Effect of halomethyl-1,3,5-triazines on nitrification of ammonia

Nitrification inhibitory activity of halomethyl-1,3,5-triazines was determined by measuring the inhibitory activities on ammonia-oxidation to nitrate (NO₃⁻-N) in an upland soil and on ammonia-oxidation to nitrite (NO₂⁻-N) by Nitrosomonas europaea ATCC 25978 (ATCC) and Nitrosomonas sp TK 794 (TK). Within the chlorinated trimethyl-1,3,5-triazines, those bearing at least one trichloromethyl group inhibited nitrification more strongly, both in soil and in cell suspension of ATCC, than other mono- or dichlorinated methyl-1,3,5-triazines. Introduction of an amino group to 2,4,6-tris(trichloromethyl)-1,3,5-triazine gave 10- and 100-fold increases of nitrification inhibitory activity in soil and ATCC cell culture, respectively. Within the trihalomethyl-1,3,5-triazines, those having tribromomethyl group(s) exhibited rather weaker nitrification inhibition in soil than the corresponding trichloromethyl-1,3,5-triazines, although they showed a strong inhibition in cell suspension. Ammonium oxidation in ATCC was inhibited more strongly than that in TK. In QSAR studies, the optimum log P values were calculated as c 4.30. By using this value it will become possible to design highly active trichloromethyl-1,3,5-triazine nitrification inhibitors.     

The analysis of crops and soils for the triazine herbicide cyanazine and some of its degradation products. I. Development of method

Radiochemical techniques have been used to develop efficient procedures for the extraction of residues of cyanazine herbicide [‘BLADEX’,

1 BLADEX and FORTROL are Shell registered Trade Marks.

^a ‘FORTROL’,^a 2-chloro-4-(1-cyano-1-methylethylamino)-6-ethylamino-1,3,5-triazine] and its metabolites 2-chloro-4-(1-carbamoyl-1-methylethylamino)-6-ethylamino-1,3,5-triazine ( II ), 2-chloro-4-(1-cyano-1-methylethylamino)-6-amino-1,3,5-triazine ( V ) and 2-chloro-4-(1-carbamoyl-1-methylethylamino)-6-amino-1,3,5-triazine ( VI ) from crops and soils. Partition and column chromatographic techniques have been established for the purification of the extracts. The full analytical procedure is described and the final determination of all four compounds is by g.l.c. with electron capture detection with blank values for field samples generally 0.02 part/million and with good recoveries.     

Quantitative bioassays for determining residues and availability to plants of sulphonylurea herbicides

A bioassay procedure for quantitative determination of sulphonylurea herbicides is described. Turnips (Brassica rapa) were found very suitable as test plants and gave results within 10 days. Six sulphonylurea compounds were investigated for their activity in three widely differing soils. The potential availability to plants was calculated from the dose-response curves of vermiculite (non-sorptive substrate) and the corresponding ED₅₀-values of the soils. The dose-response relationship (logistic curve) was described by a computer model by a position parameter, the slope of the curve and the minimum and maximum fresh weights of plants. The limit of quantitative detection in the range of ED₃₀ in vermiculite was 0·06 μg 1^?1 for sulfometuron and 1·03 μg 1^?1 for DPX-L5300, methy12-([4-methoxy-6-methyl-1,3,5-triazin-2-yl (methyl)carbamoyl]-sulphamoyl) benzoate. Results with turnips showed that sulfometuron was the most active compound in all substrates (ED₅₀ in vermiculite 0·12 μg 1^?1) followed by chlorsulfuron, metsulfuron-methyl, triasulfuron, DPX-M6316, methyl 3-([(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbamoyl]-aminosulphaphamoyl)-2-thiophenecarboxylate, and DPX-L5300 which had ED₅₀ or 1·98 μg 1^?1, The Horotiu sandy loam soil showed the highest ED₅₀-values and the lowest plant availability for all compounds compared to the other soils. Probit and logistic evaluation methods for deriving dose-response relationships are compared and their applicability is discussed.     

