Synthesis and biological evaluation of novel β-carboline derivatives as Tat–TAR interaction inhibitors

Four new β-carboline derivatives were synthesized bearing guanidinium group or amino group-terminated side chain targeting the TAR element. Compounds 5 and 6 with terminal guanidinium group showed inhibitory activities on Tat–TAR interaction as well as to HIV-1 in MT4 cells. Furthermore, capillary electrophoresis assay implied that compound 6 could not only bind to TAR but also hinder the Tat–TAR interaction.