The metabolic fate of 5-4068SF [Etoc®, (S)-2-methyl-4-oxo-3-(2-propynyl)cyclopent-2-enyl (1R)-trans, cis-chrysanthemate], a novel pyrethroid, was examined by administering [alcohol-¹⁴C](4S, 1R)-trans- and [alcohol-¹⁴C] (4S, 1R)-cis-S-4068 orally or subcutaneously to male and female rats at 2mg/kg. The administered radiocarbon was almost completely eliminated in urine and feces within 7 days after treatment. ¹⁴C levels in blood and other tissues reached maxima within 3hr after oral administration and thereafter decreased rapidly. Biological half-lives of ¹⁴C tissue levels for 3-12 and 12-48hr after oral administration were 3-5hr and 7-35hr, respectively. ¹⁴C tissue residues were generally very low on the 7th day after administration. Twenty metabolites found in excreta were identified. Proposed metabolic pathways of S-4068SF involved, 1) oxidation at methyl of the isobutenyl group in the acid moiety and at the C-1 or the C-2 position of the propynyl group in the alcohol moiety, 2) cleavage of ester linkage, and 3) conjugation of resultant hydroxy derivatives with glucuronic acid and sulfuric acid. There was no marked difference in the metabolic fate of (4S, 1R)-trans- or (4S, 1R)-cis-S-4068 between sexes and administration routes.

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The degradation of pyrazolate was studied in soils under laboratory conditions by using ¹⁴C-preparations labeled separately at the pyrazole and chlorinated benzene rings. Pyrazolate was hydrolyzed at the ester bond to give p-toluenesulfonic acid (PTSA) and the herbicidal entity, 4-(2, 4-dichlorobenzoyl)-1, 3-dimethyl-5-hydroxypyrazole (DTP). The half-lives in two soils under flooded conditions were about 10 days. PTSA labeled with ¹⁴C at the benzene ring was rapidly mineralized to CO₂, while DTP was relatively persistent in soils. DTP underwent oxidation at the 1- and 3-methyl groups, cleavage of the benzoyl bond, fission of the pyrazole and benzene rings, and was ultimately mineralized to CO₂.

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Absorption, translocation and metabolism of DTP [4-(2, 4-dichlorobenzoyl)-1, 3-dimethyl-5-hydroxypyrazole], the hydrolysate and herbicidal entity of pyrazolate, in rice plants was studied by using ¹⁴C-preparations labeled either at the pyrazole ring or at the benzene ring under a water-culture condition. DTP was readily absorbed into the roots, rapidly metabolized and part of the radioactivity was translocated into the foliages. The metabolism of DTP involved hydroxylation of the 3-methyl group and subsequent oxidation to carboxyl group, demethylation of the 1-methyl group, cleavage of 2, 4-dichlorobenzoyl linkage, and conjugation.

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For 30 N-(3, 4-diethoxyphenyl)carbamoyl esters with various alcoholic moiety substituents, their fungicidal activity against Botrytis cinerea resistant to benzimidazole fungicides was determined by the agar medium dilution method and the structure-activity relationships were analyzed by using the multiple regression technique. The hydrophobicity of the substituents was favorable to the activity. The activity was related parabolically to the maximum width of the substituents and the “β-branching” of the substituents was detrimental to the activity. The preventive activity of compounds against gray mold of cucumber caused by the resistant B. cinerea was determined by the foliar application in pot tests. The preventive activity was dependent on the magnitude of the fungicidal activity and the α-branching of the substituents on analysis by the adaptive least-squares method.

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A number of alkoxysulfenyl derivatives of insecticidal methylcarbamates were synthesized by the reaction between alcohols and N-chlorosulfenyl-N-methylcarbamate, the latter being prepared from the methylcarbamate and sulfur dichloride in the presence of base. Polysulfide analogs of the alkoxysulfenyl derivatives were also formed in significant amounts as byproducts by this method. The alkoxysulfenyl derivatives of phenyl carbamates proved to be stable, whereas the derivatives of oxime carbamates were unstable. All of the alkoxysulfenyl derivatized carbamates, with a few exceptions, showed high insecticidal activity against houseflies and green rice leafhoppers. Some of the derivatives of carbofuran (2, 3-dihydro-2, 2-dimethyl-7-benzofuranyl N-methylcarbamate) appeared more effective against houseflies than the parent carbofuran. Derivatization generally resulted in substantial improvement in toxicity to mice. Toxicity of the derivatives of carbofuran to mice systematically decreased with increase in carbon atoms in the straight chain alkoxy moiety. All the polysulfide analogs were insecticidal, and both the activity to houseflies and the toxicity to mice decreased with increase in the number of sulfur atoms in the molecule.

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We present an efficient approach to the chiral synthesis of podoblastins A, B and C, potent antifugal constituents obtained from Podophyllum peltatum L., against Pyricularia oryzae (rice blast). Optically pure podoblastins A, B and C ((6R)-(-)- and (6S)-(+)-3-acyl-5, 6-dihydro-6-propyl-2-pyrones) were synthesized from the corresponding, (R)-(-)- and (S)-(+)-glycerol derivatives, respectively, which are readily available as chirons. Both enantiomer of unnatural podoblastin S (3-decanoyl-5, 6-dihydro-6-propyl-2-pyrone), which are expected to reveal more effective antifungal activity than those of natural products, were also synthesized in the same manner. The synthesized compounds were tested against rice blast. The absolute stereochemistry of podoblastins A, B and C was confirmed to be (R). Synthetic compound, (R)-(-)-podoblastin S was the most effective in prevention.

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Droplets of heavy metal salts (1mM) were applied to holes punctured by a glass capillary tube on the surfaces of detached rice leaves, and the accumulation of phytoalexins in tissues surrounding the holes and in droplets were quantitated with gas chromatography-mass spectrometry-selected ion monitoring (GC-MS-SIM). This analytical method was highly sensitive and accurate, minimizing material and time requirements. Copper ion treatment induced two diterpenoid phytoalexin groups of rice plants, i. e., oryzalexins A, B, C, and D, and momilactones A and B. These phytoalexins differed in diffusion rates from leaves into droplets. Among the momilactones, momilactone A showed a marked induction. Among the oryzalexins, oryzalexin B was induced to the greatest extent. The accumulation of momilactone A was first noted 12hr after application of copper ion, reaching maximum after 72hr. As these phytoalexins accumulated brown spots appeared in areas surrounding the punctured holes. Iron and mercury ions made up approximately 37% and 20% of the elicitor activity of copper ion, respectively. Manganese and cobalt ions hardly showed any elicitor activity.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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