Synthesis And Biological Evaluation Of 2,4-disubstituted Phthalazinones As Aurora Kinase Inhibitors

Aurora kinases,as one of serine/threonine kinase superfamily,play an important role in the process of cell mitosis such as centrosome maturation,mitotic spindle formation,chromosome segregation and cytokinesis during mitosis.The family includes three kinases designated as Aurora A,Aurora B and Aurora C.Aurora kinases have become promising anticancer targets,and many small molecules as Aurora kinases inhibitors were in clinical trials,such as AZD1152,VX-680/MK-0457,AT9283,MLN8054 and AMG900.Phthalazinones exhibit broad activities including antitumor,antifungal,antiallergy and antihypertensive activities.Moreover,it is an important pharmacology core for Aurora kinases.Therefore,in this thesis,we designed,synthesized 17 2,4-disubstituted phthalazinones and evaluated their biological activities including antiproliferation,inhibition against Aurora kinases and effects on cell cycle arrest.First,hydrazine insertion into phthalic anhydride affords phthalazine-1,4-dione in quantitative yield.Then dibromination followed by monohydrolysis gives the desiredintermediatebromophthalazinoneingoodyield.Subsequentthe methylbenzamide side chain displaces the hydrogen atom at the 2-position of bromophthalazinone,and finally the target compounds were obtained via palladium-catalyzedSuzukicouplingreactionorpalladium-catalyzed Buchwald-Hartwig coupling reaction.The antiproliferative activities of target compounds 11a?g,12a?g and 13a?c were screened against five human tumor cell lines?HeLa,A549,HepG2,LoVo and HCT116?by MTT assay,and found compound12c showed potent cytotoxicities with IC₅₀0 values in range of 2.2?4.6?M.Next,compounds 12b,12c,12f,12g and 13a were selected to identify the inhibition activities against Aurora kinases by Kinase-Glo luminescent kinase assay in vitro,and compound 12c showed strong inhibitory effect against AurA and AurB with the IC₅₀values were 118±8.1 and 80±4.2 nM,respectively.Western Blot showed that compound 12c obviously decreased phosphorylation of AurA on Thr288 and AurB on Thr232 in a dose-dependent manner.Docking simulation was performed using the Schrodinger software and the results showed the amide group at C2 of 12c can form hydrogen bond with Asp287 in AurA and form hydrogen bond with Ala173 in AurB.In addition,compound 12c could significantly arrest cells cycle in the G2/M phase by regulating the expression of cyclinB1 and cdc2.In summary,we described a series of 2,4-disubstited phthalazinones small molecule inhibitors that showed potent antitumor activities and strong Aurora kinase inhibitory.These results provide important theoretical basis for the further design and synthesis of 2,4-disubstituted phthalazinones.