Synthesis of new α-amino nitriles with insecticidal action on Aedes aegypti (Diptera: Culicidae)

Aedes aegypti is the principal vector of arboviral pathogens that may cause diseases as dengue fever, chikungunya and zika. The harmful environmental effects of commercial pesticides coalesced with the development of insecticide-resistant populations encourage the discovery and generation of new alternative products as a tool to reduce the incidence of vector-borne diseases. In this work, through the classic three component Strecker reaction of commercial benzaldehydes, cyclic secondary amines and KCN, a new series of nine α-amino nitriles, girgensohnine analogs, has been synthetized and screened for larvicide and adulticide properties against A. aegypti, one of the dominant vectors of dengue, chikungunya and zika in tropical and subtropical areas all over the world. Molecules 3 and 4 were identified as potential larvicidal agents with LC50 values of 50.55 and 69.59 ppm, respectively. Molecule 3 showed 100% of mortality after 2 h of treatment when a concentration of 30 ppm in adulticidal assays was evaluated. Additionally, in order to elucidate the mode of action of these molecules, their acetylcholinesterase (AChE) inhibitory properties were evaluated using the Ellman assay. It was found that the molecules possess a weak AChE inhibitory activity with IC50 values between 148.80 and 259.40 μM, indicating that AChE could not be a principal target for insecticide activity.