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ChemicalBook CAS DataBase List 2-Bromo-4-methylpyridine
4926-28-7

2-Bromo-4-methylpyridine synthesis

5synthesis methods
4-Methylpyridin-2-amine

695-34-1

2-Bromo-4-methylpyridine

4926-28-7

The general procedure for the synthesis of 2-bromo-4-methylpyridine from 2-amino-4-methylpyridine was as follows: 2-amino-4-methylpyridine (120 g, 1.1 mol) was dissolved in 48% hydrobromic acid (1.5 L) and bromine (160 mL, 3.11 mol) was added slowly and dropwise at -20 °C. The reaction mixture was stirred continuously for 3 hours at -15°C to -20°C. Subsequently, aqueous sodium nitrite (NaNO2) (204 g, 2.95 mol) was added to the reaction system in batches. The reaction mixture was gradually warmed up to room temperature over a period of 3 hours. A 20% aqueous sodium hydroxide (NaOH) solution (1.2 Kg NaOH dissolved in 2 L of water) was added and the pH was adjusted to 12 while the temperature was controlled at 0 °C. The reaction mixture was extracted with ether (3 x 250 mL), the organic phase was washed sequentially with water and saturated brine and dried anhydrous. After removing the solvent under reduced pressure, the reaction was purified by fractional distillation to afford 2-bromo-4-methylpyridine (164 g, 86% yield) as a light yellow liquid.

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Yield:-

Steps:

5.1 Step 1
Step 1 2-Bromo-4-bromomethyl pyridine Following the procedure of Adams et.al. (J. Am. Chem. Soc., 76, 3168 (1954)) 2-bromo-4-methylpyridine was obtained from 2-amino-4-methylpyridine. 1 H-NMR (CDCl3): 2.3 ppm (s, 3H); 7.05 ppm (d, 1H); 7.3 ppm (s, 1H); 8.2 ppm (s, 1H).

References:

Merck & Co., Inc. US6127390, 2000, A

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