Structure-Activity Relationships in the Series of Eremomycin Carboxamides

Abstract

A series of new carboxamides of the glycopeptide antibiotic eremomycin was synthesized and investigated in vitro. The goal of the study was the comparison of the influence of the substituents introduced onto the eremomycin skeleton on the activity of these compounds against vancomycin susceptible and resistant bacterial strains. Eremomycin amides derived from amines with small substituents (C₀-C₄) demonstrated antibacterial activity against vancomycin susceptible strains similar to that of the parent antibiotic and were inactive against vancomycin resistant strains. The derivatives of alkylamines with linear lipophilic substituents (like C₁₀H₂₁) were active against VanA. and VanB enterococci strains with the scope of activity similar to that of N'-decyl or 7d-CH₂NH-decyl eremomycins described earlier. Eremomycin amides of 5-methoxy- and 5-benzyloxytryptamine were active both against vancomycin susceptible and resistant strains. The introduction of a spacer (lysine or piperazine) between the decyl and antibiotic moieties did not seriously influence antibacterial properties of the compounds in comparison with the corresponding derivatives without a spacer. The most active carboxamides are of interest for secondary modifications of the antibiotic.