Preparation of 3-amino-4,6-dibromopyridine_Industrial additives

Preparation background and overview of 3-amino-4,6-dibromopyridine

3-Amino-4,6-dibromopyridine can be used as a pharmaceutical synthesis intermediate. If 3-amino-4,6-dibromopyridine is inhaled, please move the patient to fresh air; if there is skin contact, take off contaminated clothing, wash the skin thoroughly with soap and water, and seek medical treatment if you feel uncomfortable; If eye contact occurs, separate eyelids, rinse with running water or saline, and seek medical attention immediately; if ingested, rinse mouth immediately, do not induce vomiting, and seek medical attention immediately.

Preparation of 3-amino-4,6-dibromopyridine

The preparation of 3-amino-4,6-dibromopyridine is as follows: at 0-5°C, add sodium bromide (21.87g, 212.4mmol) and sodium bromate (63.76g, 425.0mmol) in ( ml) in water was added to a solution of pyridin-3-amine (20.0 g, 0.213 mol) in acetonitrile (200 ml). Then, with cooling, sulfuric acid (prepared from 20.84g (212.5mmol) of concentrated sulfuric acid and 200ml of water) was added within 30 minutes. The mixture was stirred at 5°C for 1 h and filtered, and the residue was washed with saturated NaHCO3 solution (200 ml) and water (200 ml) and dried under reduced pressure. 40.0 g (amount of constant methoxypyridine) of crude product 3-amino-4,6-dibromopyridine was obtained.

Basic zinc carbonate

Preparation and application of 3-amino-4,6-dibromopyridine

3-Amino-4,6-dibromopyridine can be used as a pharmaceutical synthesis intermediate. If the following reaction occurs; add oxalyl chloride (61.86g, 487.4mmol) and dimethylformamide (1.19g, 16.3mmol) to a solution of pyridine-3-carboxylic acid (20.00g, 162.5mmol) in CH2Cl2 (200ml) . The mixture was stirred at room temperature for 3 h, then the solvent was removed under reduced pressure. The acid chloride obtained was dissolved in CH2Cl2 (100 ml). 3-Amino-4,6-dibromopyridine (40.9g, 164mmol) was dissolved in CH2Cl2 (200ml) and triethylamine (49.3g, 487mmol) was added. The mixture was stirred at room temperature for 10 min, then the acid chloride solution was slowly added. The reaction mixture was stirred at room temperature for 16 h, the solvent was removed under reduced pressure and the residue was chromatographed on silica gel (gradient: ethyl acetate/petroleum ether: 50:50→75:25) by column chromatography. 20.0 g (yield 34%) of N-(4,6-dibromo-3-pyridyl)pyridine-3-carboxamide were obtained.