The new guanidinylation reagent N,N'-diBoc-N " -triflylguanidine was used to efficiently convert multiamine-containing glycosides including kanamycin A and B, tobramycin, paromomycin, and neomycin B to the corresponding fully guanidinylated analogues (guanidinoglycosides). This transformation occurs in the presence of H2O under mild conditions. Guanidinotobramycin and guanidinoneomycin B were found to, inhibit the replication of the HIV virus with activities approximately 100 times greater than the parent aminoglycosides.