Phosphorus oxychloride → 4-Chloro-1,5-dimethyl-6-oxo-1,6-dihydropyridazine-3-carboxylic acid

HRID 15970Notes

Reaction equation

HRID 15970 reaction equation
O[C:2]1[C:3]([C:11]([OH:13])=[O:12])=[N:4][N:5]([CH3:10])[C:6](=[O:9])[C:7]=1[CH3:8].O=P(Cl)(Cl)[Cl:16]>>[Cl:16][C:2]1[C:3]([C:11]([OH:13])=[O:12])=[N:4][N:5]([CH3:10])[C:6](=[O:9])[C:7]=1[CH3:8]

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 574421684-Hydroxy-1,5-dimethyl-6-oxo-1,6-dihydropyridazine-3-carboxylic acid

Product 1

HCID 666732574-Chloro-1,5-dimethyl-6-oxo-1,6-dihydropyridazine-3-carboxylic acidYield 60%

Conditions

Temperature
85 °C

Procedure

A mixture of 4-hydroxy-1,5-dimethyl-6-oxo-1,6-dihydropyridazine-3-carboxylic acid (876 mg, 4.76 mmol) and POCl3 (4.5 mL) was heated for 24 hours at 85° C. POCl3 was removed under reduced pressure. The crude material was quenched with ice. The reaction mixture was stirred for 1 hour at room temperature. After removing solids by filtration, the aqueous filtrate was extracted with EtOAc (3×). The combined organic layers were dried over MgSO4, filtered, and concentrated under reduced pressure to give. The recovered material was combined with the solids previously isolated and triturated with ether to afford 577 mg (60%) of the desired product.

Workup

  1. customPOCl3 was removed under reduced pressure
  2. customThe crude material was quenched with ice
  3. customAfter removing solids
  4. filtrationby filtration
  5. extractionthe aqueous filtrate was extracted with EtOAc (3×)
  6. dry with materialThe combined organic layers were dried over MgSO4
  7. filtrationfiltered
  8. concentrationconcentrated under reduced pressure
  9. customto give
  10. custompreviously isolated
  11. customtriturated with ether

Sources & evidence

ORD record
ord-c71b32b0448d43e49c84e64943d86824
Source dataset
uspto-grants-2010_06
Patent number
US07732616B2

Reaction notes

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