Study On Synthesis Of Chromanone-fused Oxindoles Derivatives And Their Cytotoxicity Evaluation On Human Leukemia Cells

Anti-cancer is a global issue.Currently,anticancer therapeutic drugs generally have a large toxic side effect and some tumor cells are also become resistant to drugs and need to be used in combination.Therefore,it is imperative to look for new anti-tumor drugs with low toxicity and side effects.While many compounds with natural product skeletons have good anti-tumor activity and oxindole compounds are the focus of researsh.For example,Indirubin and its derivatives have a certain inhibitory effect on tumor cells and Pfizer's SU11248 can be used to treat gastrointestinal stromal tumors and metastatic renal cell carcinoma.In addition,compounds with chromone skeletons are also the focus of research.Furoaloesone is a natural product extracted from Cape Aloe,which has a good inhibitory effect on Ehrlich ascites tumor cell line.Therefore,the modification of skeleton structure of natural products is an important way to find some compounds with certain bioactivity.In this paper,we designed a series of 3,3'-pyrrolidinyl-dispirooxindoles with the active motif chromone by the principle of pharmacophore skeleton migrationvia1,3-dipolarcycloaddition reaction and a series of 3-hydroxymethyl oxindole compounds with chromone skeleton are synthesized by 1,3-H shift/Aldol tandem reaction.Subsequently,we evaluated the in vitro antitumor activity of the synthesized compounds.We expect to find some efficient and low toxic precursor skeletons,which provide a material basis for the evaluation of antitumor activity in vivo.The first part is the synthesis of 3,3'-pyrrolidinyl-dispirooxindoles with chromone via the Knoevenagel reaction and 1,3-dipolarcycloaddition reaction,products bearing four or three consecutive stereocenters consist of two oxindole moieties anda pyrrolidinyl core,includingvicinal spiroquaternarystereocenters fused in one ring structure were smoothly obtained in high yields?up to 89%yield?with good diastereoselectivity?up to>20:1?.Through the study of the applicability of the reaction,it is clearly indicate that N-Me,N-Et,N-Bn and N-Ph protected isatins showed very high reactivity under the optimized reaction conditions,delivering the desired products in good yields and diastereoselectivities?3aa,3ab,3ac,3ad?.Furthermore,it is also found that,regardless of electron-donating substituents?3ak?or electron-withdrawingsubstituents?3aj?on the aromatic ring of isatin derivatives,the corresponding products could also be successfully obtained in good yields with good diastereoselectivities.Furthermore,the reaction could also be conducted using isatylidenyl-chromanones with different substitution patterns without affecting the high reactivity and diastereoselectivities.To extend our strategy further,the sarcosine was also used as substrate to probe the reactivity of differentisatylidenyl-chromanonesandisatin derivatives under the optimal conditions?3''aa-3''fa?.It is found that,regardless of electron-donating substituents orelectron-withdrawingsubstituents on the aromatic ring of isatin derivatives,the corresponding products could also be successfully obtained in good yields with good diastereoselectivities.In the second part,a series of3-?hydroxymethyl?-3-?4-oxo-4H-chromen-3-yl?-2-one compounds were synthesis from four steps by using chromanone and isatin as substrate.We obtained the target products in high yields through the reaction,which was carried out with formalin solution as a raw material and solvent under heating and no catalyst addition conditions via 1,3H-shift/Aldol tandem reaction.Furthermore this route is environmentally friendly,economical,efficient and also provides a method for the construction of 3-hydroxymethyl indole compounds with chromone skeleton.The third part of this work is to evaluate the in vitro antitumor activity of the synthesized compounds.And we used anticancer drug Cisplatin,which is widely used in clinic and has broad-spectrum anticancer activity,as a positive control to study on the antitumor activity of synthetic compounds in vitro and investigated the inhibitory effect of human chronic myeloid leukemia cells?K562?via MTT assay.The results show that the compounds?3ae,3ai,3al,3ba,3bb,3bf,3bi,3bl,3bm,3''ai?have better antitumor activity against K562,and all the value of IC₅₀ are reached the same order of magnitude of positive control Cisplatin?IC50=18.6?M?,showing potential research value.Then the cytotoxicity of these ten compounds on human normal cell line?L929?was studied.The results show that these compounds have low inhibitory activity on human normal cells and the cytotoxicity is lower than positive control of Cisplatin.In order to further study the effect of the structure-activity relationship on the activity of these compounds,we keep the substituents unchanged of four compounds 3ai?12.3?M?,3al?7.8?M?,3ba?12.5?M?,3bb?13.5?M?that have good inhibitory activity on K562 tumor cells and replace the chromone skeleton with the ester group.The results show that the inhibition of K562 tumor cells decreased,and the value of IC₅₀ was all greater than 100,indicating that the chromone structure was the key active skeleton.