名称:
Synthesis and Quantitative Structure−Activity Relationships of New 2,5-Disubstituted-1,3,4-oxadiazoles
摘要:
Fourteen new 2,5-disubstituted-1,3,4-oxadiazoles, namely (i) six 2- [2,2-dimethyl-3-(2,2-dichlorovinyl)-cyclopropyl] -5-substituted-1,3,4-oxadiazoles and (ii) eight 2-substituted-phenoxymethyl-5-substituted-aryl-1,3,4-oxadiazoles, were synthesized and evaluated for their insect growth regulatory activity against second-instar larvae of armyworm (Pseudaletia separata Walker). Two of these compounds (7 and 8) showed good insecticidal activities, with LC50 values of 14.33 and 15.85 mug/mL, respectively. Steric parameters (e.g., the molecular length d and the ratio of the nonpolar surface area and polar surface area V-1/V-2) and semiempirical quantum parameters (e.g., the molecular total energy E-t and the lowest unoccupied molecular orbital energy E-LUMO and so on) of these compounds, as well as those of six other 2,5-disubstituted-1,3,4-oxadiazoles reported, were acquired by the molecular modeling method and the PM3-SCF-MO method, respectively. With the help of the synthons' activity contribution method based on the Free-Wilson approach in its Fujita-Ban variant, quantitative structure-activity relationships were studied by regressing half-lethal concentrations against the above parameters.