The (E) and (Z) isomers of α bromo 2 hydroxy-4-nitrochalcone both exhibited the unusual ability to undergo nucleophilic addition to the α position of the double bond. They differed markedly, however, in their preferred mode, the former favoured α addition, the latter β addition. It is proposed that these isomers are intermediates in the Emilewicz-von Kostanecki cyclization of 2 hydroxy-4-nitrochalcone
αbromo 2羟基-
4-硝基查耳酮的(E)和(Z)异构体均显示出非寻常的能力,可进行亲核加成至双键的α位。它们明显不同,但是,在它们的优选方式中,前者偏爱α加成,后者偏爱β加成。提出这些异构体是2-羟基-
4-硝基查尔酮二
溴化物在Emilewicz-von Kostanecki环化成
金酮和
黄酮的混合物中的中间体。