Inhibition of chitin biosynthesis by buprofezin analogs in relation to their activity controlling Nilaparvata lugens Stål

Buprofezin (Applaud, 2-tert-butylimino-3-isopropyl-5-phenyl-3,4,5,6-tetrahydro-2H-1,3,5-thiadiazin-4-one) strongly inhibited the [³H]chitin synthesis from N-acetyl-d-[1-³H]glucosamine in the brown rice planthopper, Nilaparvata lugens Stål. No inhibition was observed for [³H]-labeled protein biosynthesis from [5-³H]glucose or l-[3,5-³H]tyrosine but [³H]-labeled nucleic acid synthesis from [5-³H]glucose was weakly reduced by buprofezin. The lethal activity of buprofezin analogs related well to their inhibitory potency against chitin biosynthesis in N. lugens nymphs.     

Synthesis and fungitoxic activity of 5‐aryl‐1‐formyl‐4,5‐dihydro‐3‐(2‐hydroxyphenyl)‐1H‐pyrazoles and their complexes

Cyclization of 3‐aryl‐1‐(2‐hydroxyphenyl)prop‐2‐en‐1‐ones with hydrazine hydrate in refluxing formic acid afforded the title ligands, 5‐aryl‐1‐formyl‐4,5‐dihydro‐3‐(2‐hydroxyphenyl)‐1H‐pyrazoles (HL¹–HL⁴, Ar = Ph, 4‐CH₃O‐C₆H₄‐, 2‐furyl, 2‐thienyl). Reaction of HL¹–HL⁴ with the divalent metal ions, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺, afforded novel complexes of the type [ML₂] (M = metal ion; L = deprotonated ligand) which were characterized by elemental analyses, molecular weight determinations, molar conductances, magnetic moments and electronic and infrared spectral data. The ligands behaved as tridentate, coordinating through the phenolic oxygen after deprotonation, N‐2 of the pyrazole ring and oxygen of the 1‐formyl group. The ligands and their complexes were evaluated for growth‐inhibiting activity against four phytopathogenic fungi. Macrophomina phaseoli was generally most sensitive followed by Alternaria alternata and Colletotrichum falcatum while Fusarium oxysporum was least sensitive to the tested compounds. The ligand HL¹ and its complexes showed the best activity against the fungi tested. © 2000 Society of Chemical Industry     

Acaricidal activity of triketone analogues derived from Leptospermum scoparium oil against house‐dust and stored‐food mites

BACKGROUND: Various attempts to control the populations of house‐dust and stored‐food mites have been implemented using synthetic chemicals. Although effective, the repeated use of these chemicals has led to resistance owing to the mite's high reproductive potential and short life cycle. Therefore, this study aimed to develop natural acaricides using oils derived from Leptospermum scoparium JR & G Forst., which may affect the overall biological activity of a mite without adverse effects. Results were compared with those from using benzyl benzoate and N,N‐diethyl‐3‐methylbenzamide (DEET). RESULTS: The LD₅₀ values of L. scoparium oil were 0.54, 0.67 and 1.12 µg cm^?2 against Dermatophagoides farinae (Hughes), D. pteronyssinus (Troussart) and Tyrophagus putrescentiae (Schrank) respectively. The active constituent isolated from L. scoparium was identified as leptospermone (6‐isovaleryl‐2,2,4,4‐tetramethyl‐1,3,5‐cyclohexanetrione) by spectroscopic analysis. Based on the LD₅₀ values of leptospermone and its derivatives, the most toxic compound against D. farinae was leptospermone (0.07 µg cm^?2), followed by 2,2,4,4,6,6‐hexamethyl‐1,3,5‐cyclohexanetrione (1.21 µg cm^?2), benzyl benzoate (10.03 µg cm^?2) and DEET (37.12 µg cm^?2). Furthermore, similar results were observed when the leptospermone and its derivatives were tested against D. pteronyssinus and T. putrescentiae. CONCLUSIONS: These results indicate that L. scoparium oil‐derived materials, particularly leptospermone and 2,2,4,4,6,6‐hexamethyl‐1,3,5‐cyclohexanetrione, have potential for development as new agents for the control of three species of mite. Copyright © 2008 Society of Chemical Industry     

