Phosphorus oxychloride → 6-Bromo-4-chlorophthalazin-1(2H)-one

Temperature

50 °C

A mixture of 6-bromo-2,3-dihydro-phthalazine-1,4-dione (42.8 g, 178 mmol) in POCl3 (300 mL) was heated at reflux for 3 h. The mixture was allowed to cool and concentrated. The residue was taken up in EtOAc (400 mL) and water (200 mL), and neutralized with sodium bicarbonate. The layers were separated, aqueous layer was extracted with EtOAc (3×200 mL), and combined organic layers were dried over anhydrous sodium sulfate and concentrated. The residue was dissolved in dioxane (300 mL) and 2N NaOH (250 mL). The mixture was heated at 50° C. for 30 min, poured into water (3 L), and stirred for 15 min. Solid was filtered and dried in vacuum at room temperature to give title compound as a greenish solid (12.0 g, 24.3%). M/z (M+1)=259.32.

1. temperaturewas heated
2. temperatureat reflux for 3 h
3. temperatureto cool
4. concentrationconcentrated
5. customThe layers were separated
6. extractionaqueous layer was extracted with EtOAc (3×200 mL)
7. dry with materialwere dried over anhydrous sodium sulfate
8. concentrationconcentrated
9. dissolutionThe residue was dissolved in dioxane (300 mL)
10. additionpoured into water (3 L)
11. filtrationSolid was filtered
12. customdried in vacuum at room temperature

ORD record

ord-f97a252204ca41ecb4ff717a6e7eba3c

Source dataset

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08349836B2