Synthesis and Herbicidal Activity of New 2-(1-Carbamoyl-1,2,4-triazol-3-ylsulfonyl)alkanoates
A series of new 2-(1-N,N-dialkylcarbamoyl-1,2,4-triazol-3-ylsulfonyl)alkanoates were synthesized and examined for herbicidal activity against weeds. The herbicidal efficacy varied with the substituents at the alpha-position of the alkoxycarbonyl group and on the nitrogen atom of the carbamoyl moiety. Among the compounds synthesized, 1-N,N-dialkylcarbamoyl-1,2,4-triazole derivatives having a branched alkyl group at the alpha-position of the alkoxycarbonyl group exhibited the most potent herbicidal activity. The chirality of the alpha-position had no effect on the activity. On the basis of biological evaluations, isopropyl 2-(1-N,N-diethylcarbamoyl-1,2,4-triazol-3-ylsulfonyl)-4-methylpentanoate was selected as a promising herbicidal candidate for transplanted rice. Studies on structure-activity relationships using the hydrophobicity parameter log k' revealed that hydrophobicity markedly influenced the herbicidal activity.
Key words: 2-(1-N,N-dialkylcarbamoyl-1,2,4-triazol-3-ylsulfonyl)alkanoates, herbicidal activity, chirality, hydrophobicity.
Differential Accumulation of Protoporphyrin IX between Oxyfluorfen Resistant and Non-Resistant Soybean Cell Lines
The diphenyl ether herbicide oxyfluorfen causes an accumulation of protoporphyrin IX (Proto IX) in plants as a result of the inhibition of protoporphyrinogen oxidase (Protox). We previously reported that an oxyfluorfen-resistant soybean cell line selected by a stepwise selection method grew normally under 10(-7) M oxyfluorfen due to the overproduction of mitochondrial Protox. In the present study, the accumulation and localization of Proto IX in normal and resistant cells after treatment with oxyfluorfen were examined by spectrofluorometry and fluorescence microscopy. The normal cells accumulated great amounts of Proto IX in the presence of 10(-6) and 10(-7) M oxyfluorfen whereas the resistant cells accumulated much less. The level of Proto IX reached a maximum at 4 to 8 hr after treatment under illumination and then gradually decreased. In the dark, the Proto IX content increased linearly until 24 hr and fluorescence from Proto IX was detected in cytoplasm and plasma membrane in the oxyfluorfen-treated normal cells. In resistant cells, chlorophyll autofluorescence was detected in non-treated cells, and Proto IX fluorescence was not detectable. This autofluorescence, however, disappeared with 10(-7) M oxyfluorfen treatment. These results strongly support that the overproduction of mitochondrial Protox is responsible for the resistance to oxyfluorfen in this selected soybean cell line.
Key words: oxyfluorfen, protoporphyrin IX, localization, resistant, soybean cell.
Experimental and Theoretical Studies on Photodegradation of Fungicide Diniconazole
The fungicide diniconazole [(E)-1-(2,4-dichlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol] underwent (E)/(Z) isomerization and subsequent cyclization of its (Z)-isomer to form an isoquinoline derivative on exposure to UV light ([lambda]＞250 nm) in methanol. The molecular geometry of the (Z)-isomer estimated from the semi-empirical AM1 molecular orbital calculations based on measurements of nuclear spin-lattice relaxation times was successfully utilized to simulate the electronic transitions of the fluorescent difluorinated derivative of the (Z)-isomer by CNDO/S calculations taking configuration interactions into consideration. The photolysis index for one-electron transition ([DELTA]Mij) strongly suggested that photo-induced cyclization proceeds via an excited singlet state.
Key words: photodegradation of diniconazole, molecular orbital calculations, nuclear spin-lattice relaxation time, photolysis index.
Fungicidal Activities of alpha-Methoxyphenylacetic Acid Derivatives
A number of alpha-alkoxyphenylacetic acid derivatives were synthesized and their fungicidal activities were examined. Studies of structure-activity relationships revealed strong fungicidal activity when the substituent at the alpha-position was a methoxy group and a substituted phenoxymethyl group was introduced to the 2-position of the benzene ring of the phenylacetic acid moiety. When a substituted phenoxy group was introduced to this position, the fungicidal activity was very weak. It was also shown that N-methyl-phenylacetamide derivatives had stronger activities than phenylacetic acid methyl ester derivatives. Among the compounds synthesized in this study, 2-[2-(2,5-dimethylphenoxymethyl)phenyl]-2-methyl-N-methylacetamide (35) showed the most potent fungicidal activity against a wide range of crop diseases.