Cyanazine metabolism in corn,fall panicum,and green foxtail*

The metabolism of cyanazine (2-chloro-4-(1-cyano-1-methyl-ethylamino)-6-ethylamino- 1,3,5-triazine) by corn (Zea mays, L.), fall panicum (Panicum dichotomiflorum Michx.), and green foxtail (Setaria viridis L.) was compared. Cyanazine metabolism by plants at the four-leaf stage was examined by thin-layer chromatography following foliar or root treatments with ¹⁴C-cyanazine. Five days following foliar ¹⁴C-cyanazine applicalion, fall panicum and green foxtail contained a larger number of water- and chloroform-soluble metabolites than corn, whereas, following root treatment, the opposite was true. Corn rapidly hydrolysed the nitrile group and hydroxylated the two-position on the triazine ring. Accumulation of the dealkylated cyanazine was evident in green foxtail, the most susceptible of the species studied. Metabolism of cyanazine supplied to the roots appeared to differ from foliar treatments in the weed species as more unchanged cyanazine was recovered. Rapid metabolism of cyanazine by corn roots provided evidence for an active cyanazine detoxication mechanism in the roots.     

Effects of N, P and K on Striga asiatica (L.) Kuntze seed germination and infestation of sorghum

Sorghum (Sorghum bicolor (L.) Moench) plants were grown in pots with 12.5 and 50 mg applied N kg^?1 soil. With an increase of soil N, the Striga asiatica (L.) Kuntze infestation, as well as the sorghum shoot dry matter losses due to infestation, decreased. The relative differences in stimulant capacity to induce Striga seed germination among the four sorghum genotypes were not consistent over the 0 to 150 mg N 1^?1 range. The sorghum root exudate was considerably more active at 0 mg N 1^?1, than at 30 mg N 1^?1, and the stimulant produced at 150 mg N 1^?1 failed to induce Striga seed germination. Presence of N in the growth medium considerably reduced the effectiveness of the stimulating substance produced by sorghum roots, whereas K promoted stimulant activity only in the absence of N. The presence or absence of P in the growth medium did not affect Striga seed germinability, probably due to the inability of this element to interfere with the production or activity of the stimulating substance from the host plants. It can be concluded, therefore, that sorghum plants seem to produce active root exudate only in conditions of N deficiency.     

Design, synthesis, insecticidal activity and structure-activity relationship of 3,3-dichloro-2-propenyloxy-containing phthalic acid diamide structures

BACKGROUND: Phthalic acid diamide derivatives are among the most important classes of synthetic insecticides. In this study, a 3,3‐dichloro‐2‐propenyloxy group, the essential active group of pyridalyl derivatives, was incorporated into phthalic acid diamide derivatives with the aim of combining the active groups to generate more potent insecticides. RESULTS: Thirty‐one new phthalic acid diamides were obtained, and these were characterised by ¹H and ¹³C NMR. The structure of N²‐[1,1‐dimethyl‐2‐(methoxy)ethyl]‐3‐iodo‐N¹‐[4‐(3,3‐dichloro‐2‐propenyloxy)‐3‐(trifluoromethyl)phenyl]‐1,2‐benzenedicarboxamide was determined by X‐ray diffraction crystallography. The insecticidal activities of the compounds against Plutella xylostella were evaluated. The title compounds exhibited excellent larvicidal activities against P. xylostella. Structure‐activity relationships revealed that varying the combination of aliphatic amide and aromatic amide moieties, or the nature and position of substituent Y on the aniline ring, could aid the design of structures with superior performance. CONCLUSION: A series of novel phthalic acid diamides containing a 3,3‐dichloro‐2‐propenyloxy group at the 4‐position of the aniline ring were designed and synthesised. Structure‐activity relationships with the parent structure provided information that could direct further investigation on structure modification. Copyright © 2012 Society of Chemical Industry     

A root bioassay procedure for the determination of chlorsulfuron, diclofop acid and sethoxydim residues in soils

