Background and overview of preparation and application examples of 2-bromo-5-nitropyridine
2-Bromo-5-nitropyridine nitrobenzene boronic acid is an off-white to light yellow crystal and is used in the synthesis of pharmaceutical intermediates. 2-Bromo-5-nitropyridine can be prepared from 2-hydroxy-5-nitropyridine through bromination reaction. There are reports in the literature that it can be used to prepare 2-cyano-5-hydroxypyridine.
Preparation and application examples of 2-bromo-5-nitropyridine
A mixture of 1.53 g (10.94 mmol) 2-hydroxy-5-nitropyridine, 4.1 g (12.71 mmol) tetrabutylammonium bromide and 3.71 g (26.1 mmol) P2O5 in 29 ml benzene Heat and stir at reflux for 1 hour. The mixture was cooled to room temperature, the upper layer was separated by decantation, and the lower layer was triturated with benzene (3 x 6 ml). The extracts were combined with the organic phase, washed with saturated NaHCO3 and NaCl solutions, and dried over MgSO4. The solvent was distilled off under reduced pressure, and the residue was recrystallized from petroleum ether. Yield 1.7 g (48%). Mp 138- 139°C, (bp 40-70°C).
Preparation and application examples of 2-bromo-5-nitropyridine
CN201710234455.3 reports a preparation method of 2-cyano-5-hydroxypyridine. This method uses 2-bromo-5-nitropyridine, NaCN, CuCN, dimethylformamide and KH2PO4 as starting materials to first generate 2-cyano-5-nitropyridine; then add ethyl acetate and An appropriate amount of Fe cyclopentopyridine powder is reduced, and a sufficient amount of acetic acid is added; finally, an appropriate amount of H2SO4 solution and NaNO2 are added, filtered and dried to finally obtain orange solid 2-cyano-5-hydroxypyridine. This method has easy-to-obtain raw materials, mild reaction conditions, low cost, and is suitable for large-scale factory production.
References
[1] Russian Journal of Organic Chemistry, 46(12), 1830-1834; 2010
[2] Preparation method of CN201710234455.32-cyano-5-hydroxypyridine
