Cobalt and iron bis(dicarbollide) conjugates with cholesterol: synthesis and evaluation of antiproliferative activity

Boron-containing conjugates of cholesterol were synthesized by the copper( i )-catalyzed 1,3-dipolar [3+2] cycloaddition reactions of cobalt and iron bis(dicarbollide) azide derivatives with alkynyl cholesterol. The antiproliferative activity (IC 50 ) of the conjugates was evaluated against a series of human cell lines by the MTT assay. All conjugates were shown to be nontoxic (IC 50 >200 µmol L −1 ) and to be applicable for the preparation of boron-containing liposomes as potential drugs for boron-neutron capture therapy (BNCT) of cancer.