Synthesis and antitumor activities of novel 1,4-substituted phthalazine derivatives

A series of 1,4-substituted phthalazine derivatives were designed and synthesized. All the prepared compounds were screened for their cytotoxic activities against A549, HT-29 and MDA-MB-231 cell lines in vitro. Among them, compounds 7a–7h showed excellent selectivity for MDA-MB-231 cell line with IC50 values from 1 nmol/L to 0.92 μmol/L. A preliminary SAR study of these derivatives was performed.