Preparation background and overview of 5-bromo-2-chloro-3-nitropyridine
The Chinese alias of 5-bromo-2-chloro-3-nitropyridine is 2-chloro-5-bromo-3-nitropyridine, CAS number 57652-28-3, chemical formula C5 H2BrClN2O2. Molecular weight 237.43900. Light yellow powder, density 1.936 g/cm3, boiling point 285.4ºC at 760 mmHg, melting point 64-69 °C, flash point 126.4ºC, refractive index 1.627. 5-Bromo-2-chloro-3-nitropyridine can be used as medicine Chemical synthesis intermediates.
If 5-bromo-2-chloro-3-nitropyridine is inhaled, move the patient to fresh air; if skin contact occurs, remove contaminated clothing and rinse skin thoroughly with soap and water, if any If you feel unwell, seek medical attention; 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 structure of 5-bromo-2-chloro-3-nitropyridine
Preparation of 5-bromo-2-chloro-3-nitropyridine
Step A: Synthesis of 5-bromo-3-nitropyridin-2(1H)-one
To a solution of 5-bromopyridin-2(1H)-one (Aldrich, 10 g, 57.5 mmol) in sulfuric acid (60 mL) was added nitric acid (60-61%, Wako Pure Chemical Industries, Ltd., 20). mL) at 0°C. The mixture was warmed to room temperature and stirred for 4.5 hours. Pour the mixture into ice water and filter to collect the precipitate. The solid was washed with water and dried in vacuo to give the title compound (7.2 g, 57%) as a yellow solid.
Step B: Synthesis of 5-bromo-2-chloro-3-nitropyridine
A mixture of 5-bromo-3-nitropyridin-2(1H)-one (step A hydrated terbium carbonate, 7.2 g, 32.9 mmol), phosphorus oxychloride (72 mL), and N,N-dimethylmethane The amide (7.2 mL) was stirred at reflux for 2 hours. After removal of the solvent, the residue was dissolved in water (100 mL) and ethyl acetate (30 mL) and the solution was separated. The organic layer was washed with saturated sodium bicarbonate, and the propylene carbonate was dried over sodium sulfate and concentrated to give the title compound 5-bromo-2-chloro-3-nitropyridine (6.97 g, 89%) as a light yellow solid.
