Phosphorus oxychloride → 1,6-Dichlorophthalazine

HRID 454865Notes

Reaction equation

HRID 454865 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[C:8](=O)[NH:7][N:6]=[CH:5]2.P(Cl)(Cl)([Cl:15])=O>>[Cl:15][C:8]1[C:9]2[C:4](=[CH:3][C:2]([Cl:1])=[CH:11][CH:10]=2)[CH:5]=[N:6][N:7]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 122985416-Chloro-1,2-dihydrophthalazin-1-one

Product 1

HCID 143223331,6-Dichlorophthalazine

Conditions

Temperature
105 °C

Procedure

A mixture of 6-chlorophthalazin-1(2H)-one (10.0 g, 55.4 mmol) and phosphoryl trichloride (50.0 mL, 538 mmol) was heated at 105° C. in an oil bath for 8 h. After cooling to RT, the mixture was concentrated by vacuum distillation. The brown residue was re-dissolved in CH2Cl2 and neutralized with saturated aq. NaHCO3. After stirring for 3 h, the organic layer was collected and the aqueous layer was extracted with CH2Cl2 (3×). The combined organics were dried over Na2SO4, filtered through a pad of silica gel, eluting with EtOAc, and concentrated to give the title compound as a tan solid. MS (ESI, pos. ion) m/z: 199.0 (M+1).

Workup

  1. temperatureAfter cooling to RT
  2. concentrationthe mixture was concentrated by vacuum distillation
  3. dissolutionThe brown residue was re-dissolved in CH2Cl2 and neutralized with saturated aq. NaHCO3
  4. customthe organic layer was collected
  5. extractionthe aqueous layer was extracted with CH2Cl2 (3×)
  6. dry with materialThe combined organics were dried over Na2SO4
  7. filtrationfiltered through a pad of silica gel
  8. washeluting with EtOAc
  9. concentrationconcentrated

Sources & evidence

ORD record
ord-b7c5252a051444239c75ba41f10f4b04
Source dataset
uspto-grants-2013_07
Patent number
US08497269B2

Reaction notes

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