Studies On Synthesis And Pharmacological Activity Of Aryloxy Pyridines/Pyrimidines As VEGFR-2 Inhibitors

Malignant tumors has been the major disease of threating human health and life.With the development of molecular biology and cell biology,targeted therapy is becoming the main treatment method for tumors.VEGFR-2,as a member of receptor tyrosine kinase family,is the principal regulator of tumor metastasis and angiogenesis,and the study on anti-tumor drugs targeting VEGFR-2 has attracted more considerable attentions.At present,many VEGFR-2 inhibitors have been approved for the treatment of cancer.Nevertheless,clinical research demonstrates that some inhibitors are connected with the drawbacks of lower efficacy and higher toxicity.In this dissertation,based on the known VEGFR-2 inhibitors as lead compounds,a series of aryloxy pyridines/pyrimidines compounds was designed and synthesized in an attempt to discover VEGFR-2 inhibitors with higher activity and selectivity.Virtual activity screening of target compounds was conducted by using the method of computer-aided drug design,and in vitro inhibitory activity was evaluated against tumor cells.The results will provide theoretical and experimental basis for the development of VEGFR-2 inhibitors.（1）Study on structure design and virtual activity screening of aryloxy pyridines/pyrimidines.Based on the design concept of“Hybrid”,aryloxy pyridines（A）with pyridine as skeleton structure was designed by choosing Sorafenib and Axitinib as lead compounds,and aryloxy pyrimidines（B,C and D）with pyrimidine as skeleton structure were designed by choosing Pazopanib and compound A as lead compounds.On the platform of AutoDock 4.2,molecular docking study was performed between target compounds and VEGFR-2.Virtual activity of target compounds was evaluated according to free energy of binding（△G）,inhibition constant（Ki）and binding mode.The docking results indicated the binding site and binding mode of series A compounds were similar to those of Sorafenib,which exhibited effective virtual activity.The binding site and binding mode of series B,C and D compounds were similar to those of Pazopanib,and some compounds exhibited better virtual activity than that of Pazopanib.（2）Study on synthesis of aryloxy pyridines/pyrimidines.The synthetic routes of series A,B,C and D compounds were determined by retrosynthetic analysis of target compounds.Target compounds were split into two fragments of pyridines/pyrimidines as core and styrylpyridines as side chain.In order to reduce reaction time and improve the yield,microwave irradiation was adopted in the synthesis of styrylpyridines.Series A compounds were synthesized using 2-picolinic acid as starting material,and 22 target compounds were obtained by the reactions of halogenation,ammonolysis and nucleophilic substitution.Series B,C and D compounds were synthesized using 2,4-dichloropyrimidine or 4,6-dichloropyrimidine as starting materials,and 69 target compounds were obtained by nucleophilic substitution and coupled reaction.All target compounds were characterized by ¹H NMR,¹³C NMR and HRMS.Structure analyses of representative compounds were conducted in detail,and their structures were validated by X-ray crystal diffraction.（3）Study on pharmacological activity of aryloxy pyridines/pyrimidines.In vitro inhibitory activity of series A,B,C and D compounds was evaluated against A549 and HepG2 cell lines by CCK-8 assay using Sorafenib,Axitinib and Pazopanib as controls.The results showed that in vitro inhibitory activity of target compounds was basically consistent with virtual activity and most compounds had excellent inhibitory activity against tumor cells.Series A compounds exhibited effective inhibitory activity against A549 and HepG2 cell lines.Among them,A10 showed better inhibitory activity against both cell lines with IC₅₀=12.5 and 20.6μM,and A12 showed better inhibitory activity against both cell lines with IC₅₀=13.2 and 18.2μM,in comparison with Sorafenib(IC₅₀=19.3 and 29.0μM)and Axitinib(IC₅₀=22.4 and 38.7μM).Series B,C and D also exhibited considerable inhibitory activity against A549 and HepG2 cell lines,and some compounds showed better inhibitory activity than that of Pazopanib(IC₅₀=21.2 and36.7μM).When the 2-position of pyrimidine was meta-substituted anilino,series B compounds had better inhibitory activity against A549 and HepG2 cell lines.B4showed potent inhibitory activity against both cell lines with IC₅₀=9.2 and 14.6μM,and B11 showed potent inhibitory activity against both cell lines with IC₅₀=12.7 and22.7μM.When the 4-position of pyrimidine was aryl,series C compounds exhibited better inhibitory activity against A549 and HepG2 cell lines.C24 showed potent inhibitory activity against both cell lines with IC₅₀=9.9 and 18.2μM,and C25 showed potent inhibitory activity against both cell lines with IC₅₀=15.8 and 22.0μM.When the4-position of pyrimidine was meta-substituted anilino,series D compounds displayed better inhibitory activity against A549 and HepG2 cell lines.D4 showed potent inhibitory activity against both cell lines with IC₅₀=16.7 and 21.7μM,and D20 showed potent inhibitory activity against both cell lines with IC₅₀=13.2 and 11.9μM.