Design, Synthesis And Anti-HCV Activity Of Novel Benzothiazole Derivatives As NS5A Inhibitors And Some Others Studies

This thesis includes two parts:(1) Design, synthesis and biological evaluation ofnovel benzothiazole anti-Hepatitis C Virus (HCV) compounds using HCV NS5Ainhibitor GL100953as the lead compound;(2) Discovery of a novel synthetic methodthe construction of multi-substituted benzene derivatives. The highly substitutedbenzene derivatives can be synthesized in one-step by treating thiazolidinedione orrhodanine-based spiro-substrates with KOH.1. Design, Synthesis and Anti-HCV activity of NovelBenzothiazole Derivatives as NS5A InhibitorsIn recent years, the incidence of HCV infection is increasing rapidly. It isestimated that HCV infection afflicts approximately170million people worldwide.Moreover, HCV infection is the leading cause of liver cirrhosis and hepatocellularcarcinoma. PEG-IFN/RBV adjunct therapy is the main regimen for the treatment ofHCV infection. However, it has suffered from limited efficacy, narrow spectrum fordifferent genotypes and severe drug resistance. The HCV non-structural protein NS5Ahas been established as a viable target for the development of direct acting antiviraltherapy. The development of NS5A inhibitors as novel anti-HCV agents is a highlyactive research area.In the present study, HCV NS5A inhibitor GL100953was used as the leadcompound and a series of novel benzothiazole NS5A inhibitors were designed,synthesized and assayed. First, scaffold hopping was performed based on thephenylthiazole core of GL100953. The benzothiazole derivative GL110509showedbetter anti-HCV activity than GL100953. Second, structure-activity relationship studyof the amide part of GL110509was performed. Various amide (A01-A13), amine(B01-B02), sulfamide (C01-C03) and di-sulfamide (D01) derivatives were designedand synthesized. In vitro anti-HCV assay revealed that compounds B02, C03and D01showed good inhibitory activity against HCV RNA replica with IC50values of1.46mol·L-1,5.76mol·L-1and2.99mol·L-1, respectively. Second, structuraloptimization of di-sulfamide derivative D01was performed by introducing varioussubstitutions on the phenyl group. The2-fluoro derivative D02showed the bestanti-HCV activity (IC50=486.2nmol·L-1) and selectivity (CC50>50μmol·L-1). Third,substitutions on the proline of compound D02were further optimized. The removal of the carbobenzoxy group has little influence of the activity. The resulting compoundD15(IC50=400nmol·L-1) showed similar activity to D02. The replacement of thecarbobenzoxy group with hydrocinnamoyl group led to improvement of the activity.Compound D19was the most active compound with low cellular toxicity (IC50=190nmol·L-1, CC50>50μmol·L-1, selective index=357), which represents a promisinglead compound for further optimization. Currently, NS5A inhibition assay atmolecular level has not been reported. A new method based on surface plasmonresonance (SPR) was developed to evaluate the interaction between NS5A and itsinhibitor.2. Discovery of an Unprecedented Reaction for the Synthesis ofPenta-substituted Benzene DerivativesMulti-substituted benzene derivatives are widely distributed with diversefunctions. They are always used as important intermediates and organic materials andare privileged structures in therapeutic drugs. Current synthetic methods for theconstruction of multi-substituted benzene derivatives have several limitations such asharsh reaction conditions, the use of transition metal or heavy metal as catalysts, andthe use of environmentally unfriendly solvents (e.g. toluene and acetonitrile).Previously, we reported the synthesis of thiazolidinedione or rhodanine-basedspiro-compounds by asymmetric cascade reaction. Interestingly, thesespiro-compounds can be converted to five-substituted benzene derivatives in one stepusing KOH as the base and EtOH/H2O (1:1) as the solvent. The unprecedentedreaction has several advantages such as good yield (50.26%~73.26%), broad substratescope, low-cost and using environmental friendly solvent. This synthetic method iseconomic and green and the resulting benzene derivatives have three reactive groups(formyl, phenolic hydroxyl and amide groups), which are easy for furthertransformation.In summary, a total of64anti-HCV benzothiazole derivatives were designed andsynthesized and a new method for the synthesis of multi-substituted benzenederivatives was developed. The novelty of this thesis lies in that:(1) Novelbenzothiazole derivatives were designed and synthesized and several of them showednanomolar anti-HCV activity. In particular, compound D19was highly active withlow cellular toxicity, which can be used as a high quality lead compound for thedevelopment of novel anti-HCV agents and provided a novel chemical probe for chemical biology study;(2) A highly efficient and environmental friendly reaction forthe construction of penta-substituted benzenes was discovered.