Synthesis and Biological Evaluation of Highly Active 7-Anilino Triazolopyrimidines as Potent Antimicrotubule Agents.

Two different series of fifty-two compounds, based on 3',4',5'-trimethoxyaniline () and variably substituted anilines () at the 7-position of the 2-substituted-[1,2,4]triazolo [1,5-]pyrimidine nucleus, had moderate to potent antiproliferative activity against A549, MDA-MB-231, HeLa, HT-29 and Jurkat cancer cell lines. All derivatives with a common 3-phenylpropylamino moiety at the 2-position of the triazolopyrimidine scaffold and different halogen-substituted anilines at its 7-position, corresponding to 4'-fluoroaniline (), 4'-fluoro-3'-chloroaniline (), 4'-chloroaniline () and 4'-bromoaniline (), displayed the greatest antiproliferative activity with mean ICs of 83, 101, 91 and 83 nM, respectively. These four compounds inhibited tubulin polymerization about 2-fold more potently than combretastatin A-4 (CA-4), and their activities as inhibitors of [H]colchicine binding to tubulin were similar to that of CA-4. These data underlined that the 3',4',5'-trimethoxyanilino moiety at the 7-position of the [1,2,4]triazolo [1,5-]pyrimidine system, which characterized compounds , was not essential for maintaining potent antiproliferative and antitubulin activities. Compounds and had high selectivity against cancer cells, and their interaction with tubulin led to the accumulation of HeLa cells in the G2/M phase of the cell cycle and to apoptotic cell death through the mitochondrial pathway. Finally, compound significantly inhibited HeLa cell growth in zebrafish embryos.