title: Design, synthesis, and quantitative structure-activity relationship study of herbicidal analogues of pyrazolo[5,1-d][1,2,3,5]tetrazin-4(3H)ones.
abstract: A series of pyrazolo[5,1-d][1,2,3,5]tetrazin-4(3H)one derivatives were designed, synthesized, and evaluated for their herbicidal activities where some of these compounds provided >80% control of Brassica campestris at 10 microg/mL. Quantitative structure-activity relationship studies were performed on these compounds using physicochemical parameters (electronic, Verloop, or hydrophobic) as independent parameters and herbicidal activity as a dependent parameter, where herbicidal activity correlated best (r > 0.8) with physicochemical parameters in this set of molecules. The herbicidal activity against B. campestris was mainly affected by the molar refractivity (MR) for R1, Taft (Eso) for R2 or R6, Verloop (Lm) for R3 or R5, and electronic parameters (Hammett's constants) for R4. The optimal MR for herbicidal activity is 0.95. The herbicidal activity against Echinochloa crus-galli was mainly related with the substituents' hydrophobic parameter. The optimal pi parameters for R1 and R4 for herbicidal activity are 0.72 and 0.68, respectively. In general, these compounds showed greater herbicidal activity toward B. campestris than E. crus-galli.
authors.affiliation: State Key Laboratory of Elemento-organic Chemistry, Research Institute of Elemento-organic Chemistry, Nankai University, Tianjin 300071, People's Republic of China.
authors.forename: You-quan
authors.initials: YQ
authors.lastname: Zhu
authors.forename: Chao
authors.initials: C
authors.lastname: Wu
authors.forename: Hua-bin
authors.initials: HB
authors.lastname: Li
authors.forename: Xiao-mao
authors.initials: XM
authors.lastname: Zou
authors.forename: Xue-kai
authors.initials: XK
authors.lastname: Si
authors.forename: Fang-zhong
authors.initials: FZ
authors.lastname: Hu
authors.forename: Hua-zheng
authors.initials: HZ
authors.lastname: Yang
mesh_terms: D001937:Brassica / Q000187:drug effects; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006540:Herbicides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D006574:Heterocyclic Compounds, 2-Ring / Q000138:chemical synthesis* / Q000737:chemistry; D021281:Quantitative Structure-Activity Relationship
chemical_list: D006540:Herbicides; D006574:Heterocyclic Compounds, 2-Ring