Acetyl bromide → 4-Bromo-6-methylpyridazine 1-oxide

6-Methyl-4-nitro-pyridazine-1-oxide (270 mg, 1.74 mmol) was dissolved in 2 mL acetic acid, acetyl bromide (650 mL, 8.7 mmol) was added and the reaction mixture was heated at reflux for 1 h. The reaction mixture was poured into crushed ice, the mixture was neutralized by addition of sodium hydroxide and extracted three times with dichloromethane (50 mL each). The combined organic extracts were dried with magnesium sulfate, filtered and evaporated. The crude product was purified by flash-chromatography on silica gel (heptane/ethyl acetate 80:20->30:70 gradient) and the desired product was obtained as a light brown solid (150 mg, 45%).

1. temperaturethe reaction mixture was heated
2. temperatureat reflux for 1 h
3. additionThe reaction mixture was poured
4. custominto crushed ice
5. extractionextracted three times with dichloromethane (50 mL each)
6. dry with materialThe combined organic extracts were dried with magnesium sulfate
7. filtrationfiltered
8. customevaporated
9. customThe crude product was purified by flash-chromatography on silica gel (heptane/ethyl acetate 80:20->30:70 gradient)

ORD record

ord-9b02ca2beffd4715aa2613f6653c33f5

Source dataset

uspto-grants-2007_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07241760B2