Hydrochloric Acid → 2-Bromo-4-isopropylaniline

Temperatur

50 °C

A mixture of 99 g (0.73 mol) of 4-isopropylaniline (Acros) and 300 ml of acetic acid was refluxed for 1 h; then, 75 g of acetic anhydride was added dropwise while vigorously stirring. The resulting solution was cooled to 50° C., and 37.4 ml of bromine was added dropwise, while vigorously stirring, over ca. 30 min. Then, 370 ml of 12 M HCl was added and this mixture was refluxed until a precipitate was formed. This precipitate was separated, washed with 2×150 ml of methyl-tert-butyl ether, and dried in vacuum. A mixture of the solid obtained and a solution of 112 g of KOH in 300 ml of water was stirred at 50-60° C. for 1 h. The organic layer was separated, and the aqueous layer was extracted with 2×150 ml of methyl-tert-butyl ether. The combined extract was dried over K2CO3 and evaporated to dryness. Fractional distillation gave the title product, b.p. 107-111° C./3 mm Hg. Yield 83.7 g (77%) of yellowish oil.

1. temperaturewas refluxed for 1 h
2. stirringwhile vigorously stirring, over ca. 30 min
3. temperaturethis mixture was refluxed until a precipitate
4. customwas formed
5. customThis precipitate was separated
6. washwashed with 2×150 ml of methyl-tert-butyl ether
7. customdried in vacuum
8. additionA mixture of the solid
9. customobtained
10. customThe organic layer was separated
11. extractionthe aqueous layer was extracted with 2×150 ml of methyl-tert-butyl ether
12. extractionThe combined extract
13. dry with materialwas dried over K2CO3
14. customevaporated to dryness
15. distillationFractional distillation

ORD-Eintrag

ord-f9534332412b40a08b2ab7d09c5ad8b9

Quelldatensatz

uspto-grants-2008_11

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07446216B2