Synthesis and Biological Activity of Some Novel (Oxazol-5-yl-phenyl)-thiourea Derivatives

Aims: Synthesis and biological evaluation of some [(5-oxazolyl)-phenyl]-thiourea derivatives as potential antiviral agents. Background: (5-Oxazolyl)-phenyl derivatives were derived from the design of mycophenolic acid structurally related analogues. The (5-oxazolyl)-phenyl fragment is an excellent composition for many novel structure compounds having good pharmaceutical properties, such as immunosuppressive, antiviral and anticancer. In the present study, we present combinations of thiourea group and (5-oxazolyl)-phenyl fragment. The antiviral activity, cytotoxicity and IMPDH activity of the title compounds were evaluated in vitro bioassay. Objective: [(5-Oxazolyl)-phenyl]-thiourea derivatives containing different substituted benzene rings were synthesized by introducing thiourea linker. All the synthesized derivatives were screened for their in vitro antiviral evaluation and inosine monophosphate dehydrogenase activity. Method: A series of [(5-oxazolyl)-phenyl]-thiourea derivatives were synthesized by the reaction of thiocarbonyldiimidazole with amines. This was an effective method for introducing the thiourea group in the (5-oxazolyl)-phenyl structure. All of the synthesized derivatives were screened for their in vitro antiviral activity against influenza A virus, coxsackievirus B3, herpes simplex virus type 1 and inosine monophosphate dehydrogenase activity. Result: The results of the screening revealed that compounds 4i, 4j, 4k, 7m, 7n and 7o showed comparable activity towards IMPDH compared the control drug. Compounds 4k, 4l, 7m and 7n exhibited potent activity towards both RNA virus influenza A virus, coxsackievirus B3 and DNA virus HSV-1 at low micromolar concentrations. The activities of most compounds directly linked to the substituted benzene ring by the thiourea group were superior to those of the compounds which had the methylene linkage. Conclusion: The in vitro biological assays indicated that most of target molecules having combinations of thiourea group and (5-oxazolyl)-phenyl fragment exhibited antiviral activity and IMPDH activity compared the control drugs.