ABSTRACT
A series of new 1,2,3-triazole derivatives have been prepared and screened for their antifungal activity against phytopathogenic fungi using the mycelium growth inhibition method in vitro. The results indicated that the 1,2,3-triazole hydrazide scaffold displayed significant antifungal activity. Compound 6ad exhibited the most potent anti-phytopathogenic activity, with EC50 values of 0.18, 0.35, 0.37 and 2.25 µg mL-1 against Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium graminearum, and Magnaporthe oryzae, respectively. In vivo testing demonstrated that 6ad was effective for the control of rice sheath blight, rape sclerotinia rot, fusarium head blight and rice blast caused by the aforementioned phytopathogens. This work suggests that the combination of 1,2,3-triazole and hydrazide moiety could be a promising fungicide scaffold in the future.
Subject(s)
Antifungal Agents/chemical synthesis , Antifungal Agents/pharmacology , Plants/microbiology , Triazoles/chemical synthesis , Triazoles/pharmacology , Antifungal Agents/chemistry , Antifungal Agents/metabolism , Biological Transport , Chemistry Techniques, Synthetic , Plant Diseases/microbiology , Plants/metabolism , Triazoles/chemistry , Triazoles/metabolismABSTRACT
A series of benzimidazole phenylhydrazone derivatives (6a-6ai) were synthesized and characterized by ¹H-NMR, ESI-MS, and elemental analysis. The structure of 6b was further confirmed by single crystal X-ray diffraction as (E)-configuration. All the compounds were screened for antifungal activity against Rhizoctonia solani and Magnaporthe oryzae employing a mycelium growth rate method. Compound 6f exhibited significant inhibitory activity against R. solani and M. oryzae with the EC50 values of 1.20 and 1.85 µg/mL, respectively. In vivo testing demonstrated that 6f could effectively control the development of rice sheath blight (RSB) and rice blast (RB) caused by the above two phytopathogens. This work indicated that the compound 6f with a benzimidazole phenylhydrazone scaffold could be considered as a leading structure for the development of novel fungicides.
Subject(s)
Benzimidazoles/chemical synthesis , Benzimidazoles/pharmacology , Hydrazones/chemical synthesis , Hydrazones/pharmacology , Plant Diseases/prevention & control , Antifungal Agents/chemical synthesis , Antifungal Agents/chemistry , Antifungal Agents/pharmacology , Benzimidazoles/chemistry , Hydrazones/chemistry , Magnaporthe/drug effects , Molecular Structure , Mycelium/drug effects , Oryza/drug effects , Oryza/microbiology , Plant Diseases/microbiology , Rhizoctonia/drug effects , Structure-Activity Relationship , X-Ray DiffractionABSTRACT
A series of 1,2,3-triazole phenylhydrazone derivatives were designed and synthesized as antifungal agents. Their structures were determined based on (1)H-NMR spectroscopy, MS, elemental analysis and X-ray single-crystal diffraction. The antifungal activities were evaluated against four phytopathogenic fungi including Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium graminearum and Phytophthora capsici, by the mycelium growth inhibition method in vitro. Compound 5p exhibited significant anti-phytopathogenic activity, with the EC50 values of 0.18, 2.28, 1.01, and 1.85 µg mL(-1), respectively. In vivo testing demonstrated that 5p was effective in the control of rice sheath blight, rape sclerotinia rot and fusarium head blight. A 3D-QSAR model was built for a systematic SAR profile to explore more potent 1,2,3-triazole phenylhydrazone analogs as novel fungicides.
Subject(s)
Antifungal Agents/chemical synthesis , Antifungal Agents/pharmacology , Hydrazones/chemical synthesis , Hydrazones/pharmacology , Triazoles/chemistry , Antifungal Agents/chemistry , Crystallography, X-Ray , Fungi/drug effects , Hydrazones/chemistry , Mass Spectrometry , Microbial Sensitivity Tests , Models, Molecular , Proton Magnetic Resonance Spectroscopy , Quantitative Structure-Activity RelationshipABSTRACT
The key steps in the synthesis of clavulactone are formation of an enantiopure cyclopentane precursor by epoxide rearrangement and intramolecular carbonyl-ene reaction, construction of the 3,4-dihydro-2H-pyran ring by intermolecular hetero-Diels-Alder reaction, closure of the eleven-membered ring, and finally generation of the lactone functionality by chemoselective allylic C(sp(3))-H oxidation.
Subject(s)
Diterpenes/chemical synthesis , Lactones/chemical synthesis , Catalysis , Molecular Structure , StereoisomerismABSTRACT
The first example of diastereo- and enantioselective aza-MBH-type reaction was accomplished by the asymmetric synthesis of beta-nitro-gamma-enamines via a (1R,2R)-diaminocyclohexane thiourea derivative mediated tandem Michael addition and aza-Henry reaction in good yields (up to 95%) and high enantioselectivities (up to 91% ee) and diastereoselectivities (up to 1:99 dr).
ABSTRACT
A simple and effective method for the synthesis of bioactive imidazo[1,2,4]triazole analogues has been developed utilizing the MCR technique, which involved the reaction of aminotriazoles, isocyanides and aldehydes. The products were characterized by (1)H, (13)C NMR spectroscopy, MS and elemental analysis. Interestingly, compounds 19d, 21a, 21b and 21h displayed good cytotoxic activities at 10(-4) M concentration in the inhibition of tumor cell growth as evaluated by the MTT method.
