Synthesis, Characterization and Biological Activity of Alkyl 3-(N-Butylacetamido)propanoates Against Ixodid Ticks

Chemicals are widely used to protect humans from biological threats. Ticks are among the most dangerous biological species, as they transmit dangerous diseases such as Q-fever, Crimean–Congo hemorrhagic fever, tick-borne encephalitis, and others. It is not feasible nor viable to eradicate all tick populations in areas where people spend their leisure time or work. Personal protective equipment in general, and repellents in particular, have therefore become an important means of protection against this biological threat. Previous studies have shown that despite the repellent activity of substances currently used for this purpose, their effective concentrations against the taiga tick are not fit for practical application. In this study, we synthesized a homologous series of alkyl 3-(N-butylacetamido)propanoates with alkyl groups ranging from C1 to C12 and characterized these compounds using nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, and mass spectrometry. We also investigated the biological activity of all the synthesized compounds against the Ixodes persulcatus ticks. We demonstrated that the methyl, propyl and butyl esters of 3-(N-butylacetamido)propanoate exhibit the highest biological activity with an activity level approximately six times higher than that of the commercially available repellent IR3535®.