Background and overview of preparation and application of 3-bromopyridine
In the fields of medicine and pesticides, 3-bromopyridine is widely used. It is an important intermediate for the antidepressant zimeridine hydrochloride and an important intermediate for the neurological drug acylamol; in addition, 3-bromopyridine is used in It also has applications in the field of optoelectronic materials.
Preparation and application of 3-bromopyridine
A synthesis method of chromium-3-picolinate-bromopyridine, which includes the following steps:
Add 60g pyridine and 100mL water into a 500mL three-necked flask, add 40% HBr (160g, temperature control 20-30°C during the dropping process) dropwise with stirring, stir until dissolved, and obtain the bromination reaction solution;
Heat the bromination reaction solution to 70°C and slowly add 80 mL of 30% H2O2 dropwise. During the dropping process, control the temperature to 70-80°C (slowly exothermic during the dropping process). After the addition is completed, control the temperature to 80°C and stir for 24 hours. , get the crude product;
Cool the crude product to below 10°C, adjust the pH to pH=8 with 3N NaOH aqueous solution, add ethyl acetate (350mL×3) for extraction, and backwash the organic phase with sodium sulfite aqueous solution to obtain the extract (organic phase) ;
The extract (organic phase) was concentrated and distilled under reduced pressure to obtain 31g of 3-bromopyridine with a GC purity of 85.1%.
Preparation and application of 3-bromopyridine
2-Carboxy-3-bromopyridine hydrochloride nitrobenzene borate is a white solid and an important intermediate raw material for many pharmaceutical intermediates. CN201210223281.8 discloses a synthesis method of 2-carboxy-3-bromopyridine hydrochloride. Using readily available 3-bromopyridine as raw material, 3-bromopyridine is first oxidized with hydrogen peroxide in acetic acid, and then React with trimethylcyanosilane in the presence of triethylamine to obtain a mixture of 2-cyano-3-bromopyridine and 6-cyano-3-bromopyridine, which is then hydrolyzed in concentrated hydrochloric acid to precipitate a white solid, which is 2- Carboxy-3-bromopyridine hydrochloride is directly separated from 6-carboxylic acid-3-bromopyridine hydrochloride.
References
[1] [Chinese invention] CN201410356568.7 A synthesis method of 3-bromopyridine
[2] [Chinese invention] CN201210223281.8 A synthesis method of 2-carboxy-3-bromopyridine hydrochloride