Measurement of the root lengths of pre-ger-minated oat seedlings (Avena sativa L. var. Sioux) grown in the dark in treated soils was used to assay residues of diclofop acid (2-[4-(2,4-dichloro-phenoxy)phenoxy]propionate) and sethoxydim (2-[1-(ethoxyimino)-butyl]-5-[2-(ethylthio)-propy]-3-hydroxy-2-cyclohexene-1-one). Similar measurements involving maize seedlings (Zea Mays L. var. Sunny Vee) were also used to determine residues of the herbicide chlorsulfuron (2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbony]benzenesulfonamide) in soils. The procedure appeared to be reproducible with residues of chlorsulfuron, diclofop acid and sethoxydim being detectable at amounts of 0.001, 0.2 and 0.05 μg g^?1 respectively.     

Bicyclophosphorothionate antagonists exhibiting selectivity for housefly GABA receptors

2,6,7-Trioxa-1-phosphabicyclo[2.2.2]octane 1-sulfides (bicyclophosphorothionates) with various C_1–4 alkyl groups at the 3- and 4-positions were synthesized and tested for their ability to compete with [³H]4′-ethynyl-4-n-propylbicycloorthobenzoate (EBOB), a non-competitive antagonist of γ-aminobutyric acid (GABA) receptors, for specific binding to rat-brain and housefly-head membranes, and for their insecticidal activity against houseflies. Among the 3,4-substituted analogues, 20 compounds were selectively active for housefly GABA receptors versus rat GABA receptors. The 3-alkyl groups of C₃ length and the 4-alkyl groups of C₄ length were tolerated in housefly receptors, whereas such bulky substituents were deleterious in rat receptors. The 4-isobutyl-3-isopropyl analogue was the most potent in housefly receptors (IC₅₀ = 45.2 nM ), and tert-butylbicyclophosphorothionate (TBPS), with the 4-tert-butyl group and no 3-substituent, was the most potent in rat receptors (IC₅₀ = 62.2 nM ). Their receptor selectivities (rat IC₅₀/housefly IC₅₀) were 52 and 0.038, respectively. The insecticidal activity (LD₅₀) of 20 active analogues was well correlated with their potency (IC₅₀) in inhibiting [³H]EBOB binding to housefly-head membranes (r = 0.93). The results obtained in the present study indicate that the introduction of appropriate alkyl groups into the 3- and 4-positions of bicyclophosphorothionate leads to non-competitive antagonists with increased affinity and selectivity for housefly ionotropic GABA receptors versus rat GABA_A receptors. © 1999 Society of Chemical Industry     

(E)-O-芳酰基-α-氧代环十二酮肟的合成及除草活性

以环十二酮为原料 ,制得中间体 (E) -α-氧代环十二酮肟 (Ⅳ)后 ,经酰化合成了九个 (E) - O-芳酰基 -α-氧代环十二酮肟 (Ⅴ) ,它们的结构得到元素分析、IR和 1HNMR的确证。生测结果表明 ,部分化合物具有良好的除草活性。对活性较高的 3还通过精密毒力测定 ,求得 IC50 值。中间体 在贝克曼反应条件下发生断裂反应生成 11-氰基十一酸 (Ⅶ) ,证实了 具有 (E) -构型的结构特征。     

Effect of substituted pyrazoles and related compounds on geotropism in cress seedlings

The effects on root geotropism of three series of compounds related to 2-phenyl-8H-pyrazolo[5,1-a]isoindol-8-one (IV), its 3,3a-dihydro derivative (V) and 5-(2-carboxyphenyl)-3-phenylpyrazole (VI) have been assessed using cress seedlings. Compounds (IV) and (VI), and their derivatives, are highly active, destroying geotropism at concentrations of 10^?7-10^?9M. Substitution with various functional groups and increased molecular size resulted in only minor variation in the level of activity.     

