Hydrogen Bromide → 4-Bromo-1-ethyl-2-nitrobenzene

Temperature

-5 °C

Hydrobromic acid (48% wt. in water, 240 ml) is added dropwise to a suspension of 4-ethyl-3-nitroaniline (20 g, 0.12 mol) in water (80 ml), and the mixture stirred until the solid is dissolved. The mixture is cooled to −5° C. and a solution of sodium nitrite (19.8 g, 0.28 mol) in water (100 ml) is added dropwise, maintaining the temperature at 0-5° C. Once the addition is complete, the cooling bath is removed and the reaction mixture is stirred for one hour at room temperature. The mixture is added dropwise to a pre-cooled solution of cuprous bromide (22.4 g, 0.16 mol) in hydrobromic acid (48% wt. in water) at 0° C. The reaction mixture is stirred and allowed to warm to room temperature over three hours. The mixture is extracted with diethyl ether, and the organic extracts are combined, dried over anhydrous sodium sulfate, filtered and the filtrate concentrated in vacuo. The residue is further purified by column chromatography on silica gel, eluting with hexane to give 4-bromo-1-ethyl-2-nitrobenzene (18 g).

1. dissolutionis dissolved
2. temperaturemaintaining the temperature at 0-5° C
3. additionOnce the addition
4. customthe cooling bath is removed
5. stirringthe reaction mixture is stirred for one hour at room temperature
6. stirringThe reaction mixture is stirred
7. temperatureto warm to room temperature over three hours
8. extractionThe mixture is extracted with diethyl ether
9. dry with materialdried over anhydrous sodium sulfate
10. filtrationfiltered
11. concentrationthe filtrate concentrated in vacuo
12. customThe residue is further purified by column chromatography on silica gel
13. washeluting with hexane

ORD record

ord-ccf2738d93d64552b45d91a18f557485

Source dataset

uspto-grants-2013_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08536351B2