Background: Nitroaromatic compounds are important scaffolds used for the syn-thesis of a variety of compounds, such as explosives, herbicides, dyes, perfumes and phar-maceuticals. Bismuth nitrate pentahydrate is a widely used reagent in organic synthesis; how-ever, its utility as a nitrating agent for anilines is underexplored. Objective: The aim of this work is to propose and find the proper reaction conditions of an alternative nitrating agent constituted by a mixture of bismuth nitrate / acetic anhydride in DCM with a series of substituted anilines under mild reflux. Methods: Several anilines having both activating and deactivating substituents in the ortho, meta and para positions were the substrate for the nitration reaction. Experimental conditions were performed in “one-pot” conditions before product purification. Results: Bi(NO3)3•5H2O demonstrated to be effective and somehow regioselective when it came to the nitration of anilines in the ortho position. Although other products were also identified under these conditions, in most cases, the ortho derivative was the major or even the only product obtained with moderate to high yields in the range of 50% – 96%. Conclusion: Bi(NO3)3•5H2O is an efficient and safe nitrating agent since the use of concen-trated and corrosive acids like sulfuric and nitric is avoided; furthermore, bismuth nitrate is low-priced and no special care nor equipment is required.

中文翻译：

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用五水硝酸铋选择性合成邻硝基苯胺的替代方法

背景：硝基芳香族化合物是用于合成多种化合物的重要支架，如炸药、除草剂、染料、香料和药物。五水硝酸铋是有机合成中广泛使用的试剂；然而，其作为苯胺硝化剂的用途尚未得到充分研究。目的：本工作的目的是提出并找到由硝酸铋/乙酸酐在 DCM 中的混合物与一系列取代苯胺在温和回流下组成的替代硝化剂的适当反应条件。方法：几种在邻位、间位和对位均具有活化和失活取代基的苯胺作为硝化反应的底物。实验条件在产物纯化之前在“一锅”条件下进行。结果：Bi(NO3)3•5H2O 在邻位苯胺的硝化中被证明是有效的且具有一定的区域选择性。虽然在这些条件下也鉴定出了其他产物，但在大多数情况下，邻位衍生物是主要甚至是唯一获得的产物，收率在50%至96%之间的中等到高产率。结论：Bi(NO3)3•5H2O避免使用硫酸、硝酸等浓酸和腐蚀性酸，是一种高效、安全的硝化剂；此外，硝酸铋价格低廉，无需特殊护理或设备。