A new class of guanidino prodrug is efficiently synthesized from an am
ine and an appropriate '-bis(acyloxymethoxycarbonyl)-S-methylisothiour
ea. The N'-bis(acyloxymethoxycarbonyl)-S-methylisothiourea is readily
prepared from S-methylisothiourea and the corresponding acyloxymethyl
carbonochloridate in good yield. The N,N'-bis(acyloxymethyl carbamate)
derivatives of the highly basic guanidino group serve as lipophilic,
uncharged, esterase-activatable prodrugs of simple guanidine containin
g molecules.