Cu(II) complexes of glycine-peptides, abbreviated as Cu(H−iL): L = glycylglycine, triglycine, tetraglycine, and pentaglycine (i = 1–3), react with cysteine to form ternary complexes, Cu(H−1L)(Cys−), as first intermediates. The spectral parameters of the ternary complexes, which were similar irrespective of the peptides, were as follows: λmax = 332 ± 1 nm (ε = 4250 ± 50 M−1 cm−1), g|| = 2.170 ± 0.005, g⊥ = 2.00 ± 0.05, and A|| = (2.05 ± 0.01) × 10−4 cm−1, indicating that the ternary complexes have identical coordination structures: the Cu(II) coordinates with the peptides via the nitrogens from the terminal amino and the neighboring deprotonated-amide group, and with cysteine via the amino nitrogen and the thiolate sulfur. Based on the absorbance-time curves, the concentrations of each Cu(II) and Cu(I) species during the reaction were calculated. The species distribution curve clearly visualized the pathway of the Cu(II) transport from Cu(H−iL) to Cu(Cys−)2 via Cu(H−1L)(Cys−). The rate of Cu(H−1L)(Cys−) formation, which was evaluated from the initial increase in the species distribution curve, depended on the coordination modes of the Cu(H−iL) complexes. Both the Cu(H−1L), involving N,N−,O−,O* donors, and the Cu(H−2L), involving N,N−,N−,O−* donors, rapidly formed Cu(H−1L)(Cys−) complexes, where the donors asterisked represent the fourth ligand in the Cu(H−iL) complexes. The second-order rate constant, k1+, was on the order of 106 M−1 s−1, or bigger. The Cu(H−3L), involving N,N−,N−,N−* donors, reacted relatively slowly; k1+ was on the order of 104 M−1 s−1. Those results indicate that the affinity of the Cu(II) for the fourth donor in Cu(H−iL) determines the rate of metal-transport.

No abstract

Pyrimisulfan is a novel sulfonanilide herbicide with high herbicidal activities against major troublesome weeds in paddy elds. To use this chemical compound as a one-shot herbicide for rice, we have developed a controlled-release formulation, pyrimisulfan-1 kg granule (containing 6.7 g a.i.). is granule formulation applied at pre-emergence to the three-leaf stage at 10 kg/ha e ciently controlled troublesome weeds, such as Echinochloa spp., perennial weeds, and sulfonylurea-resistant weeds. Furthermore, pyrimisulfan-1 kg granule exhibited consistent herbicidal e cacy under simulated over ow conditions. erefore, pyrimisulfan-1 kg granule is suitable for use as a one-shot herbicide and is an e ective tool for rice cultivation systems requiring reduced pesticide applications.

The total acreage of rice in Japan in 2009 was 1.62 million ha and most of the paddy fields are mechanically transplanted, using young seedlings grown in nursery boxes.1) It is also noteworthy that most Japanese rice farmers apply so-called one-shot herbicides, which are now essential tools for weed control in paddy fields.2) This has been made possible by the wide variety of one-shot herbicides now available on the Japanese market. While sulfonylurea (SU) herbicides are most commonly used as the active principles in the formulation of one-shot herbicides, because SU herbicides control a wide range of paddy weeds including annual broadleaves and perennial Cyperaceae and about 90% of one-shot herbicides contain 3 to 4 active ingredients. 2)We have so far developed and commercialized our original pyrimidinyl carboxy (PC) herbicides, viz. bispyribac-sodium, pyrithiobac-sodium and pyriminobac-methyl.3-5) These herbicides exhibit their activities by specifically and strongly inhibiting ALS enzyme of plants, which is involved in the biosynthesis of branched-chain amino acids in plants, such as valine, leucine and isoleucine. 6) Because mammals lack ALS enzyme, these herbicides are inherently safe for mammals and, coupled with high activity with low use rates, these PC herbicides are extensively used worldwide as environmentally friendly herbicides.In the course of our researches on PC herbicides, we confirmed that in order for a compound to exhibit high ALS inhibitory activity and high herbicidal activity, the hydrophobic group, pyrimidine ring and acidic group need be placed in a suitable spatial position linked by a suitable spacer group via a suitable linkage group. 7) Based on the findings, we have conducted extensive studies to place various hydrophobic groups and acidic groups in an appropriate position on the pyrimidine ring.PC herbicides have a carboxyl group, but due to their relatively high water solubility as a result of their acidity, PC herSynthesis and herbicidal activity of sulfonanilides having a pyrimidinyl-containing group at the 2-position A novel series of sulfonanilides having a pyrimidinyl-containing group at the 2Ј-position was prepared and their herbicidal activities against paddy weeds and selectivity against rice plants were assessed. The structure-activity relationships were probed by substitution of the sulfonyl group, bridge and benzene ring. Among the sulfonamides, difluoromethyl compound showed comparatively high activity and a broad spectrum to control weeds, including Echinochloa oryzicola. The most preferable substitution position on the benzene ring was in the 6-position and the lower alkyl group showed high herbicidal activity and a broad weed control spectrum, and among the compounds tested, the methoxymethyl group was the best. In respect of the bridge moiety, the hydroxyl group was the best. Among the compounds examined, 2Ј-[(4,6-dimethoxypyrimidin-2-yl)(hydroxy)methyl]-1,1-difluoro-6Ј-(methoxymethyl)methanesulfonanilide, applied at rates between 4 to 16 g a.i./ha, showed excelle...

We tried to develop a novel easy-to-use labor-saving formulation. And we have developed the "MAMETSUBU" formulation for paddy fields. This formulation has 3 to 8 mm diameters and disperses on the surface of water. This is a highly labor-saving formulation that can be applied from the levees by various methods without the necessity of stepping into the paddy fields. The conditions that disturb diffusion of an active ingredient in the "MAMETSUBU" formulation often changes. Therefore, spreading property of an active ingredient in the formulations was evaluated not only in small experimental fields but also in the actual paddy fields. In all of the experiments, the spreading property of the active ingredient was found sufficient enough for the formulations to be practically used. The conditions of paddy fields are usually not the same, but the "MAMETSUBU" formulation is a new formulation that can be reasonably applied.

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