Ditercalinium (NSC 366241) is a 7H-pyrido[4,3-c]carbazole dimer with a diethylbipiperidine rigid chain linking the two heterocyclic rings. Ditercalinium is characterized by a high DNA affinity and bisintercalating ability, associated with potent antitumor properties, involving an original mechanism of action. Unfortunately as ditercalinium is hepatotoxic, its clinical evaluation has been interrupted. In order to eliminate or at least minimize the serious drawbacks related to its toxic effects, several chemical modifications have been made to the structure of ditercalinium, and their influence has been evaluated by measuring the DNA affinities, intercalation properties, and toxicity toward leukemia cells of the newly synthesized dimers. Reduction of the pyridinic moieties of ditercalinium, in order to suppress the permanent charges provided by the quaternizing chain, led to an almost complete loss of activity, although the DNA bisintercalating property of the dimer was preserved. Dimerization of the 7H-pyrido[4,3-c]carbazole rings by introduction of the rigid spacer on the N7- or C6-positions corresponding to the convex face of the pyridocarbazole, instead of the N2-position in ditercalinium, led to DNA bisintercalating dimers practically devoid of antitumor properties. However after quaternarization of the N2 atoms, the dimer linked by the N7 atoms exhibited a very high DNA affinity (greater than 10(9) M-1) and recovered antitumor activity, supporting the requirement of positive charges for the emergence of antitumor activity in these dimers. Introduction on the C6 of the 7H-pyridocarbazole ring of an aminomethyl or carboxyl group, a sugar residue, or C or N free amino acids such as Lys or Glu has also been carried out, in order to increase the hydrophilic properties of the molecules or to enable them to use amino acid transport systems. Although some of these compounds were active, none of them exhibited the pharmacological potency of ditercalinium.

中文翻译：

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7H-吡啶并[4,3-c]咔唑抗肿瘤系列新二聚体的合成及生物活性。

Ditercalinium（NSC 366241）是7H-吡啶并[4,3-c]咔唑二聚体，其二乙基联哌啶刚性链连接两个杂环。Ditercalinium的特点是具有高的DNA亲和力和双嵌入能力，并具有强大的抗肿瘤特性，涉及原始的作用机理。不幸的是，由于二钙cali具有肝毒性，因此其临床评估已中断。为了消除或至少最小化与其毒性作用有关的严重缺陷，已对二萜的结构进行了几种化学修饰，并通过测量DNA亲和力，嵌入性质和对白血病细胞的毒性来评估其影响。新合成的二聚体。还原二cali的吡啶部分，为了抑制由季铵化链提供的永久电荷，尽管保留了二聚体的DNA双插入性质，但导致活性几乎完全丧失。通过在与吡啶并咔唑的凸面相对应的N7-或C6位置上引入刚性间隔基而不是在二ter中的N2位置，将7H-吡啶并[4,3-c]咔唑环二聚化，从而导致DNA双嵌入二聚体实际上没有抗肿瘤特性。但是，在N2原子进行季铵化后，由N7原子连接的二聚体表现出非常高的DNA亲和力（大于10（9）M-1）并恢复了抗肿瘤活性，从而支持了对正电荷产生抗肿瘤活性的需求。这些二聚体。在氨基甲基或羧基的7H-吡啶并咔唑环的C6上进行介绍，为了增加分子的亲水性或使它们能够使用氨基酸转运系统，还进行了糖残基或C或N游离氨基酸如Lys或Glu。尽管这些化合物中的一些具有活性，但它们均未显示出二di的药理效力。