The synthesis of 2,3-dihydro-1H-pyrrolo[1,2-a] benzimidazole-5,8-diones (azamitosenes) (I) was carried out in conjunction with the design of potential DNA crosslinkers activated by reduction (reductive alkylation). These quinones resemble mitosene antitumor agents, but are based on the benzimidazole nucleus rather than the indole nucleus. Preliminary results indicate the azamitosenes are potent antitumor agents. Iminoquinone derivatives of azamitosenes (iminoazamitosenes) (II) were synthesized as reductive alkylating agents exhibiting low oxygen toxicity. The iminoazamitosenes are hydrolytically stable in neutral buffers and undergo buffer catalyzed syn/anti isomerization at the imino center. Electrochemical and oxygen reactivity studies in aqueous buffers indicate the change from quinone to iminoquinone is accompanied by an increase in reduction potential and a decrease in oxygen reactivity of the corresponding reduced species.
在合成 2,3-二氢-
1H-吡咯并[1,2-a]苯并咪唑-5,8-二酮(氮杂
咪唑烯)(I)的同时,还设计了通过还原(还原烷基化)激活的潜在 DNA
交联剂。这些
醌类化合物类似于丝
裂霉素类
抗肿瘤药物,但基于
苯并咪唑核而非
吲哚核。初步研究结果表明,偶氮
咪唑烯是一种强效
抗肿瘤药。作为还原性烷基化剂,合成了氮杂
环丁烯的
氨基醌衍
生物(亚
氨基氮杂
环丁烯)(II),具有低氧毒性。亚
氨基偶氮脒烯在中性缓冲液中具有
水解稳定性,并能在缓冲液催化下在亚
氨基中心发生合成/反异构化反应。在
水性缓冲液中进行的电
化学和氧反应性研究表明,从醌到亚
氨基醌的变化伴随着还原电位的增加和相应还原物种氧反应性的降低。