Design,Synthesis And Preliminary Biologica Evaluation Of 2-Benzylidenebenzofuran-3(2H)-One And 3-Phenylguinolin-4(1H)-one

DRAK2(DAPK-related apoptosis-inducing protein kinase-2),is one of the five members of DAPK(Death-associated protein kinase)family.As a recently discovered protein kinase,although the physiological mechanism and the signal transduction pathways regulated by DRAK2 have not been expounded completely,the literature have shown that DRAK2 not only associated to the apoptosis and growth of tumor cells and T cell differentiation,but also contributed to the survival of the islet cells.When the expression of DRA K2 was inhibited,the islet cells can significantly resist apoptosis induced by inflammatory factors,hyperlipidemia and hyperglycemia.However,only few DRAK2 small-molecule inhibitors have been reported until now.(Z)-2-(3,4-dihydroxybenzylidene)benzofuran-3(2H)-one(LGP00609),which belongs to a skeleton of aurone,was selected as a hit compound via high-throughput screening of a compound library consisted of 56000 small-molecular compounds by Prof.Jia Li in The National Center for Drug Screening.The IC50 value for DRAK2 was 3.15 ?M at the molecular level.On the basis of LGP00609,structural modification and study of structure-activity relationship were carried out in this dissertation,which mainly consisted of two parts:Part One:Design,synthesis of 2-benzylidenebenzofuran-3(2H)-ones and investigaton of their inhibitory activities against DRAK21.On the bzisis of the structural analysis of LGP00609 and the establishment of the synthetic method,seventy-four 2-benzylidenebenzofuran-3(2H)-one derivatives(in which thirty-six were new compounds)were designed,synthesized and all the structures were characterized by 1N MR,13C NMR and HRMS spectra.2.The inhibitory activities against DRAK2 of all compounds were tested and the preliminary structure-activity relationship was summarized as follows:1)The co-exist of C4-hydrogen-bond donor(-OH)and C3-hydrogen-bond donor(-OH)or the shorter chain length hydrogen-bond acceptor(-OMe,-OEt)in Phenyl A area was favorable to the inhibitory activities against DRAK2;the introduction of electron-withdrawing groups(such as F,Br,CF3)at phenyl A area were adverse for the activities;the 3-ethoxy-4-hydroxy or 3,4-dihydroxy substitution in Phenyl A area was confirmed as the preponderant structure.2)The electronic effect and steric effect of the substituent at phenyl B area influenced the DRAK2 inhibitory activities:introduction of electron-donating groups contributed to the activities,especially introduction of Cs-methoxyl group at phenyl B area;with the decrease of steric effect of the substituents,the inhibitory activities of compounds increased in sequence;except for C5-F substituted compounds,the introduction of electron-withdrawing groups at C5-and C6-position were unfavorable for the activities.Two compounds with better inhibitory activities were obtained:(2)-2-(3-ethoxy-4-hydroxybenzylidene)-5-methoxybenzofuran-3(2H)-one(?-2,IC50=0.33 ?M)and(Z)-2-(3,4-dihydroxybenzylidene)-5-methoxybenzofuran-3(2H)-one(IV-6,IC50=0.25 p.M),which displayed a 10-fold more inhibitory activities than the hit compound.3)Through the structural modification of Ketene C area,the existence of the conjugate system was benefit to the inhibitory activities against DRAK2;compared with pyrrole ring,cyclopentadiene and hexa-heterocycle,the existence of furan ring at Ketene C area was the optimal skeleton.In addition,the planar skeleton was also identified to be favorable for the inhibitory activity.3.The inhibitory activities of some compounds for the DAPK family members and some other 22 protein kinases in house were tested.Some compounds displayed selectivity.The selectivity of ?-6 for the DAPK family members were more than 20-fold;although the selectivity of ?-2 for DRAK1 was only 4-fold,it displayed higher selectivity for the other three protein kinases(more than.60-fold).Generally speaking,?-2 and ?-6 showed higher inhibitory selectivity for DRAK2.4.GSIS assay sho-wed that ?-6 and ?-2 can protect islet cells from palmitate impairment in a dose-dependent manner through reducing cell apoptosis.The palmitate induced GSIS capacity of primary islets could be reversed partly by?-2 and ?-6.The above research achievement provided basis for the potential application of DRAK2 small-molecule inhibitors to treatment of type ? and type ? diabetes.Part Two:Efficient synthetic strategies and preliminary biological evaluation of 3-phenylquinolin-4(1H)-ones.While modified the Ketene C area of LGP00609,an aza-derivative was designed,however,the synthesis was failed when carried out the reactions according to the reported methods.In order to construct 3-phenylquinolin-4(1H)-ones efficiently and further investigate their biological activities,a novel strategy to construct 3-phenylquinolin-4(1H)-one was developed in the Part Two.Meanwhile,the preliminary biological evaluation of this skeleton was also tested.2'-Nitrochalcone epoxide,as the starting material,was catalyzed by 0.05 eq BF3·Et2O to give Meinwald rearrangement product conveniently(isolated yield 96%)which then took place intramolecular reductive-cyclization in the presence of Fe/AcOH to afford 3-phenylquinolin-4(1H)-one(isolated yield 98%).On the basis of optimal reaction conditions for the individual reactions,we attempted to develop a one-pot method to transform 2'-nitrochalcone epoxides to 3-phenylquinolin-4(1H)-ones without isolating the intermediate.As expected,the reaction proceeded successfully and the final products were obtained in high yield(more than 90%).The synthesis method not only avoided the use of poisonous reagent in the reported methods and improved the reaction yields,but also had excellent functional groups compatibility.The method provided the synthetic support for 3-phenylquinolin-4(1H)-ones in potential application to the area of drug discovery.Preliminary biological evaluation of the 3-phenylquinolin-4(1H)-ones,synthesized by this new method,showed that this kind of compounds behaved poor inhibitory activities against DRAK2;in contrast,some compounds displayed inhibitory activities for Protein Tyrosine Phosphatase 1B(PTP1B,another potential drug target for diabetes);in addition,C4-Cl substituted compound VI-6 showed antiproliferative activity for prostate cancer cell lines PC3.The expansion of this skeleton compound library and the phenotypic screening are ongoing.