5-Carba-pterocarpens: A new scaffold with anti-HCV activity

Hydroalkoxylation-Initiated Cascade on Sulfone-Tethered Aryl Alkynols Gives Cyclic and Spiro-Heterocyclic β-Ketosulfones

Serendipitous formation of cyclic β-ketosulfones is observed when sulfone-tethered arylalkynols are reacted with base. The reaction involves a base-promoted propargyl sulfone to the allene isomerization/intramolecular hydroalkoxylation/retro-oxa-Michael/6-endo-trig Michael addition cascade. Sulfone-tethered alkynyl acrylates gave stereoselective access to a diverse array of spirocyclic β-ketosulfone benzofuran/isochroman/indolines and sulfone-tethered bridged bicyclo[3.3.1]nonane. These cyclic β-ketosulfones could be readily elaborated into benzofuran-fused cyclic sulfones and tetracyclic spiroindoline.

Research progress in pharmacological activities and structure-activity relationships of tetralone scaffolds as pharmacophore and fluorescent skeleton

The tetralone and tetralone derivatives, as crucial structural scaffolds of potential novel drugs targeted at multiple biological end-points, are normally found in several natural compounds and also, it can be used as parental scaffold and/or intermediate for the synthesis of a series of pharmacologically active compounds with a broad-spectrum of bioactivities including antibacterial, antitumor, CNS effect and so on. Meanwhile, SAR information of its analogues has drawn attentions among medicinal chemists, which could contribute to the further research related to tetralone derivatives aimed at multiple targets. This review encompasses pharmacological activities, SAR analysis and docking study of tetralone and its derivatives, expecting to provide a general retrospect and prospect on tetralone derivatives.

Syntheses of pterocarpenes and coumestans via regioselective cyclodehydration

A highly efficient synthetic route to pterocarpenes and coumestans is described. BCl3-mediated dehydrative cyclization of 1,3-diaryloxyacetones under mild conditions permitted regioselective ring closure to afford 3-((2-iodoaryloxy)methyl)benzofurans which were converted to the corresponding pterocarpenes by Pd-catalyzed intramolecular direct arylation. The subsequent benzylic oxidation led to coumestans. This sequence was applied to the formal syntheses of coumestrol and the proposed structure of plicadin as well as total syntheses of flemichapparins B and C.

Promising Anti-Hepatitis C Virus Compounds from Natural Resources

Hepatitis C virus (HCV) infection is a major worldwide problem, which involves approximately 170 million people. High morbidity of patients is caused by chronic infection, which leads to liver cirrhosis, hepatocellular carcinoma and other HCV-related diseases. The sustained virological response (SVR) has been markedly improved to be >90% by the current standard interferon (IFN)-free treatment regimens with a combination of direct-acting antiviral agents (DAAs) targeting the viral NS3 protease, NS5A multi-function protein and NS5B RNA-dependent RNA polymerase, compared with 50–70% of SVR rates achieved by the previous standard IFN-based treatment regimens with or without an NS3 protease inhibitor. However, the emergence of DAA-resistant HCV strains and the limited access to the DAAs due to their high cost could be major concerns. Also, the long-term prognosis of patients treated with DAAs, such as the possible development of hepatocellular carcinoma, still needs to be further evaluated. Natural resources are considered to be good candidates to develop anti-HCV agents. Here, we summarize anti-HCV compounds obtained from natural resources, including medicinal plant extracts, their isolated compounds and some of their derivatives that possess high antiviral potency against HCV.