We have discovered several tubulin-active compounds in our previous studies. In the establishment of a compound library of small molecule weight tubulin ligands, 14 new N-3- haloacylaminophenyl-N′-(alkyl/aryl) urea analogs were designed and synthesized. The structure–activity relationship (SAR) analysis revealed that (i) the order of anticancer potency for the 3-haloacylamino chain was following–CH2Br>–CHBrCH3;(ii) the N′- ...