A-ring dihalogenation increases the cellular activity of combretastatin-templated tetrazoles.

Abstract:: The combretastatins have been investigated for their antimitotic and antivascular properties, and it is widely postulated that a 3,4,5-trimethoxyaryl A-ring is essential to maintain potent activity. We have synthesized new tetrazole analogues (32-34), demonstrating that 3,5-dihalogenation can consistently increase potency by up to 5-fold when compared to the equivalent trimethoxy compound on human umbilical vein endothelial cells (HUVECs) and a range of cancer cells. Moreover, this increased potency offsets that lost by installing the tetrazole bridge into combretastatin A-4 (1), giving crystalline, soluble compounds that have low nanomolar activity, arrest cells in G2/M phase, and retain microtubule inhibitory activity. Molecular modeling has shown that optimized packing within the binding site resulting in increased Coulombic interaction may be responsible for this improved activity.

Authors:: TM Beale, DM Allwood, A Bender, PJ Bond, JD Brenton, DS Charnock-Jones, SV Ley, RM Myers, JW Shearman, J Temple, J Unger, CA Watts, J Xian

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