Production,size, and germination of broad‐leaved dock seeds collected from mother plants grown under different nitrogen,phosphorus, and potassium supplies

Rumex obtusifolius is believed to be a nitrophilous weedy species that spreads mainly by seed. However, the effects of nutrient availability on seed production never have been investigated. In this study, how the amount of seed production per plant, the chemical composition of the seeds, and their size and germination are affected by the supply of N, P, and K was investigated. A pot fertilizer experiment with 10 treatments (combinations of 0, 150 [N1], and 300 [N2] kg N ha^?1, 0, 40 [P1], and 80 [P2] kg P ha^?1, and 0 and 100 [K] kg K ha^?1 applied twice per vegetation season) was carried out in Prague, Czech Republic, in 2008 and 2009. The seeds from plants that were cultivated since the spring were collected each August. The germination of the seeds was determined in long‐daylight conditions at a stable temperature of 20°C. The number of seeds per plant ranged from 0 in the P1 and P2 treatments and <200 in the control and K treatments to almost 9000 in the N2P2K treatment. The number of seeds per plant was positively correlated with the number of stems per plant and the number of seeds per stem. The relationship between the amount of seeds per plant and the individual seed weight was positive. The concentration of N, P, and K in the seeds was affected by the treatments. The weight of 1000 seeds ranged from 1.3 to 1.7 g. The seed length ranged from 2.11 to 2.34 mm and the seed width varied from 1.26 to 1.42 mm. With the exception of the control (with 94% germination), the amount of seed germination was >98% in all the other treatments in 2008. In 2009, the amount of seed germination was >95% in all the treatments, except N1 and N2, where 93% and 89% germination, respectively, was recorded. The germination rate was positively related to the P concentration in the seeds. The amount of time that was necessary for 50% seed germination ranged from 1.53 to 2.89 days and was not related to the N concentration in the seeds, but it was negatively related to the P and K concentrations. A balanced N, P, and K supply to the mother plant strongly affected the number of produced seeds and their chemical composition and germination ability.     

Measurement of simazine residues in chickpeas,Cicer arietinum,by gas–liquid chromatography

A method is described for the measurement of simazine [2-chloro-4,6-bis(ethylamino)-1,3,5-triazine] residues in chickpeas (Cicer arietinum). Ground chickpea samples were extracted with dichloromethane, followed by clean-up on alumina. Gas-liquid chromatography using metribuzin [4-amino- 6-tert-butyl-4,5-dihydro-3-methylthio-1,2,4-triazin-5-one] as internal standard with thermionic detection was used to quantify simazine residues. The limit of detection was 0.02 mg kg^?1 and the recoveries of simazine from chickpea samples (0.1–4 mg kg-1) averaged 92%.     

New melanin biosynthesis inhibitors and their structural similarities

Relationships between their activities as blast control agents, and their abilities to inhibit mycelial melanisation on a nutrient agar, are described for 103 substituted benzothiazol-2(3H)-ones, benzoxazol-2(3H)-ones, indolin-2-ones, quinolin-2(1H)-ones, 1,2,3,4-tetrahydroquinolin-2-ones, benzo-1,4-thiazin-3(2H)-ones and benz-1,4-oxazin-3(2H)-ones, and some corresponding thiones. Several compounds in the respective series had a high protective activity and an antimelanisation activity against the blast fungus Pyricularia oryzae; furthermore, there was a good correlation in both of these activities, indicating that these compounds belong to the group of melanin biosynthesis inhibitors. Structural similarities of these compounds can be identified as follows: (a) having a benzo-bicyclic ring system; (b) containing a nitrogen atom in one ring at a position alpha to the benzene ring system; and (c) substitution, at the ring nitrogen atom, at the peri position in the aromatic ring relative to the nitrogen atom, and at the position alpha to the nitrogen atom in the ring system, with a double bond such as in carbonyl and thiocarbonyl groups. Among the compounds that have been proposed as melanin biosynthesis inhibitors, the chemical structures of tricyclazole, pyroquilon, 4,5-dihydro-4-methyltetrazolo[1,5-a]quinazolin-5-one (PP-389), [1,2,4]-triazolo[4,3-a]quinoline and 1-methylquinolin-2(1H)-one exhibit the structural similarities described above; however, 4,5,6,7-tetrachlorophthalide, 2,3,4,5,6-pentachlorobenzyl alcohol and N-substituted-2,3,4,5-tetrachloro-6-(hydroxymethyl)benzamides do not have such similarities in their chemical structures.     

