A Simple Key for Benzylic Mono- and <b><i>gem</i></b>-Dibromination of Primary Aromatic Amine Derivatives Using Molecular Bromine
作者:Narshinha Argade、Anirban Kar
DOI:10.1055/s-2002-19812
日期:——
Quantitative benzylic mono- and gem-dibromination on primary aromatic amine derivatives have been achieved using molecular bromine and by protecting the amino group as a succinimide moiety. The reactions of N-(o/m/p-tolyl)succinimides 5a-c with 1.25 equivalents of molecular bromine in CCl4 at room temperature furnished the corresponding benzylic monobrominated products 6a-c in 92-94% yields, while with 2.5 equivalents of molecular bromine in refluxing CCl4 gem-dibromo products 7a-c were obtained in 94-96% yields. It is also possible to carry out nuclear bromination in these N-protected primary aromatic amines at an alternate site by using suitably substituted aniline derivatives. Thus the reaction of 3 with 1.25 equivalents of molecular bromine in acetic acid gave the desired monobrominated product 4 in nearly 100% yield.
通过使用分子溴并将氨基保护为琥珀酰亚胺基团,实现了对芳香胺衍生物的定量苄位单溴化和双溴化。在室温下,N-(邻/间/对甲苯基)琥珀酰亚胺5a-c与1.25当量的分子溴在四氯化碳中反应,以92-94%的产率得到了相应的苄位单溴化产物6a-c,而在回流的四氯化碳中与2.5当量的分子溴反应,则以94-96%的产率得到了双溴化产物7a-c。通过使用适当取代的苯胺衍生物,也可以在这些N-保护的芳香胺中其他位点进行核溴化。因此,3与1.25当量的分子溴在乙酸中反应,几乎以100%的产率得到了所需的单溴化产物4。