Discovery Of Anticoagulation And Amti-tumor Lead Compounds From Click Chemistry And Privileged Sturcture-based Combinatorial Library

During the past two decades,various new synthetic methodologies and concepts have been proposed for the assembly of compound collections.Among them,copper(I)-catalyzed azide-alkyne(3+2)dipolar cycloaddition(CuAAC)click chemistry is generally regarded as one of the most commonly used chemical reactions in chemical biology and medicinal chemistry.And now combination of the CuAAC reaction,miniaturization synthesis with rapid screening has become a highly robust and efficient strategy for discovering bioactive molecules.In this paper,using this methodology,structurally diverse compound libraries were constructed and screened with the aim to develop novel potent inhibitors against thrombosis and malignant tumors.The main content could be divided into the following two parts.Discovery of Novel Factor Xa Inhibitors Based on Click-Chemistry-Based Miniaturization Synthesis and Rapid ScreeningCoagulation Factor Xa was regarded as an attractive target for antithrombotic agents.In the past several years,extensive efforts have been made to develop selective,orally available,small-molecular FXa inhibitors.Four have so far been approved for clinical use,include rivaroxaban,apixaban,edoxaban and betrixaban.Although these novel FXa inhibitors overcome the shortcomings of traditional anticoagulants,they still have some defects,such as the narrow use of drug indications,damage to liver and kidney function,as well as the potential risk of bleeding.Therefore,there is still an urgent need for overcoming the limitations of FXa inhibitors reported so far or discovering new types of potent and specific FXa inhibitors as alternative anticoagulants.In the second chapter of this paper,according to the binding mode with factor Xa,we analyzed the existing potent Factor Xa inhibitors and use target-based privileged fragment design concepts to obtain five alkyne fragments(A1-A4).Then,by reacting these alkyne fragments with diverse azide building blocks using CuAAC reaction,a 52-member triazole library was assembled and an active compound A1N1 was found by rapid screening.Next we take A1N1 as lead compound and modified the indole substituents to obtain five alkyne fragments B1-B5,Then a 54-member 1,2,3-triazole containing combinatorial library are constructed by parallel synthesis.Screening of these triazole derivatives against FXa led to the identification of 6 hit compounds(A1N1,B1N1,B2N1,B4N1,B5N1,B5N4),all of them showed good inhibitory effects(IC50:0.026?4.05 ?M),but did not exceed the positive drug(rivaroxaban IC50:0.05 nM).At the same time,we take the hit compound A1N1 as the lead compound,based on our previous work and the principle of scaffold hopping,designed and synthesized a series of novel indole compounds.Next,these compounds were tested for their inhibitory activities,as a result,all of them showed weak inhibitory effects(IC50:16.45?885.17 M)and none exceeded lead compound A1N1(IC50=4.05?M).Finally,The Sybyl software was used to simulate the binding mode with factor Xa of these compounds,which provided valuable information for further structural optimization.Discovery of Novel CDC25 Protein Phosphatases Inhibitors Based on Click-Chemistry-Based Miniaturization Synthesis and Rapid ScreeningCell Division Cyclin 25(Cdc25)is a kind of dual-specific phosphatases,which can promote the progress of cell division cycle through the dephosphorylation of its substrate:cell cycle dependent kinase(Cdk).At present,CDC25 phosphatase is regarded as a potentially attractive target for anti-tumor drug development.However,there are no drugs aimed at this target for the treatment of cancer currently available on the market.In order to discover effective CDC25 inhibitors and inspired by the preliminary efforts,in the third chapter of this paper,we focused our attention on further optimization of p-benzoquinone and by modified the Linker region obtain a alkyne-bearing privileged fragment M3.Then diverse azide azide-modified peripheral substituents were installed rapidly on this scaffold using CuAAC click chemistry.Finally,a 36-member 1,2,3-trizole-1,4-quinolinedione library was constructed,followed by direct biological screening for the identification of potential 'hits'.The preliminary screening results demonstrated that the compounds M3N6,M3N12,M3N23,M3N21,M3N35 showed excellent inhibitory activity and CDC25 subtype selectivity,which deserves further consideration towards optimizing CDC25 inhibitory activity.In this thesis,fragment-based rapid assembly using the facile CuAAC reaction and rapid screening is used as an efficient tool to identify novel bioactive inhibitors against these targets.As a result,several potential FXa inhibitors and CDC25 phosphatase inhibitors were identified through rapid screening of the constructed combinatorial libraries.Results suggested that some of the tested compounds could be considered as lead compounds and suitable for further optimization.We envisioned that the rapid assembly and in situ screening of focused combinatorial fragment libraries using CuAAC click chemistry will be a highly robust and efficient strategy for establishing SAR and will greatly contribute to the discovery of more bioactive molecules with other therapeutic applications.