Bisbenzimidazole derivatives

Bisbenzimidazole derivatives such as Hoechst 33258 (also known as Pibenz-imol) 28 (Fig. 2) is a A/T base pair selective compound that binds in the minor groove of DNA [37]. To investigate its full potential, a number of benzimidazole Hoechst motifs have been synthesized and evaluated for various biological activities [38-40]. 

Loewe, H. Urbanietz, J. Basic substituted 2,6-bisbenzimidazole derivatives, a novel series of substances with chemotherapeutic activity. Arzneim.-Forsch. 1974, 24, 1927-1933 Chem. Abstr. 1975, 82, 112032. 

Using polymer-immobilized liquid phase synthesis and controlled microwave irradiation, trisubstituted bisbenzimidazoles have been prepared and released with good yield and purity [77]. Furthermore, a wide range of benzimidazole derivatives have been synthesized with excellent yields and purities by simple washing and filtration using liquid phase synthesis on a soluble polymer support [78]. 

Copper(II) catalysed enantioselective decarboxylative aldol-type addition of malonic acid hemithioesters to aldehydes in the presence of tartaric acid-derived bisbenzimidazole and an achiral base was examined. The use of DBU (1) as an achiral base resulted in low enantioselectivity [69]. 

---