Design,Synthesis And Antitumor Activity Of Novel Quinazoline Derivatives As Tyrosine Kinase Inhibitors

Tyrosine kinases(TKs),one of the most members of epidermal growth factor receptors(EGFRs),play an important role in signaling cascade.It regulates cell proliferation,differentiation and migration in many tissue types.The abnormal activation and over-expression of TKs can result in indefinite proliferation of cells and cycle disorders which lead to the initiation,progression,and invasiveness of human cancers.Clinical trials indicated that over-expression of EGFR was observed in many human solid tumors including nonsmall cell lung cancer(NSCLC),glioma,breast,ovarian,head and neck,cervical,prostate,liver,colorectal,gastric,renal cancer,and so on.In clinical application,some drugs were discovered based on this family.Medical researches revealed that EGFR tyrosine kinase was an attractive target of anticancer agents.The inhibition of tyrosine kinase activity could specifically treat cancer,reduce the damage to normal tissues,and thus reduce the side effects of drugs.The target drug development has become a research hotspot of international anticancer drugs.It was discovered that 4-anilinoquinazoline compound was one of the most researched small molecule TK inhibitors because of its multiple advantages in inhibition process of EGFR-TKs including high activity and selectivity,low toxicity and side effects.In order to find potent anticancer drugs,we designed and synthesized a series of novel quinazoine derivatives on the basis of this background.Biological activities of the compounds were also evaluated.The main works we did were shown as the following:1.Based on the interaction between EGFR-TK inhibitor and receptor protein,we designed a series of novel 4-aminostilbene quinazoline derivatives combined with quantitative structure-activity relationship(Q-SAR)and computer-aided drug design(CADD).Stilbene skeleton was introduced into the novel quinazoline derivatives at the 4-position for the improvement of hydrophily.The activity of designed compounds was evaluated with Docking.It was discovered that these derivatives could reach at the ATP binding sites of TK and interact with receptor protein.2.We optimized the synthetic processes of the designed quinazoline derivatives.Firstly,3,4-dimethoxybenzoic acid was selected as starting material.The selective demethylation of the synthetic 6,7-dimethoxyquinazolin-4(3H)-one controlled the site of the introduction of side chains.However,from the experimental results we knew that the selectivity of demethylation was poor which would give mixed products.Secondly,substituted arylaldehydes were selected as starting materials.Then the target compounds were synthesized from starting materials by cyanation,etherification,nitration,reduction,cyclization,chlorination and amination.In this process,the reduction and cyclization,chlorination and amination were combined together,respectively,which simplified the reaction steps.While there were still some disadvantages in the route.We found that the chlorination of the quinazolin-4(3H)-one showed regioselectivity which resulted in the production of by-products.Thus the yield of production was lowered and the reaction system was hard treated.On the other hand,thionyl chloride with high pollution was used which was dangerous to the environment.In order to overcome the disadvantages,we improved the former route by treating 2-aminobenzonitrile with DMF-DMA directly.And then aromatic amines were added.The target products were obtained by formamidine,cyclization,and Dimroth rearrangement reaction.The strategy had several advantages,such as mild conditions,high selectivity,simple treatments,environmentally benign,high yields,and so on,which made this method more suitable for the syntheses of quinazoline compounds.44 kind novel of quinazoline derivatives and their hydrochloride were synthesized through the optimized routes.All the synthesized compounds were characterized by IR,1H NMR,13C NMR and HRMS or elemental analysis.3.In order to overcome the drawbacks of long reaction time,low yields and poor stereoselectivity,we investigated the synthetic method for preparing stilbene skeleton.Reaction efficiency was significantly improved under microwave irradiation.14(E)-stilbene derivatives were obtained under microwave-assisted solvent-free condition.Compared with conventional heating method,this strategy exhibited significant advantages,such as higher stereoselectivity,shorter reaction time,more environmental friendly,and so on.4.4-aminostilbene moiety was one of the most important fragments in the designed quinazoline derivatives.It was obtained from the reduction of 4-nitrostilbene.However,part of double bond was reduced during the reaction.In order to overcome the problem of poor selectivity during the reduction of nitro group in 4-nitrostilbene,we investigated the selective reduction of C=C bond and nitro group.C=C bonds of 13 4-nitrostilbene were chemoselectively reduced in the presence of metal containing mesoporous carbon material as effective catalyst.On the other hand,the highly selective reduction of nitro group of 4-nitrostilbenes was also facile to be achieved in the presence of FeC13 and active carbon under N2 atmosphere.The 15 obtained compounds were used as important intermediates for the preparation of 4-aminostilbenequinazoline derivatives.This work provided a novel method for selective reduction of other kinds of unsaturated bonds.5.The synthetic methods of N,N-dimethyl-N'-arylformamidines as important intermediates of quinazoline derivatives were also investigated.During the process,the replacement of DMF-DMA by the imine salt obtained from DMF and dimethyl sulfate showed excellent efficiency.Experimental results showed that the reaction was affected by the type and position of substituent groups.Arylamines bearing cyano group or nitro group at C-2 were hard to react with imine salt until in the presence of bases.And the reaction could easily act when the electron donating groups(EDG)attached on the arylamine in the presence of bases.6.The synthesized compounds were evaluated on multiple human tumor cells.The results indicated that the novel quinazoline derivatives exhibited excellent activity with an IC50 of 1?5 ?M in cell level.All the compounds were extremely effective in inhibiting the growth of these cell lines than Gefitinib.At the same time,several potent compounds with effective activity were selected as representative model of the same series into binding site of EGFR to investigate the molecular docking,generate and assess a pharmacophore model(hypothesis).The docking and pharmacophore model provided scientific basis for further research of tyrosine kinase inhibitors.