Antitumor agent-138 (compound 5b) is an inhibitor against tubulin polymerization at tubulin colchicine-binding sites, with IC 50 of 1.87 μM. Antitumor agent-138 arrests the cell cycle at G2/M phase and induces an apoptosis in MCF-7 cells. Antitumor agent-138 inhibits cells migration and angiogenesis.