Phosphorus oxybromide → 2,9-Dibromo-1,10-phenanthroline

HRID 716560Notes

Reaction equation

HRID 716560 reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][C:5]2[C:14]([N:15]=1)=[C:13]1[C:8]([CH:9]=[CH:10][C:11](=O)[N:12]1C)=[CH:7][CH:6]=2.P(Br)(Br)([Br:20])=O.P(Cl)(Cl)(Cl)(Cl)Cl>>[Br:20][C:11]1[CH:10]=[CH:9][C:8]2[C:13](=[C:14]3[C:5](=[CH:6][CH:7]=2)[CH:4]=[CH:3][C:2]([Br:1])=[N:15]3)[N:12]=1

Participants

4

Reactant 3

HCID 24613Phosphorus oxybromideHCID 24819Phosphorus pentachlorideHCID 713604359-Bromo-1-methyl-1,10-phenanthrolin-2(1H)-one

Product 1

HCID 154480992,9-Dibromo-1,10-phenanthrolineYield 81.3%

Conditions

Temperature
70 °C

Procedure

Under a stream of argon, to compound (9) (8.4 g; 29.1 mmol), phosphorus oxybromide (3.25 g; 174 mmol) and phosphorus pentachloride (15.4 g; 35.8 mmol) were added in an ice bath. The reaction temperature was raised to 65 to 75° C., and the resulting reaction mixture was stirred for 5.5 hours. The reaction mixture was cooled in an ice bath and evaporated under reduced pressure. Excess phosphorus oxybromide was removed and the resulting reaction concentrate was poured into ice water, and was made alkaline with concentrated aqueous ammonia. While solids which precipitated out were separated by filtration, they were washed with water to give crude title compound (10). The crude compound (10) was dried, and separated and purified by silica gel column chromatography (SiO2 300 g) (CHCl3/methanol=50/1 to 40/1 to 30/1) to give 8 g (yield: 81%) of the title compound (10).

Workup

  1. customthe resulting reaction mixture
  2. temperatureThe reaction mixture was cooled in an ice bath
  3. customevaporated under reduced pressure
  4. customExcess phosphorus oxybromide was removed
  5. customthe resulting reaction
  6. concentrationconcentrate
  7. additionwas poured into ice water
  8. customWhile solids which precipitated out
  9. customwere separated by filtration, they
  10. washwere washed with water
  11. customto give crude title compound (10)
  12. dry with materialThe crude compound (10) was dried
  13. customseparated
  14. custompurified by silica gel column chromatography (SiO2 300 g) (CHCl3/methanol=50/1 to 40/1 to 30/1)

Sources & evidence

ORD record
ord-8206e36af6a84372be063b06edb44cba
Source dataset
uspto-grants-2015_11
Patent number
US09187690B2

Reaction notes

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