title: Biting deterrence and insecticidal activity of hydrazide-hydrazones and their corresponding 3-acetyl-2,5-disubstituted-2,3-dihydro-1,3,4-oxadiazoles against Aedes aegypti.
abstract: BACKGROUND
  Taking into account the improvement in insecticidal activity by the inclusion of fluorine in the hydrazone moiety, the authors synthesized new 4-fluorobenzoic acid hydrazides and 3-acetyl-2,5-disubstituted-2,3-dihydro-1,3,4-oxadiazoles, substituting a phenyl group or a heteroaryl ring carrying one or two atoms of F, Cl and Br, and investigated their biting deterrent and larvicidal activities against Aedes aegypti for the first time.
  
  
  RESULTS
  The compound 3-acetyl-5-(4-fluorophenyl)-2-[4-(dimethylamino)phenyl]-2,3-dihydro-1,3,4-oxadiazole (17) produced the highest biting deterrent activity (BDI = 1.025) against Ae. Aegypti, followed by 4-fluorobenzoic acid [(phenyl)methylene] hydrazide (1). These activity results were similar to those of N,N-diethyl-meta-toluamide (DEET), which showed a proportion not biting of 0.8-0.92. When compounds 1 and 17 were tested on cloth worn on human volunteers, compound 1 was not repellent for some volunteers until present in excess of 500 nmol cm(-2) , while compound 17 was not repellent at the highest concentration tested (1685 nmol cm(-2) ). In the larvicidal screening bioassays, only compounds 10, 11, 12 and 17 showed 100% mortality at the highest screening dose of 100 ppm against Ae. aegypti larvae. Compounds 11 and 12 with LD50 values of 24.1 and 30.9 ppm showed significantly higher mortality than 10 (80.3 ppm) and 17 (58.7 ppm) at 24-h post-treatment.
  
  
  CONCLUSIONS
  The insecticidal and biting deterrent activities were correlated with the presence of a halogen atom on the phenyl or heteroaryl substituent of the hydrazone moiety.
authors.affiliation: National Center for Natural Products Research, The University of Mississippi, University, MS 38677, USA. ntabanca@olemiss.edu
authors.forename: Nurhayat
authors.initials: N
authors.lastname: Tabanca
authors.forename: Abbas
authors.initials: A
authors.lastname: Ali
authors.forename: Ulrich R
authors.initials: UR
authors.lastname: Bernier
authors.forename: Ikhlas A
authors.initials: IA
authors.lastname: Khan
authors.forename: Bedia
authors.initials: B
authors.lastname: Kocyigit-Kaymakcioglu
authors.forename: Emine E
authors.initials: EE
authors.lastname: Oruç-Emre
authors.forename: Seda
authors.initials: S
authors.lastname: Unsalan
authors.forename: Sevim
authors.initials: S
authors.lastname: Rollas
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D006801:Humans; D006835:Hydrazones / Q000494:pharmacology*; D007299:Insect Bites and Stings / Q000517:prevention & control; D007302:Insect Repellents / Q000494:pharmacology*; D010069:Oxadiazoles / Q000494:pharmacology*
chemical_list: D006835:Hydrazones; D007302:Insect Repellents; D010069:Oxadiazoles