Hydrogen Bromide → 2-Bromo-3-nitrotoluene

Temperature

15 °C

A stirred solution of 75.0 grams (0.493 mole) of 2-methyl-6-nitroaniline and 40 ml of aqueous 48% hydrobromic acid in 135 ml of water was cooled to 0° C. and a solution of 36.2 grams (0.510 mole) of sodium nitrate in 60 ml of water was added dropwise during a one hour period. Upon complete addition the mixture was filtered through glass wool into a large dropping funnel. This solution was added dropwise to a second solution of 77.8 grams (0.542 mole) of cuprous bromide in 165 ml of aqueous 48% hydrobromic acid that was being stirred at 15° C. Upon complete addition the reaction mixture was stirred at 15° C. for a few minutes then was allowed to warm to ambient temperature where it stirred for one hour. The reaction mixture stood for 16 hours then was heated to 60° C. where it stirred for two hours. The reaction mixture was subjected to steam distillation. The distillate was extracted with three portions of 150 ml each of methylene chloride. The combined extracts were washed with two portions of 150 ml each of aqueous 2 N sodium hydroxide and five portions of 200 ml each of an aqueous solution saturated with sodium chloride (until the wash was pH-7). The organic layer was dried with magnesium sulfate while being slurried with decolorizing carbon. The mixture was filtered and the filtrate concentrated under reduced pressure to give 6.6 grams of 2-bromo-3-nitrotoluene; mp 36°-41° C. The nmr spectrum was consistent with the proposed structure. The pot residue from the steam distillation was extracted with 400 ml of methylene chloride. The extract was washed with aqueous 2 N sodium hydroxide then with an aqueous solution saturated with sodium chloride (until the salt wash was pH-7). The organic layer was dried with magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure to give 18.0 grams of 2-bromo-3-nitrotoluene, which was combined with the 6.6 grams of above to give a total yield of 24.6 grams.

1. additionUpon complete addition the mixture
2. filtrationwas filtered through glass wool into
3. additionUpon complete addition the reaction mixture
4. stirringwas stirred at 15° C. for a few minutes
5. temperatureto warm to ambient temperature where it
6. stirringstirred for one hour
7. temperaturethen was heated to 60° C. where it
8. stirringstirred for two hours
9. distillationThe reaction mixture was subjected to steam distillation
10. extractionThe distillate was extracted with three portions of 150 ml each of methylene chloride
11. washThe combined extracts were washed with two portions of 150 ml each of aqueous 2 N sodium hydroxide and five portions of 200 ml each of an aqueous solution saturated with sodium chloride (until the wash
12. dry with materialThe organic layer was dried with magnesium sulfate
13. filtrationThe mixture was filtered
14. concentrationthe filtrate concentrated under reduced pressure

ORD record

ord-4bb3e886f224405aa767eb515405f6e6

Source dataset

uspto-grants-1982_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04339457