A new series of indeno[1,2-b]indol-5(4bH)-ylbenzimidamide derivatives 3a–3j has been synthesized as potential casein kinase II (CK2) inhibitors. A convenient and straightforward synthesis protocol was used via a reaction of β-enaminones 1a–1j with ninhydrin 2. This transformation proceeds under mild conditions (boiling ethanol, 0.5 h) in absence of catalyst in good to excellent yields (66–86%). The new compounds have been characterized by NMR, HRMS and IR spectra.

中文翻译：

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Indeno[1,2-b]indol-5(4bH)-yl benzimidamides 的无催化剂直接合成

一个新系列的 indeno[1,2-b]吲哚-5(4bH)-ylbenzimidamide 衍生物 3a–3j 已被合成为潜在的酪蛋白激酶 II (CK2) 抑制剂。使用方便直接的合成方案通过的反应β- 烯胺酮 1a–1j 与茚三酮 2。这种转化在温和条件下（沸腾乙醇，0.5 小时）在没有催化剂的情况下进行，产率从好到极好 (66–86%)。新化合物已通过 NMR、HRMS 和 IR 光谱进行了表征。