2][NH2:3].[Br:4][C:5]1[C:6](O[C:9](=[O:11])[CH:10]=1)=[O:7].NN>C1COCC1>[Br:4][C:5]1[C:6](=[O:7])[NH:2][NH:3][C:9](=[O:11])[CH:10]=1

Participants

5

Reactant 3

HCID 9321HydrazineHCID 24654Hydrazine hydrate (1:1)HCID 800273-Bromo-2,5-furandione

Product 1

HCID 2549424-Bromopyridazine-3,6-diolYield 77%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

Hydrazine hydrate (28 ml, 576 mmol) was added dropwise to a stirred solution of bromomaleic anhydride (100 g, 565 mmol) in THF (1 l) cooled in an ice-bath so that the internal temperature did not exceed 10° C. After complete addition of the hydrazine the mixture was refluxed for 18 h. Solvent was removed by evaporation and the residues were dried by azeotroping with toluene. The residue was triturated and washed with diethyl ether to give the title compound as an orange solid (83 g, 77%). 1H NMR (250 MHz, d6-DMSO) δ 7.68 (1H, br s). MS (ES+) m/e 193 [MH]+, 191 [MH]+. This material was used without further purification.

Workup

  1. temperaturecooled in an ice-bath so that the internal temperature
  2. customdid not exceed 10° C
  3. temperaturewas refluxed for 18 h
  4. customSolvent was removed by evaporation
  5. customthe residues were dried
  6. customby azeotroping with toluene
  7. customThe residue was triturated
  8. washwashed with diethyl ether

Sources & evidence

ORD record
ord-cab6679149114e9e9ac0b5e080167282
Source dataset
uspto-grants-2004_12
Patent number
US06828322B2

Reaction notes

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