title: Synthesis, fungicidal activity, and 3D-QSAR of pyridazinone-substituted 1,3,4-oxadiazoles and 1,3,4-thiadiazoles.
abstract: A series of novel 5-[1-aryl-1,4-dihydro-6-methylpyridazin-4-one-3-yl] -2-arylamino-1,3,4-oxadiazoles, fungicidally active, were synthesized based on bioisosterism and tested in vivo against wheat leaf rust, Puccinia recondita. These compounds were shown to be fungicidally active, and their activity was influenced by the nature of the substituents. By using the three-dimensional quantitative structure-activity relationships (3D-QSAR) method of comparative molecular field analysis (CoMFA), we have studied the structure and activity relationship of the compounds containing both pyridazinone-substituted 1,3,4-thiadiazoles and pyridazinone-substituted 1,3,4-oxadiazoles. The 3D-QSAR modes gave good correlation between the variations on percent inhibition and the steric-electrostatic properties. The results are consistent with a common mode of action for the pyridazinone-substituted 1,3,4-thiadiazoles and the pyridazinone-substituted 1,3,4-oxadiazoles, which further confirms that the 1,3,4-oxadiazole ring is a bioisosteric analogue of the 1,3,4-thiadiazole ring. These offer important structural insights into designing highly active compounds prior to their synthesis.
authors.affiliation: State Key Laboratory for Structural Chemistry Studies of Stable and Unstable Species, Institute of Physical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing, P. R. China, 100871.
authors.forename: Xia-Juan
authors.initials: XJ
authors.lastname: Zou
authors.forename: Lu-Hua
authors.initials: LH
authors.lastname: Lai
authors.forename: Gui-Yu
authors.initials: GY
authors.lastname: Jin
authors.forename: Zu-Xing
authors.initials: ZX
authors.lastname: Zhang
mesh_terms: D005659:Fungicides, Industrial / Q000138:chemical synthesis* / Q000494:pharmacology; D015394:Molecular Structure; D010069:Oxadiazoles / Q000737:chemistry*; D011724:Pyridazines / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013830:Thiadiazoles / Q000737:chemistry*
chemical_list: D005659:Fungicides, Industrial; D010069:Oxadiazoles; D011724:Pyridazines; D013830:Thiadiazoles