The breakdown of the triazine herbicide cyanazine in wheat and potatoes grown under indoor conditions in treated soils

The breakdown of the triazine herbicide cyanazine (“BLADEX”,^a 2-chloro-4-(1-cyano-1-methylethylamino)-6-ethylamino-1,3,5-triazine) has been studied in spring and winter wheat and potatoes grown under indoor conditions in soils treated at planting with up to 1.5 kg/ha of the radiolabelled herbicide. Breakdown products were mainly those formed by hydrolysis of the cyano group to give an amide ( II ) and an acid ( III ) followed by hydrolysis of the chlorine to hydroxyl ( IV ). De-N-alkylation reactions also occurred although these were less evident in soils. In wheat the chloro acid ( VII ) formed by the des-ethylation of ( III ) was more evident than in previous studies with maize. In all of the crops at harvest the residues were mainly of the hydroxy acids ( IV ) and ( VIII ); ( IV ) 2-hydroxy-4-(1-carboxy-1-methylethylamino)-6-ethyl-amino-1,3,5-triazine; ( VIII ) 2-hydroxy-4-(1-carboxy-1-methylethylamino)-6-amino-1,3,5-triazine, respectively. In potatoes and spring wheat they were present in both free and conjugated forms whereas in winter wheat they were almost entirely in conjugated forms. The compounds (IV) and (VIII) are of a low order of toxicity to animals and are not herbicidal. They are unlikely to present a residue hazard if present in field crops.     

Effects of juvenile hormone analog formulations on development and reproduction in the bed bug Cimex lectularius (Hemiptera: Cimicidae)

BACKGROUND: Bed bugs (Cimex lectularius L.) have become a common insect pest in urban areas and are often difficult to manage. Eradication is made more problematic by widespread insecticide resistance, raising interest in alternative control products. Juvenile hormone analogs (JHAs) such as methoprene and hydroprene are relatively harmless to non‐arthropods and have proved to be effective against other urban insect pests. Two JHA products (Gentrol^® and Precor^®, Central Life Sciences, Schaumburg, IL) were tested for efficacy against various bed bug stages as direct spray and as dry residue using three bed bug strains. RESULTS: At 1× and 2× the label rate, Precor^® [active ingredient (S)‐methoprene] had no significant effect on the development or fecundity of bed bugs. At 2× the label rate, confinement to residues of Gentrol^® [active ingredient (S)‐hydroprene] had no significant effect, but residues at 3× and 10× the label rate caused a reduction in fecundity and impaired development. Field strains were more susceptible to the reproductive effects of (S)‐hydroprene than a long‐maintained laboratory strain. CONCLUSIONS: While JHAs are attractive alternatives for pest management because of their inherent safety and distinct mode of action, these JHA formulations would have little impact on bed bug populations without relabeling to allow for higher application rates. Copyright © 2012 Society of Chemical Industry     

Reductive and oxidative metabolism of triazolylmethanes by two basidiomycete fungi

The metabolism of [¹⁴C]triadimefon, triadimenol, diclobutrazol, and the oxo-analogue of diclobutrazol by the basidiomycete fungi Coriolus versicolor and Rhizoctonia solani was studied. Reduction of >C = 0 to >CHOH (activation) was more important for triadimefon than oxo-diclobutrazol. Conversely, oxidation of >CHOH to >C = 0 (deactivation) occurred to a greater extent with diclobutrazol than triadimenol. Formation of primary alcohol metabolites, a possible detoxication route, occurred more with diclobutrazol and its oxo-analogue than with triadimefon and triadimenol. The implications of the reduction/oxidation processes and primary alcohol formation on fungitoxicity of the applied triazolymethane are discussed. The enantiomeric composition of metabolically produced triadimenol is discussed in relation to the in vitro activity of triadimefon supplied against each fungus.