Acetyl bromide → HCID 22317679, compound

2-Ethyl-6-methyl-4-nitropyridine N-oxide (36.4 g) was added to 60 g of acetic acid and the mixture was warmed to give a clear solution which was cooled to 15°-20° C. and treated dropwise, keeping the temperature below 25° C., with 49.2 g of acetyl bromide. After addition was complete, the mixture was stirred at room temperature for 11/2 hours and then slowly warmed to 65°-70° C. and kept in this temperature range for 24 hours. The acetic acid and volatile components were removed in vacuo and 200 ml of chloroform were added to the residue. To the chilled mixture there was added dropwise 58 g of phosphorus tribromide at 10° C. and the mixture was warmed to room temperature and then heated at reflux for 3 hours. An additional 10 g of phosphorus tribromide were added and the mixture was heated for 1 hour, poured onto ice, neutralized with cold 35% sodium hydroxide and extracted three times with 200 ml of methylene chloride. The organic extract was concentrated, 300 ml of diethyl ether were added and the ether solution was dried over magnesium sulfate and concentrated. The crude product was fractionated in vacuo to give 30 g of the title product as a yellow oil; bp13 120°-130° C.

1. temperaturethe mixture was warmed
2. customto give a clear solution which
3. temperaturewas cooled to 15°-20° C.
4. additiontreated dropwise
5. customthe temperature below 25° C.
6. additionAfter addition
7. temperatureslowly warmed to 65°-70° C.
8. waitkept in this temperature range for 24 hours
9. customThe acetic acid and volatile components were removed in vacuo and 200 ml of chloroform
10. additionwere added to the residue
11. additionTo the chilled mixture there was added dropwise 58 g of phosphorus tribromide at 10° C.
12. temperaturethe mixture was warmed to room temperature
13. temperatureheated
14. temperatureat reflux for 3 hours
15. additionAn additional 10 g of phosphorus tribromide were added
16. temperaturethe mixture was heated for 1 hour
17. additionpoured onto ice, neutralized with cold 35% sodium hydroxide
18. extractionextracted three times with 200 ml of methylene chloride
19. extractionThe organic extract
20. concentrationwas concentrated
21. addition300 ml of diethyl ether were added
22. dry with materialthe ether solution was dried over magnesium sulfate
23. concentrationconcentrated

ORD record

ord-5125cb73c053434b89e2dd7d92f24372

Source dataset

uspto-grants-1994_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05308843