title: Synthesis and biological activity of pyridazine amides, hydrazones and hydrazides.
abstract: BACKGROUND
  Optimization studies on compounds initially designed to be herbicides led to the discovery of a series of [6-(3-pyridyl)pyridazin-3-yl]amides exhibiting aphicidal properties. Systematic modifications of the amide moiety as well as the pyridine and pyridazine rings were carried out to determine if these changes could improve insecticidal potency.
  
  
  RESULTS
  Structure-activity relationship (SAR) studies showed that changes to the pyridine and pyridazine rings generally resulted in a significant loss of insecticidal potency against green peach aphids [Myzus persicae (Sulzer)] and cotton aphids [(Aphis gossypii (Glover)]. However, replacement of the amide moiety with hydrazines, hydrazones, or hydrazides appeared to be tolerated, with small aliphatic substituents being especially potent.
  
  
  CONCLUSIONS
  A series of aphicidal [6-(3-pyridyl)pyridazin-3-yl]amides were discovered as a result of random screening of compounds that were intially investigated as herbicides. Follow-up studies of the structure-activity relationship of these [6-(3-pyridyl)pyridazin-3-yl]amides showed that biosteric replacement of the amide moiety was widely tolerated suggesting that further opportunities for exploitation may exist for this new area of insecticidal chemistry. Insecticidal efficacy from the original hit, compound 1, to the efficacy of compound 14 produced greater than 10-fold potency improvement against Aphis gossypii and greater than 14-fold potency improvement against Myzus persicae. © 2016 Society of Chemical Industry.
authors.affiliation: Dow AgroSciences, R&D, 9330 Zionsville Road, Indianapolis, IN, USA.
authors.forename: Ann M
authors.initials: AM
authors.lastname: Buysse
authors.affiliation: Dow AgroSciences, R&D, 9330 Zionsville Road, Indianapolis, IN, USA.
authors.forename: Maurice Ch
authors.initials: MC
authors.lastname: Yap
authors.affiliation: Dow AgroSciences, R&D, 9330 Zionsville Road, Indianapolis, IN, USA.
authors.forename: Ricky
authors.initials: R
authors.lastname: Hunter
authors.affiliation: Dow AgroSciences, R&D, 9330 Zionsville Road, Indianapolis, IN, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Babcock
authors.affiliation: Dow AgroSciences, R&D, 9330 Zionsville Road, Indianapolis, IN, USA.
authors.forename: Xinpei
authors.initials: X
authors.lastname: Huang
mesh_terms: D000577:Amides / Q000138:chemical synthesis / Q000494:pharmacology; D000818:Animals; D001042:Aphids / Q000187:drug effects* / Q000254:growth & development; D006835:Hydrazones / Q000138:chemical synthesis / Q000494:pharmacology; D007306:Insecticides / Q000138:chemical synthesis* / Q000494:pharmacology*; D009758:Nymph / Q000187:drug effects; D011724:Pyridazines / Q000138:chemical synthesis / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: D000577:Amides; D006835:Hydrazones; D007306:Insecticides; D011724:Pyridazines
keywords: Aphis gossypii; Myzus persicae; cotton aphid; green peach aphid; hydrazide; hydrazine; hydrazone; insecticide; pyridazine; structure-activity relationship