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

Temperature

70 °C

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).

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)

ORD record

ord-b5fe5aa2479d46078c1cb5a50d5fda4f

Source dataset

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08648194B2