Phosphorus pentabromide → 1-Bromo-4-oxo-3,4-dihydro-phthalazine-6-carboxylic acid

HRID 1783720Notes

Reaction equation

HRID 1783720 reaction equation
O=[C:2]1[C:11]2[C:6](=[CH:7][C:8]([C:12]([OH:14])=[O:13])=[CH:9][CH:10]=2)[C:5](=[O:15])[NH:4][NH:3]1.P(Br)(Br)(Br)(Br)[Br:17]>ClCCCl.CC(O)=O>[Br:17][C:2]1[C:11]2[C:6](=[CH:7][C:8]([C:12]([OH:14])=[O:13])=[CH:9][CH:10]=2)[C:5](=[O:15])[NH:4][N:3]=1

Participants

5

Reactant 2

HCID 62678Phosphorus pentabromideHCID 3090561,4-Dioxo-1,2,3,4-tetrahydrophthalazine-6-carboxylic acid

Product 1

HCID 211065111-Bromo-4-oxo-3,4-dihydro-phthalazine-6-carboxylic acidYield 73%

Reagents, catalysts & solvents 2

HCID 111,2-DichloroethaneSolventHCID 176Acetic AcidSolvent

Procedure

1,4-Dioxo-1,2,3,4-tetrahydro-phthalazine-6-carboxylic acid (91.0 g, 0.44 mol) was suspended in DCE (1.0 L) and phosphorus pentabromide (761.0 g, 1.77 mol) was added in three portions and the reaction heated to reflux for 24 hours. The reaction was cooled to RT and poured onto ice (2.5 kg) and the resulting precipitate filtered and washed with water to give the crude product (130.0 g). This crude material was suspended in HOAc (1.6 L) and heated to 125° C. for 2 h. The reaction was cooled to RT and poured onto ice (1.5 kg) and the resulting precipitate filtered. The solid was washed with water and dried to give the title compound (85 g, 73% yield) as a yellow solid. Tr=0.94 min, m/z (ES+) (M+H)+ 310 & 312

Workup

  1. temperaturethe reaction heated
  2. temperatureto reflux for 24 hours
  3. additionpoured onto ice (2.5 kg)
  4. filtrationthe resulting precipitate filtered
  5. washwashed with water
  6. customto give the crude product (130.0 g)
  7. temperatureheated to 125° C. for 2 h
  8. temperatureThe reaction was cooled to RT
  9. additionpoured onto ice (1.5 kg)
  10. filtrationthe resulting precipitate filtered
  11. washThe solid was washed with water
  12. customdried

Sources & evidence

ORD record
ord-838951553ef546c1973ea38e16219174
Source dataset
uspto-grants-2009_03
Patent number
US07501410B2

Reaction notes

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