Key words: alpha-methoxyphenylacetic acid derivatives, fungicide, strobilurin analogue.
Controlling Efficacy of Strobilurin Derivatives against Wheat Powdery Mildew and Eyespot
Strobilurins are active against a wide range of diseases in laboratory tests, but do not always show the same level of activity under field conditions. We studied the differences in fungicidal activity under laboratory and field conditions of strobilurins and DMIs (14-demethylation inhibitor of elgosterol biosynthesis pathway) against wheat powdery mildew and eyespot, focussing on the systemicity of the compounds. Against wheat powdery mildew, the activity of the test compounds in the field differed from that in the laboratory. In the field, kresoxim-methyl, (E)-2-[2-(3-trifluoromethyl-5-chloropyridin-2-yloxymethyl)phenyl]-2-methoxyimino-N-methylacetamide and triadimefon, which have high level of both systemic activity and vapor-phase activity, showed excellent efficacy to control wheat powdery mildew. The effect is presumably due to the uniform coverage of the leaf surface, even leaves that emerged and developed after fungicide application. On the other hand, against wheat eyespot, (E)-2-[2-(2,5-dimethylphenoxymethyl)phenyl]-2-methoxyimino-N-methylacetamide (SSF-129) and prochloraz showed excellent activity in the field, despite being ineffective against powdery mildew. These compounds had strong mycelial growth inhibitory activity, limited systemic activity and no vapor-phase activity. Therefore, it is assumed that these two fungicides remain in the area where they are sprayed, and show excellent control of eyespot, the symptom of which develop in a limited area of the stem base of wheat seedlings.
Key words: methoxyiminoacetamide derivatives, fungicide, strobilurin analogue, wheat powdery mildew, wheat eyespot.
Influence of 1,3,5-Triazine Compounds on Ammonia Oxidizing Activity of Cell-Free Extracts from Nitrosomonas europaea
Key words: 1,3,5-triazine, Nitrosomonas europaea, ammonia monooxygenase.
A New Approach to the Study of Bound Residues in Plants; Incorporation of Tritium-Labeled 3-Phenoxybenzoic Acid into Cell Wall Components of Cypress
Key words: bound residues, autoradiography, 3-phenoxy-benzoic acid, cypress.
Differential Inhibition of a Melanin Biosynthetic Enzyme Scytalone Dehydratase by Carpropamid, a Fungicide for Rice Blast Control, and Its Isomers
Key words: rice blast fungus Pyricularia oryzae, scytalone dehydratase, melanin biosynthesis, carpropamid isomer, tight-binding inhibitor.
Evaluation of Affinity of Neonicotinoid Insecticides for Rat Brain Nicotinic Acetylcholine Receptors by [３H]Epibatidine-Binding Assay
Key words: neonicotinoid insecticide, nicotinic acetylcholine receptor, epibatidine, rat brain.
Synthesis and Electron-Transfer Activity of Azido Ubiquinone-2
Key words: azido quinone, ubiquinone, NADH-ubiquinone oxidoreductase, photoaffinity labeling.
Insect Growth Factor
Key words: insect, growth factor, paralytic peptide, growth blocking peptide, ecdysteroid, juvenile hormone.
Biomonitoring for Environmental Chemicals
Key words: environmental chemicals, bioassay, enzyme assay, receptor assay, immunoassay, antibody.
Studies on Three-Dimensional Quantitative Structure-Activity Relationships in Pesticides
Key words: 3D-QSAR, CoMFA, pyrethroids, GABA antagonists, neonicotinoids, PSII inhibitors.
Development of a New Herbicide, Sulfosulfuron
Key words: sulfosulfuron, sulfonylurea, herbicidal activity, imidazo[1,2-a]pyridine, Bromus tectrum L.
Discovery and Development of Pyriminobac-methyl
-- A Novel Herbicide --
Key words: pyriminobac-methyl, ALS, herbicide, barnyardgrass.
Development of a New Herbicide, Fentrazamide
Key words: carbamoyltetrazolinones, N-selective carbamoylation, Echinochloa spp., selectivity to rice, fentrazamide, herbicide.
Evaluation of Agonist and Antagonist Activities against Nicotinic Acetylcholine Receptors
Key words: nicotinic acetylcholine receptor, voltage clamp electrophysiology, agonist activity, antagonist activity.
Vol. 27, No. 1, p. 62 (2002)
The “mg･mL(-1)” should be corrected to “[micro]g･mL(-1),” because of the mistake of the authors.
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