Synthesis and biological activity of 7H-benzo[4,5]indolo[2,3-b]-quinoxaline derivatives

New 7-(2-aminoethyl)-7H-benzo[4,5]indolo[2,3-b]quinoxalines (13–20) were synthesized with high yields starting from 3H-benzo[e]indole-1,2-dione. These compounds were screened for the cytotoxicity, anti-viral activity, interferon inducing ability and DNA affinity compared with the corresponding 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxaline derivatives (1–12). It was shown, that compounds 13–20 bind to DNA stronger (lg Кa = 6.23–6.87) than compounds 1–12 (lg Кa = 5.57–5.89). Anti-viral activity is significantly reduced with annulations of benzene ring in Indoloquinoxaline moiety 13–20.

Graphical abstractSynthesized 7-(2-aminoethyl)-7H-benzo[4,5]indolo[2,3-b]quinoxalines bind to DNA stronger (lg Кa = 6.23–6.87) and exhibit significantly lower anti-viral and interferon inducing activities than 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxalines (lg Кa = 5.57–5.89).Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► We have synthesized new benzo-analogs (BIQ) of indoloquinoxalines (IQ). ► We show higher affinity to DNA of BIQ comparatively to IQ. ► BIQ appeared less active as IFN-inducers an antivirals then IQ. ► Despite higher DNA affinity cytotoxicity of BIQ is similar to the same of IQ.