title: Insecticidal, repellent and fungicidal properties of novel trifluoromethylphenyl amides.
abstract: Twenty trifluoromethylphenyl amides were synthesized and evaluated as fungicides and as mosquito toxicants and repellents. Against Aedes aegypti larvae, N-(2,6-dichloro-4-(trifluoromethyl)phenyl)-3,5-dinitrobenzamide (1e) was the most toxic compound (24 h LC50 1940 nM), while against adults N-(2,6-dichloro-4-(trifluoromethyl)phenyl)-2,2,2-trifluoroacetamide (1c) was most active (24 h LD50 19.182 nM, 0.5 μL/insect). However, the 24 h LC50 and LD50 values of fipronil against Ae. aegypti larvae and adults were significantly lower: 13.55 nM and 0.787 × 10(-4) nM, respectively. Compound 1c was also active against Drosophila melanogaster adults with 24 h LC50 values of 5.6 and 4.9 μg/cm(2) for the Oregon-R and 1675 strains, respectively. Fipronil had LC50 values of 0.004 and 0.017 μg/cm(2) against the two strains of D. melanogaster, respectively. In repellency bioassays against female Ae. aegypti, 2,2,2-trifluoro-N-(2-(trifluoromethyl)phenyl)acetamide (4c) had the highest repellent potency with a minimum effective dosage (MED) of 0.039 μmol/cm(2) compared to DEET (MED of 0.091 μmol/cm(2)). Compound N-(2-(trifluoromethyl)phenyl)hexanamide (4a) had an MED of 0.091 μmol/cm(2) which was comparable to DEET. Compound 4c was the most potent fungicide against Phomopsis obscurans. Several trends were discerned between the structural configuration of these molecules and the effect of structural changes on toxicity and repellency. Para- or meta- trifluoromethylphenyl amides with an aromatic ring attached to the carbonyl carbon showed higher toxicity against Ae. aegypti larvae, than ortho- trifluoromethylphenyl amides. Ortho- trifluoromethylphenyl amides with trifluoromethyl or alkyl group attached to the carbonyl carbon produced higher repellent activity against female Ae. aegypti and Anopheles albimanus than meta- or para- trifluoromethylphenyl amides. The presence of 2,6-dichloro- substitution on the phenyl ring of the amide had an influence on larvicidal and repellent activity of para- trifluoromethylphenyl amides.
authors.affiliation: U.S. Department of Agriculture-Agricultural Research Service, Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL 32608, USA. Electronic address: maia.tsikolia@ars.usda.gov.
authors.forename: Maia
authors.initials: M
authors.lastname: Tsikolia
authors.affiliation: U.S. Department of Agriculture-Agricultural Research Service, Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL 32608, USA.
authors.forename: Ulrich R
authors.initials: UR
authors.lastname: Bernier
authors.affiliation: U.S. Department of Agriculture-Agricultural Research Service, Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL 32608, USA.
authors.forename: Monique R
authors.initials: MR
authors.lastname: Coy
authors.affiliation: Navy Entomology Center of Excellence, PO Box 43, Bldg 937, Naval Air Station, Jacksonville, FL 32212-0043, USA.
authors.forename: Katelyn C
authors.initials: KC
authors.lastname: Chalaire
authors.affiliation: U.S. Department of Agriculture-Agricultural Research Service, Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL 32608, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: Becnel
authors.affiliation: U.S. Department of Agriculture-Agricultural Research Service, Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL 32608, USA.
authors.forename: Natasha M
authors.initials: NM
authors.lastname: Agramonte
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677, USA.
authors.forename: Nurhayat
authors.initials: N
authors.lastname: Tabanca
authors.affiliation: U.S. Department of Agriculture-Agricultural Research Service, Natural Products Utilization Research Unit, The University of Mississippi, University, MS 38677, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Wedge
authors.affiliation: U.S. Department of Agriculture-Agricultural Research Service, Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL 32608, USA.
authors.forename: Gary G
authors.initials: GG
authors.lastname: Clark
authors.affiliation: U.S. Department of Agriculture-Agricultural Research Service, Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL 32608, USA.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Linthicum
authors.affiliation: Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, FL 32610-0009, USA.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Swale
authors.affiliation: Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, FL 32610-0009, USA.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Bloomquist
mesh_terms: D000330:Aedes / Q000187:drug effects; D000577:Amides / Q000138:chemical synthesis / Q000633:toxicity*; D000818:Animals; D004330:Drosophila / Q000187:drug effects; D005260:Female; D005658:Fungi / Q000187:drug effects / Q000254:growth & development; D005659:Fungicides, Industrial / Q000138:chemical synthesis / Q000633:toxicity*; D007302:Insect Repellents / Q000138:chemical synthesis / Q000633:toxicity*; D007306:Insecticides / Q000138:chemical synthesis / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50
chemical_list: D000577:Amides; D005659:Fungicides, Industrial; D007302:Insect Repellents; D007306:Insecticides
keywords: Aedes aegypti; Anopheles albimanus; Drosophila melanogaster; Pesticides; Plant pathogenic fungi; Trifluoromethylphenyl amides