Structure-Activi ty Studies onPhosphonoacetate

relationships inthehopeofdesigning a superior analog. Results showed that theantiherpesvirus activity hadhighly specific structural requirements. Neither thecarboxylic northephosphono groups could bereplaced. Thedistance between these twogroups is important. Increase ofthis distance caused complete loss ofactivity. However, ifthis distance wasmaintained, theaddition ofgroups tothemethylene carbon resulted inareduction, butnotloss, ofactivity. Ontheother hand, decrease ofthecarbon chain toformic acid didnotdeteriorate its antiherpes activity. Allanalogs tested hadloweractivity thantheparent compound. However, somecompounds withdecreased activity invitro appeared tohavefavorable pharmacological properties invivo.