3-溴咔唑的绿色合成新工艺研究

Study on the Green Novel Synthesis Method of 3-Bromocarbazole

以咔唑为原料,通过N-乙酰基保护、溴化、脱乙酰基制备出高纯3-溴咔唑。溴化体系采用溴化钠饱和溶液―浓硫酸―双氧水,考察了反应温度、双氧水用量、溴化钠用量及反应时间等因素对反应的影响。结果表明,溴化较佳工艺为N-乙酰基咔唑、溴化钠、硫酸和双氧水的物质的量比为1.0∶1.1∶0.6∶1.2,20℃反应5 h,收率90%,纯度98%。脱酰保护较佳条件为N-乙酰基-3-溴咔唑与盐酸的物质的量比为1∶10,回流反应2 h,收率97%,产品纯度为99.5%。总收率为83.8%。利用熔点和1H-NMR对各步产物进行表征。

The high purity 3-bromo-carbazole was prepared with the carbazole as raw materials, using N-acetyl protection, bromination and deacetylation. Using bromide system of saturated solution of sodium bromide-sulfuric acid-hydrogen peroxide, the reactions were examined such as temperature, amount of hydrogen peroxide, amount of sodium bromide and reaction time on the yield of reaction. The experimental results showed that the best bromide process was N- acetyl carbazole, sodium bromide,sulfuric acid and hydrogen peroxide, the molar ratio of fixed value（1.0∶1.1∶0.6∶1.2）, 20 ℃ for five hours, yield 90%, purity 98%.The best deacylation process was N- acetyl-3- bromocarbazole and hydrochloric, the molar ratio of fixed value 1∶10, refluxing for two hours, yield 90%, purity 99.5%, overall yield 83.8%. The structure of the each product was confirmed by melting point and 1H-NMR.