Structure-activity relationships of new antiviral compounds.

In preliminary experiments, the compound 2-amino-5-(2-sulfamoylphenyl)-1,3,4-thiadiazole (G413) was shown to possess high activity against DNA viruses (herpes simplex viruses 1 and 2 and adenovirus 17) and RNA viruses (poliovirus 1, echovirus 2, and coxsackievirus B4). Experiments on the replicative cycle of poliovirus 1 and production of infectious RNA viruses demonstrate that this compound probably prevents assembly of virus particles by acting on structural proteins. In the present experiments, results concerning the activity of derivatives of G413 after side-chain modification are reported. Modification of the primary amine H to CH3 or CH2-CH = CH2 produced a loss of activity against DNA viruses, but inhibitory action on RNA viruses was preserved. Modification to CH2CH3 resulted in the loss of antiviral activity.