5-bromo-4-methyl-2-nitropyridine synthesis

Yield:1225278-70-5 68.95%

Reaction Conditions:

with sulfuric acid;dihydrogen peroxide at -20 - 30; for 0.75 h;Inert atmosphere;

Steps:

33.1 5-bromo-4-methyl-2-nitropyridine

Step 1
5-bromo-4-methyl-2-nitropyridine
H₂O₂ (58.06 g, 1.71 mol, 21.28 equivalents) was slowly added dropwise to H₂SO₄ (184.00 g, 1.88 mol, 23.39 equivalents) which was cooled to 0°C, and the temperature was maintained below -20°C during the dropwise addition.
A mixture of 5-bromo-4-methylpyridine-2-amine (15.00 g, 80.20 mmol, 1.00 equivalent) in H₂SO₄ (100,00 mL) was then added thereto.
The reaction mixture was first stirred for 45 minutes in an ice bath and then warmed to 30°C.
After three hours, the color of the reaction solution changed gradually from grass green to bright yellow.
Ice (500 mL) was added to the reaction mixture.
The precipitated solid was filtered, washed with water and then dried in vacuo to give the title compound (12.00 g, 55.29 mmol, 68.95% yield) as a bright orange solid without further purification. LC/MS (ESI) m/z: 216.9 (M+1), 218.9 (M+3).

References:

EP3269715,2018,A1 Location in patent:Paragraph 0061; 0366; 0367