Benzothiazepines (zhuo Lv) Class Of Gsk 3¦Â Non-atp Competitive Inhibitors Of The Design, Synthesis And Structure-activity Relationship Studies,

Glycogen Synthase Kinase 3β(GSK 3β) is a multifunctional serine/threonine protein kinase implicated in the regulation of many physiological responses in mammalian cells by phosphorylating a variety of cytoplasmic and nuclear proteins. To date, it is approved to be a key drug target and inhibitors of GSK 3βmight have therapeutic potential for the treatment of diabetes, Alzheimer's disease and cancer. Development of GSK 3βinhibitors is already a hot spot for medicinal chemists in recent years.There are mainly three kinds of small molecular GSK 3βinhibitors to inhibit GSK 3βactivity through three distinct mechanisms:(1) metal ion competitive inhibitors (in Mg2+ binding site), eg. Li+; (2) ATP competitive inhibitors (in ATP binding pocket), eg. maleimides as a representative; and (3) non-ATP competitive inhibitors (in substrate interaction domain), eg. thiadiazolidinones (TDZDs). The non-ATP competitive inhibitors show much higher selectivity than the other two.Non-specific protein kinase inhibition by ATP site-directed inhibitors might have widespread effects. This is the case of the great majority of GSK 3βinhibitors discovered until now. All of them show many others kinases activities diminishing their drug development possibilities. Non-ATP-competitive GSK 3βselective inhibitors comparatively represent an efficient pathway for providing real promising drugs for therapeutic intervention. Actually, one of TDZD analogues, NP 12, is currently undergoing PhaseⅢclinical trials for Alzheimer's disease in the EU, which is the only GSK 3βinhibitor under clinical development.The aim of our project is to find out non-ATP competitive GSK 3βactive leads based on previous virtual screening. Corresponding derivatives are to be designed, synthesized by computer-aided drug design and evaluated by in vitro GSK 3βinhibition activity test and enzyme kinetics test. Inhibitors with better selectivity and activity are to be designed and synthesized to obtain structure-activity relationships (SAR) for further research of new drugs for the treatment of diabetes, Alzheimer's and Huntington's diseases.The thesis describes the discovery of lead compound and the modification of non-ATP competitive GSK 3βinhibitors. A virtual screening was conducted by Autodock program, which docked 50,000 drug-like small molecules of Maybridge library at the non-ATP-binding site of GSK 3β. As a result,2,3-dihydrobenzo[b][1,4] thiazepin-4(5H)-one with variable substituents ranked in the top of those selected candidates, likely to have potent inhibition of GSK 3β. Therefore 6 derivatives of these hits were synthesized. Among which,5-benzyl-2-(furan-2-yl)-2,3-dihydrobenzo-[b][1,4]thiazepin-4(5H)-one(CYbc) showed moderate inhibition of GSK 3βin vitro test (IC50:47.69±2.38μM). By catalytic reaction kinetics test, CYbc was approved to be a non-ATP competitive inhibitor of GSK 3βand taken as a novel lead compound, which is structurally different from other inhibitors of GSK 3βand worthy of further study.Modifications of CYbc were conducted based on bioisosterism and group reversing. Twenty nine compounds, obtained from 3 synthetic routes, were subjected to in vitro test, out of which 12 with inhibition activity equivalent to or better than CYbc. These active derivatives also inhibited GSK 3βin non-ATP competitive way. Compound 5-benzyl-2-phenyl-2,3-dihydrobenzo[b][1,4]-thiazepin-4(5H)-one (HZIIca), in which furyl group in CYbc is substituted by phenyl, and compound 4-benzyl-2-phenyl-3,4-dihydrobenzo[f][1,4]-5(2H)-one(HZkca), reversing the amide group in HZIIca, are as potent as CYbc, which provides two new scaffolds with good space for modification. Forty three targets were synthesized by introducing different groups to the nitrogen atom at 5-position in the key intermediate of 2-phenyl-2,3-dihydrobenzo[b][1,4]-thiazepin-4(5H)-one (Scaffold A) or at 4-position in 2-phenyl-3,4-dihydrobenzo-[f][1,4]-5(2H)-one (Scaffold B), or replacing the phenyl group at 2-position in Scaffold B by other aromatic groups. In vitro test of inhibition of GSK 3βshowed that 7 compounds are as potent as HZkca, while 10 compounds are more potent than HZkca. Preliminary SARs were induced.To explore the possible binding conformation, a molecular docking study of the representative compounds HZkcj, HZkcd, HZkke, HZkpa and HZkna, was performed, and the result showed that the compounds interacted well with the non-ATP-binding site of GSK 3β:the phenyl group interacts with Phe 93 byπ～πstacking, carbonyl group with Arg 96 by hydrogen bond, respectively.In order to get enantiomers of HZkcw, from which the active compound HZkcj could be obtained via diazotization and following replacement reaction, we tied to resolute racemic HZkcw using optical acids, but the efforts were failed.A total amount of 53 intermediates and 78 target compounds were synthesized, out of which 97 were not hited by searching of Scifinder. All of the targets were subjected to an in vitro test system established in our lab for evaluating inhibitory activity of GSK 3(3, among which 29 show activity equivalent to or better than the lead CYbc. Preliminary SARs were resulted, which is useful for further design of non-ATP competitive inhibitors of GSK 3βwith higher activity.