... Among the synthetic derivatives, compounds 6c, 6e, and 6f showed the most potent inhibitory activity against the proliferation of ... conditions: (i) ArC⋮CH, PdCl 2 (PPh 3 ) 2 , PPh 3 , CuI, Et 3 N, dioxane, 100 °C sealed tube; (ii) PTSA, EtOH, microwave, 120 °C or 170 °C, 0.5 h. ...