ChemicalBook CAS DataBase List 4-Bromo-2-methylpyridine

4-Bromo-2-methylpyridine synthesis

11synthesis methods

Product Name:4-Bromo-2-methylpyridine
CAS Number:22282-99-1
Molecular formula:C6H6BrN
Molecular Weight:172.02

18437-58-6

22282-99-1

2-Methyl-4-aminopyridine (152) (10.1 g, 93.4 mmol) was used as a raw material, which was dissolved in 48% aqueous hydrobromic acid (165 mL) at -10°C and stirred to form a solution. An aqueous solution of sodium nitrite (7.04 g, 0.102 mol) pre-cooled to 0°C (165 mL) was added dropwise to this solution over a period of 0.5 hours. After the dropwise addition, the reaction mixture was slowly warmed to room temperature and stirring was continued for 16 hours. Upon completion of the reaction, the reaction mixture was diluted with 4 M sodium hydroxide solution (400 mL) and subsequently extracted with tert-butyl methyl ether (TBME). All TBME phases were combined, dried with anhydrous magnesium sulfate and finally concentrated under vacuum to give the target product 4-bromo-2-methylpyridine (153). Yield: 14.8 g (92% yield).LC/MS analysis: retention time 0.57 min, mass spectrum (ES+) m/z 172, 174 ([M+H]+).

18437-58-6
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22282-99-1
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Yield:22282-99-1 95%

Reaction Conditions:

with hydrogen bromide;bromine at -5;

Steps:

1.3 (3) Preparation of 2-methyl-4-bromopyridine:
2-Methyl-4-aminopyridine (10.8 g, 0.1 mol) was added to 48% HBr (46 ml, 0.4 mol) with ice-cooling.After the addition is completed, the mixture is cooled to -5 ° C, and liquid bromine (15 ml, 0.3 mol) is slowly added dropwise, and the addition is completed in 30-35 minutes.Then, 42% of a 40% sodium nitrite solution was added dropwise at 0 ° C or less, and the addition was completed in 1-1.1 h.After the addition is completed, the mixture is stirred at 0 ° C for 30 min, and then slowly added with 50% sodium hydroxide solution below 20 ° C to adjust the pH of the solution to 9,The reaction solution was extracted with ethyl acetate, dried over anhydrous sodium sulfate grassroots, suction filtered, and concentrated2-Methyl-4-bromopyridine was obtained in a molar yield of 95%.

References:

Danyang Ning David Fang To Detect Co., Ltd.;Wei Qian CN109748854, 2019, A Location in patent:Paragraph 0018; 0021

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