ABSTRACT
BACKGROUND: As previously reported, methyl (E)-2-[2-(2-phenylamino-6-trifluoromethylpyrimidin-4-yloxymethyl)phenyl]-3-methoxyacrylate has proven to be a new lead with highly acaricidal activity. Following on from this, in an effort to discover new strobilurin analogues with improved activity, a series of substituted pyrimidines were synthesised and bioassayed. RESULTS: All compounds were characterised by (1) H NMR, IR, MS and elemental analysis. Preliminary bioassays demonstrated that some of the title compounds exhibited notable control of Tetranychus cinnabarinus (Boisd.) at 1.25 mg L(-1) . The relationship between structure and acaricidal activity is discussed. CONCLUSION: Two compounds of particular interest, 6j (SYP-10913) and 6k (SYP-11277), exhibited potent acaricidal activity. The acaricidal potencies of these analogues are higher than that of fluacrypyrim in greenhouse applications, and are comparable with those of commercial acaricides such as spirodiclofen and propargite in field trials.
Subject(s)
Acaricides/toxicity , Mites/drug effects , Pyrimidines/toxicity , Acaricides/chemical synthesis , Acaricides/chemistry , Animals , Drug Discovery , Fabaceae/parasitology , Female , Male , Molecular Structure , Plant Diseases/parasitology , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Structure-Activity RelationshipABSTRACT
BACKGROUND: The intermediate derivatisation method based on bioisosteric replacement led to the discovery of the lead strobilurin compound 5a. To produce new strobilurin analogues with improved activity, a series of substituted pyrimidines were synthesised and bioassayed. RESULTS: The compounds were identified by (1)H NMR, IR, MS and elemental analysis. The highly active compound 5 g was studied by X-ray diffraction. Preliminary bioassays demonstrated that some of the title compounds exhibited excellent acaricidal activity against Tetranychus cinnabarinus (Boisd.) at 10 mg L(-1). The relationship between structure and acaricidal activity is reported. CONCLUSION: The present work demonstrates that strobilurin derivatives containing pyrimidine moieties can be used as possible lead compounds for developing novel acaricides.
Subject(s)
Acaricides/chemistry , Methacrylates/chemistry , Acaricides/chemical synthesis , Animals , Lead/chemistry , Magnetic Resonance Spectroscopy , Mass Spectrometry , Pest Control , Pyrimidines/chemistry , TetranychidaeABSTRACT
A series of novel compounds (5-8) was designed and synthesized by integrating the active pharmacophore of the N-phenylpyrimidin-2-amine fungicide with the structure of strobilurin fungicide. The rationale of this approach was to determine if these new compounds exhibit unique biological activity (selectivity and potency) compared with the commercial standards. The title compounds were prepared from 2-(phenylamino)pyrimidin-4-ols (3) by treatment with one equivalent of intermediates (4) containing strobilurin pharmacophores. 2-(Phenylamino)pyrimidin-4-ols (3) were in turn prepared from phenylguanidines (1) and substituted beta-ketoesters (2). Biological activities evaluated in the greenhouse indicated that compounds 5a, 6a and 7a have good fungicidal activity at 25 mg/L, comparable with that of the commercial standards, cyprodinil and azoxystrobin.
