Synthesis of N -Ester Carbazoles Using Diethyl Azodicarboxylate as Carbon Source

A novel strategy for the N-acylation of secondary arylamines using diethyl azodicarboxylate (DEAD) as the carbon source under base promotion is presented.Carbazole compounds and DEAD were utilized as substrates, affording a series of diverse N-ester carbazole compounds in 15%～94% yields.This approach proceeds under transition metal-free conditions, and offers the advantages of commercially available and inexpensive starting materials, green and mild reaction conditions, operational simplicity, broad substrate scope, and short reaction times.It provides a convenient method for the simple and efficient synthesis of N-substituted carbazoles.The practical application of this method was demonstrated by the gram-scale (10 mmol) synthesis and product derivatizations.Investigation of reaction mechanism suggests that the reaction proceeds via deprotonation of carbazole under basic conditions, followed by nucleophilic attack of the resulting nitrogen anion on DEAD, and subsequent elimination.Keywords carbazole; N-acylation; diethyl azodicarboxylate 杂环化合物是一类碳环中嵌入氮、氧或硫等杂原子 的有机化合物, 广泛存在于自然界中, 尤其在生物活性 分子中占据重要地位 [1] .在众多的杂环分子库中, 咔唑 及其衍生物由于其独特的分子结构, 在光电材料、 医药、 有机配体和染料等领域得到了广泛应用 [2] .尤其在医药 领域、多种天然产物和商品化的药物中, 都存在咔唑骨 架(Scheme 1).例如九里香碱(Murrayanine)具有良好的 抗肿瘤特性 [3] ; 艾乐替尼(Alectinib)是一种间变性淋巴