Combinatorial chemistry has become an important tool in both drug discovery and chemical biology and its continued success is dependent, in part, on further advances in solid-phase organic synthesis (SPOS). This paper describes recent findings and a useful method for the synthesis of heterocycle and nitrogen heterocycle compounds. © Pesticide Science Society of Japan

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Concentrations of esprocarb, thiobencarb, dimethametryn, pretilachlor and simetryn in water, suspended solids and sediment were studied during ordinary water discharge over the course of a year in Sugao marsh, Ibaraki Prefecture, Japan. Periodic changes in pesticide concentrations in water were similar to those in suspended solids. Pesticides were mostly present as dissolved form in water. Namely, the partition ratios of total suspended solids in whole water samples were 0.37–2.5% as the median, and the ratios of pesticide loading as adsorbed form on suspended solids against total pesticide loading were 0.42–4.6%. However, the concentrations of pesticides were higher in fine suspended solids (0.5 to 1.0 μm) than coarse suspended solids (more than 1.0 μm). Fine suspended solids loaded with pesticides were estimated to be 18 to 59% of all suspended solids, indicating their important role as a carrier of pesticides. Moreover, vertical distributions of pesticides in sediment down to a depth of 15 cm were not clearly shown, probably due to the disturbance of sediment at the surface by actual water flow. © Pesticide Science Society of Japan

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N-Substituted and N,N-disubstituted 2,4-dihydroxythiobenzamides were synthesized and their fungistatic properties were examined. The compounds were prepared by reacting sulfinyl-bis-(2,4-dihydroxythiobenzoyl) with primary or secondary amines. The activities of the derivatives against five phytopathogenic fungi were measured in vitro. The growth-inhibitory activity of these compounds depends mainly on their lipophilicity. Parabolic relationships between growth-inhibitory activity and lipophilicity (calculated n-octanol-water partition coefficient and log k_w from reversed phase chromatography) were found. The influence of the type of N-substitution on the character of the thioamide bond was analyzed based on ¹H NMR, MS and IR spectra. © Pesticide Science Society of Japan

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We compared the chemical (fungicide; azoxystrobin) exposure while spraying persimmon trees pruned in the shape of a table (table-shaped method) with that while spraying trees pruned in the typical standing-tree shape. Exposure was evaluated using 9 patches attached to the body of each of 4 test subjects. Furthermore, we measured the vertical range of spraying which affects the amount of exposure, to estimate primary contamination, and the frequency of contact with branches or leaves to estimate secondary contamination. The results showed that the table-shaped method was useful in reducing primary and secondary contamination and reduced the level of chemical exposure. © Pesticide Science Society of Japan

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The herbicidal activity and properties of a diphenylpyrrolidinone, MT-141 [4-ethyl-3-(3-fluorophenyl)-1-(3-trifluoromethylphenyl)pyrrolidin-2-one], were examined. MT-141 controlled barnyardgrass (Echinochloa crus-galli), johnsongrass (Sorghum halepense), green foxtail (Setaria viridis), large crabgrass (Digitaria sanguinalis), fall panicum (Panicum dichotomiflorum), goosegrass (Eleusine indica), and broadleaf signalgrass (Brachiaria platyphylla) at 300 g a.i./ha when applied pre-emergence (PRE), and provided greater than 90% control of these weed species at 500 g a.i./ha when applied post-emergence (POST). MT-141 was less effective against broad-leaved plants such as velvetleaf (Abutilon theophrasti) and ivyleaf morningglory (Ipomoea hederacea), but two other broad-leaved plants, hemp sesbania (Sesbania exaltata) and prickly sida (Sida spinosa), were slightly susceptible to MT-141. MT-141 applied PRE at 500 g a.i./ha did not injure cotton. The most significant herbicidal symptom for this compound was bleaching. Residual activity of MT-141 applied PRE to barnyardgrass and johnsongrass lasted at least 5 weeks. Planting depth or soil type did not affect the herbicidal activity of MT-141 at 300 g a.i./ha. MT-141 applied PRE increased the herbicidal activity of glyphosate against hemp sesbania and morningglory without injuring glyphosate-resistant cotton. Also several surfactants increased the herbicidal efficacy of this compound on POST application. MT-141 seems to be an effective herbicidal compound for controlling graminaceous weeds when applied PRE in cotton production. © Pesticide Science Society of Japan

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The actions of neonicotinoid insecticides on nicotinic acetylcholine receptors (nAChRs) in the terminal abdominal ganglion neurons of the American cockroach were investigated using whole-cell patch-clamp electrophysiology. Neonicotinoids possessing a nitromethylene group showed higher agonist affinity than the corresponding nitroimine analogues, whereas compounds with an acyclic guanidine moiety showed greater agonist efficacy than the corresponding cyclic compounds. Imidacloprid showed the lowest agonist efficacy of all neonicotinoids and low concentrations of imidacloprid attenuated acetylcholine-induced currents. However, such blocking actions were minimal with other neonicotinoids. The diverse actions of neonicotinoids on nAChRs, combined with target accessibility based on hydrophobicity, appears to account for their insecticidal potency on cockroaches measured in the presence of metabolic inhibitors. © Pesticide Science Society of Japan

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Microbial culture broths were screened for novel β-N-acetylglucosaminidase (GlcNAcase) inhibitors specific for the enzyme of insect origin. Four strains of actinomycetes, Streptomyces griseoloalbus JCM4480, S. clauifer JCM5059, S. anulatus NBRC13369 and S. griseus subsp. rhodochrous NBRC13849, produced unique compounds showing selective inhibition of the insect GlcNAcase. In contrast, 4 fungal strains, Paecilomyces sp. F13, F30, P. carneus F2281 and Verticillium sp. F40, were found to produce GlcNAcase inhibitors showing a broad spectrum of inhibitory activity against GlcNAcases from insects, mammals, plants and fungi. These results indicated obvious differences in GlcNAcases between insects and other organisms. This is the first report of enzyme inhibitors specific for the GlcNAcase of insect origin. © Pesticide Science Society of Japan

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A putative O-methyltransferase cDNA was cloned from UV-irradiated rice leaves based on an amino acid sequence reported as that of naringenin 7-O-methyltransferase, which is involved in the biosynthesis of a rice phytoalexin, sakuranetin. However, the recombinant protein (approximately 41 kDa) expressed in Escherichia coli showed not naringenin 7-O-methyltransferase activity but caffeic acid 3-O-methyltransferase activity. Semi-quantitative RT-PCR revealed that the mRNA was expressed in all tissues tested and was not affected by CuCl₂, jasmonic acid or UV treatment. The enzyme also methylated flavonoids which have two adjacent hydroxyl groups in the B ring. © Pesticide Science Society of Japan

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