Design, Synthesis, And Biological Evaluation Of PTP1B Active Site-based2-substituted Ethenesulfonic Acid Ester Derivatives

Protein tyrosine phosphatase1B (PTP1B) has been attracted tremendous attentionand development as potential therapeutic agents in treating Type II diabetes andobesity since it was discovered. Recent two decades, the study of PTP1B inhibitorshas reached great progress; however, because of bad selectivity over PTPs and thelow bioavailability, there were only two compounds entering clinical trials. Andimminent development of potent and PTP1B-specific inhibitor remains necessary.In this thesis, we found an effective PTP1B inhibitor may require a combinationof four moieties: a hydrophilic head, an aromatic center, a linker and a hydrophobictail basing on investigation of recent published papers and further structural analysisof PTP1B inhibitors. In searching for novel PTP1B inhibitors, we prepared a series ofcompounds with a similar functional module arrangement to that of four moieties. Wedesigned sulfonic acid group as the hydrophilic head according to the structuralproperties of PTP1B active site, and the sulfonic acid group can form broad hydrogenbonds with the major amino acid residues. In the template molecule, we designed C-Cdouble bond to link the hydrophilic head and aromatic center. The C-C double bondcan form a Michael acceptor with the sulfonic acid group which can react with thethiol of the CYS215by Michael addition reaction. In order to improve thebioavailability, we changed the sulfonic acid group to sulfonic acid ester or amide bya principle of pro-drug. The aromatic center can form a π-π bond with the residuePHE182of the WPD loop. Also, In the process of reviewing the published papers, wefound the inhibitors can easily react with the residues PHE52and ALA27of thesecondary aryl phosphate binding site by increasing the hydrophobicity; Therefore,we designed sorts of hydrophobic tail and connected the different types ofhydrophobic tail and hydrophilic head with a linker. We proposed that2-substitutedethenesulfonic acid ester derivatives can bind both with the active site and thesecondary aryl phosphate binding site of PTP1B to increase the inhibitory activityagainst PTP1B and enhance the selectivity over TCPTP. In this thesis, we firstly designed and synthesized six series2-substitutedethenesulfonic acid ester derivatives (2-7~2-12). Through screening the inhibitoryactivity of2-7~2-12against PTP1B and selectivity over TCPTP, we found that thesubstituent of the hydrophobic tail has great influence on the inhibitory activity ofPTP1B. What’s more, during the series of2-10, we found the inhibitory activity has atrend of enhanced as the increase length of linker. Unfortunately, most of thecompounds of2-7~2-12showed competitive inhibitory over TCPTP.According to the preliminary SAR, we chose compounds2-10b and2-10c as astructure template for further optimization. We designed series3-1of bis(ethenesul-fonic acid ester) derivatives with five or six atoms length linker referring the structureof difluoromethylene phosphonates PTP1B inhibitors. The inhibitory activity datadisplayed that the compound3-1e with a rigid linker exhibited greater activity andhigher selectivity than that of compound with a flexible linker. We then did somework on the optimization of the hydrophobic tail of2-10b, and the inhibitory activityof3-6showed that the substituent of3-6can enhance the inhibitory against PTP1B,and among of all the compounds,3-6l exhibited the greatest inhibitory activity againstPTP1B with IC50=1.5μM. At the same time, the selectivity over TCPTP showed apositive enhanced as the lipophilic increase of the hydrophobic tail.Further more; we did some optimization on the aromatic center and/orhydrophobic tail of compound2-10c to afford3-9and3-16. After optimization, wefound there has been largely enhanced on the inhibitory activity against PTP1B,especially for the selectivity over TCPTP comparing to3-6. Among all thecompounds,3-9j displayed~20-fold selectivity over TCPTP. What’ more!3-9m,3-16d and3-16f showed potent inhibitory activity against PTP1B with IC50=10.4μM,10.7μM and13.5μM respectively, and to our surprise, these three compounds haveno inhibitory activity against TCPTP. It’s indicated that increasing the length of linkercan enhance the inhibitory activity against PTP1B and selectivity over TCPTP.Moreover, the series of2-substituted ethenesulfonic acid ester derivatives has a lowcytotoxicity on COS-7cell.In addition, we simplified the structure of2-substituted ethenesulfonic acid ester derivatives to2-7at~2-7az and3-18a~3-18c without linker, aromatic center and/orhydrophobic tail. The inhibitory activity data showed2-7at~2-7az and3-18a~3-18chave no activity on the inhibitory of PTP1B and TCPTP, and it’s proved the linker,aromatic center and hydrophobic tail played a necessary role on the inhibitory againstPTP1B and selectivity over TCPTP.In summary, we designed and synthesized1192-substituted ethenesulfonic acidester derivatives with low cytotoxicity basing on the structural properties of PTP1B.The SAR study confirmed the linker length and the hydrophobicity had positiveinfluence on the inhibitory against PTP1B and selectivity over TCPTP. The presentstudy is of considerable important as it provides insights into the design anddevelopment of potent and selective PTP1B inhibitors.