Synthesis and virucidal activity of 5-substituted tropolones

Abstract

In 2009, a new type of influenza A virus (H1N1) led to an influenza pandemic. This particular virus subsequently acquired drug resistance, and the development of new virucidal agents is therefore urgently required to overcome the threat of further infection in the future. Hinokitiol and its derivatives have been reported to exhibit a broad range of anti-bacterial and anti-fungal activities. Nine different 5-substituted tropolones have been synthesized in the current study and evaluated in terms of their virucidal activity against five kinds of influenza virus. Only 5-substituted tropolones bearing nitro and iodo groups showed virucidal activity. These results suggested that tropolone derivatives of this type required a low pKa value and hydrophilic properties to show virucidal activity.