Hydrogen Bromide → 2-Amino-5-bromo-4-methylpyridine

Temperature

70 °C

2-Amino-4-methylpyridine (110 g, 1.02 mol) in hydrobromic acid (1 L, 48%) was stirred at 70° C. and a solution of hydrogen peroxide (300 mL, 15%) was added dropwise over a one h at such a rate that the temperature of the reaction mixture remained at 70-80° C. The mixture was stirred for 90 min at 70° C. and poured onto crushed ice. The pH was adjusted to 4-5 with sodium carbonate and the precipitated solid (containing mostly dibrominated products) was filtered off and discarded. The pH was subsequently raised to 9 and the precipitated product collected by filtration. Recrystallization from toluene gave 2-Amino-5-bromo-4-methylpyridine (76.3 g, 40%).

1. customremained at 70-80° C
2. additionpoured
3. customonto crushed ice
4. additionthe precipitated solid (containing mostly dibrominated products)
5. filtrationwas filtered off
6. temperatureThe pH was subsequently raised to 9
7. filtrationthe precipitated product collected by filtration
8. customRecrystallization from toluene

ORD record

ord-9c5095105cfe4857aa00178cf8638848

Source dataset

uspto-grants-2006_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07071175B1