Symmetric bis-benzimidazoles as DNA minor groove-binding agents with anti-tumour and antibacterial activity, and the evolution of the drug ridinilazole for the treatment of Clostridium difficile infections.

We report the synthesis of a range of symmetrical bis-benzimidazoles (BBZ) which possess anticancer and antibacterial activities. One of these BBZs has specific activity against Clostridium difficile and is currently in a phase 3 clinical evaluation as the drug ridinilazole. X-ray and computer modelling studies showed that BBZs typically exhibit high specificity for oligonucleotide sequences that occur in the minor groove of DNA.