Insecticidal and repellent properties of novel trifluoromethylphenyl amides II

Authors: TSIKOLIA, MAIA - University Of Florida; Bernier, Ulrich; AGRAMONTE, NATASHA - University Of Florida; ESTEP, ALDEN - Navy Entomology Center Of Excellence, Cmave Detachment; Becnel, James; Tabanca, Nurhayat; Linthicum, Kenneth - Ken; GROSS, AARON - University Of Florida; GUERIN, PATRICK - University Of Neuchatel; KROBER, THOMAS - University Of Neuchatel; BLOOMQUIST, JEFFREY - University Of Florida

Submitted to: Pesticide Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2018
Publication Date: 10/1/2018
Citation: Tsikolia, M., Bernier, U.R., Agramonte, N.M., Estep, A., Becnel, J.J., Tabanca, N., Linthicum, K., Gross, A.D., Guerin, P.M., Krober, T., Bloomquist, J.R. 2018. Insecticidal and repellent properties of novel trifluoromethylphenyl amides II. Pesticide Biochemistry and Physiology. 151:40-46. https://doi.org/10.1016/j.pestbp.2018.08.006.
DOI: https://doi.org/10.1016/j.pestbp.2018.08.006

Interpretive Summary: To discover new repellents and insecticides we designed, synthesized and tested novel chemicals for activity against mosquitoes. It is known that the inclusion of single fluorine atoms and trifluoromethyl groups into small molecules can significantly increase their biological activity. Additionally, many amides show mosquito repellent activity, such as N,N-diethyl-meta-toluamide (DEET, today’s gold standard). Here we added which contained 3 fluorine atoms to a number of amide compounds. We found that 2 of these novel compounds repelled Aedes aegypti and Anopheles gambiae mosquitoes better than DEET. These studies suggest that the novel chemicals tested here could further lead to discovery of more compounds with repellent activity.

Technical Abstract: This project focused on the design, synthesis, and testing of trifluoromethylphenyl amides (TFMPAs) as potential mosquitocides and repellents. Fourteen compounds were evaluated for toxicity against larvae and adults of Aedes aegypti. Several compounds were toxic against Aedes aegypti (larval, adult and feeding bioassays) and Drosophila melanogaster (glass-surface contact assay), but were much less toxic than fipronil, with toxicity ratios ranging from 100-fold in the larval assay to 100,000-fold for topical application in adult insects. In repellency bioassays to determine minimum effective dosage (MED), compound N-(2,6-dichloro-4-(trifluoromethyl)phenyl)-2,2,3,3,3-pentafluoropropanamide repelled Ae. aegypti females at lower concentration, 0.017 (+ 0.006) µmol/cm2, better than N, N-diethyl-meta-toluamide (DEET) 0.026 (+ 0.005) µmol/cm2. 2-Chloro-N-(3-(trifluoromethyl)phenyl)acetamide performed better than DEET against two species of mosquitoes: it repelled Ae. aegypti females at 0.013 (+ 0.006) µmol/cm2 and Anopheles gambiae females (in a warm body repellent assay), at a standard exposure of 2 nmol/cm². These studies suggest that the novel chemicals tested here could further lead to discovery of more compounds with repellent activity. These studies revealed novel active structures that could further lead to discovery of more compounds with repellent activity.