Combretastatin A-4, isolated from the South African bush willow, is known to disrupt vascular function by binding readily to the colchicine site of β-tubulin. Chalcones, with structural features similar to Combretastatin A-4, are also known to inhibit tubulin polymerization by disrupting formation or functionality of its microtubules. Heterocyclic chalcone derivatives have been synthesized in the literature and many act as tubulin binding agents or show significant bioactivity. This research examines the synthesis of indole chalcone and α-halo substituted indole chalcone analogs of Combretastatin A-4 utilizing the Hemetsberger-Knittel indole methodology. The indole aldehyde was combined with a substituted acetophenone under Aldol and Claisen-Schmidt condensation conditions. Although the actual indole chalcone product is unconfirmed through spectroscopic analysis, the Claisen-Schmidt reaction provided the best results. Synthesis of the α-halo indole chalcones utilized the same reaction conditions with an α-halo-3,4,5-trimethoxyacetophenone. To date, the halogenated chalcones have not been isolated. Progress towards their syntheses will offer additional chalcone derivatives of potential biological importance and will be discussed.
