D and E Rings May Not Be Indispensable for Antofine: Discovery of Phenanthrene and Alkylamine Chain Containing Antofine Derivatives as Novel Antiviral Agents against Tobacco Mosaic Virus (TMV) Based on Interaction of Antofine and TMV RNA

On the basis of the interaction of antofine and tobacco mosaic virus (TMV) RNA, a series of phenanthrene and alkylamine chain containing antofine derivatives 1–41 were designed, synthesized, and systematically evaluated for their antiviral activity against TMV. The results showed that most of these compounds exhibited good to excellent anti-TMV activity, which indicated that the D and E rings of antofine may not be indispensable. Phenanthrene is important for these compounds, but not the more the better. Phenanthrene, benzene rings, and alkylamine chain containing compounds exhibited good antiviral activity. The optimum compounds, 10, 18, and 19, displayed higher activity than precursor antofine and commercial ribavirin, thus emerging as new lead compounds. The novel concise structure provides another new template for antiviral studies.