Shizuya Tanaka

In vitro mode of action of N-Phenylimide photobleaching herbicides

Abstract The effect of N-Phenylimide photobleaching herbicides on in vitro synthesis of protoporphyrin was examined. The N-phenylimide photobleaching herbicide S-23142 [N-(4-chloro-2-fluoro-5-propargyloxyphenyl)-3,4,5,6-tetrahydrophthalimide] inhibited the Mg-protoporphyrin IX synthesis of intact plastids by 50% at 10−10 M. Protoporphyrin IX synthesizing activity was solubilized from plastid membranes by n-dodecyl β- d -maltoside, and the solubilized activity was inhibited by several photobleaching herbicides. In vitro binding of N-phenylimide photobleaching herbicide, S-23121 [N-[4-chloro-2-fluoro-5-[(1-methyl-2-propynyl)oxyl]phenyl]-3,4,5,6-tetrahydrophthalimide], to a solubilized plastid fraction was examined. A good correlation between protoporphyrin IX synthesizing activity and [14C]S-23121 specific binding was observed. Binding site affinity (Kd) was 8.9 – 9.8 nM. The binding was displaced by a diphenylether photobleaching herbicide, acifluorfenethyl, and another N-phenylimide, S-23142, but not by a photosystem II electron transport inhibitor, DCMU. Bound [14C]S-23121 was dissociated by an excess of cold S-23121, which indicated the reversible binding of S-23121.

Decomposition analyses of the intermolecular interaction energies in two p-p stacking complexes: quinhydrone and N,N,N′, N′ -tetramethyl- p -diaminobenzene-chloranil complex

Although there is a similarity in the orbital interaction scheme between quinhydrone and N,N,N′,N′‐tetramethyl‐p‐diaminobenzene‐chloranil complex, the stacking conformations are different from each other. The former prefers the half‐stacked conformation, whereas the latter prefers the completely stacked conformation. We have done ab initio molecular orbital calculations and decomposition analyses of the intermolecular interaction energies to clarify the origin of the different stacking conformations. It was concluded that the main origin is the difference in the steric part of the interaction energies.

STRUCTURE-ACTIVITY RELATIONSHIPS OF A NEW FUNGICIDE S-3308 AND ITS DERIVATIVES

A new triazole fungicide S-3308 was effective for control of powdery mildews, rusts, scabs and other phytopathoqenic diseases. It showed inhibition of ergosterol biosynthesis in fungi and PGR activity on certain plants. Structure-activity study (substituent on phenyl ring, imidazole or triazoler configuration about double bond, ketone or alcohol structure, alkyl moiety and optical isomers) revealed that not only partial structures but also steric structures were important for high activities.

Fungicidal Activities of 1, 1-Diisopropyl-2-(3-pyridyl)-3-p-ethoxy-phenylguanidine and Its Analogs

Structure-activity relationships were studied on 25 analogs of 3-pyridylguanidines toward powdeiy mildew. Only the di-sec-alkyl analogs were active among the 1-alkyl or 1,1-dialkyl-2-(3-pyridyl)-3-p-ethoxyphenyIguanidines on available data. The activity was linearly correlated with Hammett’s σ constant of the substituents on the phenyl group, among which cyano, benzyloxy, alkoxy and diethylamino groups showed higher activity than chloro, nitro, methyl, bromo and phenyl groups. Fungitoxic spectrum and other fungicidal natures were also shown and compared with those of S–1358 and its derivatives.

Synthesis and Fungicidal Activity of 1-(α-tert-Butylcinnamoyl)imidazoles

Several 1-(α-tert-butylcinnamoyl)imidazoles were prepared to examine their fungicidal activity. The (Z)-4-chlorocinnamoyl derivative was prepared from (anti)-2-tert-butyl-3-(4-chlorophenyl)-3-hydroxypropanoic acid by treating with 1,1′-carbonyldiimidazole and a subsequent β-elimination reaction at an elevated temperature. The (Z)-isomer of the 4-chlorocinnamoyl derivative showed good fungicidal activity against Erysiphe graminis and Botrytis cinerea in pot tests, whereas the corresponding (E)-isomer derived from the (Z)-isomer through photoisomerization was much less active.

Invention and Industrialization of New Optically Active Triazolyl Plant Growth Regulator and Fungicide.

著者らが先に見出した殺菌剤ブチオオートの構造活性相関や作用機作研究の結果を活用した分子設計により,強い植物生畏調節活性と殺菌活性を餅せ持つ新規な2-(トリアゾリル)アリルアルコール系化合物を得た.本化合物には幾何異性体と光学異性体が存在する。E異性体の活性はZ異性体に比して大幅に向上すること,また,檀物生長鯛節活性はS体に,殺菌活性はR体に集中していることを明らかにし,二つの薬効の分離に成功した,前者はジべレリンの,後者はエルゴステロールの生合成を選択的に阻害する。製造法では,E/Z異性化技術と分離技術を組み合わせた異性化晶析法を開発し,E体を選択的に合成する簡便な工業的製造法を確立した。また,新規な不斉修飾剤であるアミノアルコールと水素化アルミニウムリチウムを用いる。高選択的不斉還元法により光学活性E型2-(トリアゾリル)アリルアルコールの合成に成功,さらに,ノルエフェドリン系アミノアルコールで不斉修飾した水素化ホウ素ナトリウムを用いることによって,操作性・安全性に優れる工業的不斉還元法を開発し,植物生長調節剤と殺菌剤の作物保護剤2剤を同時に上市すると共に,薬量の一層の低滅化を達成した。

The relationship between the bleaching pattern on radish cotyledons and hydrophobicity of herbicidal 3-phenoxybenzamides

3-フェノキシベンズアミド類縁体をダイコンの種子に浸漬処理すると, 展開した子葉は化合物により異なる白化状態を示した. 子葉の白化状態は2枚の子葉の裏表, 計4面での白化の程度に基づいて三つのパターン (A, B, C) に分類することができた. 化合物の疎水性と白化パターンとの関係を調べると, 疎水性の比較的小さい化合物 (log KOW2.57～3.89) では2枚の子葉とも全面が白化した (パターンA). 一方, より疎水性の大きい化合物では部分的に白化しただけであり, 1枚の子葉が完全に白化し, もう1枚は周辺だけが白化したもの (パターンB, log KOW4.35, 4.43) と, 2枚の子葉とも周辺のみ白化したもの (パターンC, log KOW4.78, 5.01) に分かれた. 子葉の白化パターンの変化は化合物の疎水性の差に基づいた移行性の違いによって起こっていることが示唆された.