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A novel class of experimental fungicides has been discovered, which consists of special N-thiazol-4-yl-salicylamides. They originated from amide reversion of lead structures from the ...patent literature and are highly active against important phytopathogens, such as Phytophthora infestans (potato and tomato late blight), Plasmopara viticola (grapevine downy mildew) and Pythium ultimum (damping-off disease). Structure–activity relationship studies revealed the importance of a phenolic or enolic hydroxy function in the β-position of a carboxamide. An efficient synthesis route has been worked out, which for the first time employs the carbonyldiimidazole-mediated Lossen rearrangement in the field of thiazole carboxylic acids.
Mandipropamid is a highly efficient new fungicide against the agronomically important oomycetes diseases
Phytophthora infestans (potato and tomato late blight) and
Plasmopara viticola (grape downy ...mildew).
Isocyanide-based multicomponent reactions of the Ugi- and Passerini-type have been valuable tools for the rapid exploration of the novel fungicidal compound classes of phenylglycinamides and mandelamides. Mandipropamid (
6), which was discovered during this derivatisation, displays excellent activity against the economically important phytopathogens
Phytophthora infestans (potato and tomato late blight) and
Plasmopara viticola (grape downy mildew).
Derivatives of the new class of 3-hydroxy-4-phenyl-5-oxo-pyrazolines were optimized towards both herbicidal activity on key annual grass weed species and selectivity in small grain cereal crops. The ...generic structure can be separated into three parts for the analysis of the structure–activity relationships, namely the aryl, the dione with its prodrug forms and the hydrazine moiety. Each area appears to play distinct and different roles in overall expression of biological performance which is further beneficially influenced by adjuvant response and safener action. Pinoxaden
6, a novel graminicide for use in wheat and barley incorporating a 1,4,5oxadiazepane ring, eventually emerged as a development candidate from the discovery and optimization process.
Approximately 30% of today's agrochemicals contain at least one sulfur atom. This review article highlights the most important reasons for the fundamental role of sulfur functions in crop protection, ...such as the occurrence of sulfur in agrochemical pharmacophores, the application of sulfur-containing natural products as lead compounds, the role of sulfur in procidal action, fine-tuning of physico-chemical properties and patent breaking as well as the advantage of sulfur-containing heterocycles compared to their nonsulfur ring isosteres. Case studies from three different mode of action classes give proof, how state-of-the-art organosulfur chemistry enables the synthesis and influences the structure-activity relationships of fungicidally active compounds in the classes of Succinate dehydrogenase inhibitors, tubulin polymerization inhibitors and Cellulose synthase inhibitors.
The natural product Rocaglamide (1), isolated from the tree Aglaia elliptifolia, is a compelling but also challenging lead structure for crop protection. In laboratory assays, the natural product ...shows highly interesting insecticidal activity against chewing pests and beetles, but also phytotoxicity on some crop plants. Multi-step syntheses with control of stereochemistry were required to probe the structure-activity relationship (SAR), and seek simplified analogues. After a significant research effort, just two areas of the molecule were identified which allow modification whilst maintaining activity, as will be highlighted in this paper.
The efficacy of all major insecticide classes continues to be eroded by the development of resistance mediated, in part, by selection of alleles encoding insecticide insensitive target proteins. The ...discovery of new insecticide classes acting at novel protein binding sites is therefore important for the continued protection of the food supply from insect predators, and of human and animal health from insect borne disease. Here we describe a novel class of insecticides (Spiroindolines) encompassing molecules that combine excellent activity against major agricultural pest species with low mammalian toxicity. We confidently assign the vesicular acetylcholine transporter as the molecular target of Spiroindolines through the combination of molecular genetics in model organisms with a pharmacological approach in insect tissues. The vesicular acetylcholine transporter can now be added to the list of validated insecticide targets in the acetylcholine signalling pathway and we anticipate that this will lead to the discovery of novel molecules useful in sustaining agriculture. In addition to their potential as insecticides and nematocides, Spiroindolines represent the only other class of chemical ligands for the vesicular acetylcholine transporter since those based on the discovery of vesamicol over 40 years ago, and as such, have potential to provide more selective tools for PET imaging in the diagnosis of neurodegenerative disease. They also provide novel biochemical tools for studies of the function of this protein family.
An extensive screening of both homogeneous and heterogeneous catalysts was carried out for the enantioselective hydrogenation of p‐chlorophenylglyoxylic acid derivatives. For p‐chlorophenylglyoxylic ...amides only homogeneous Rh‐diphosphine complexes gave satisfactory results, ees up to 87% were observed for the cy‐oxo‐pronop ligand. For methyl p‐chlorophenylglyoxylate both a homogeneous as well as a heterogeneous catalyst performed with ees >90%. A Pt catalyst modified with cinchona derivatives achieved 93% ee for the (R)‐ and 87% ee for the (S)‐methyl p‐chloromandelate. A Ru‐MeObiphep catalyst also reached 93% ee with TONs up to 4000 and TOFs up to 210 h−1. For all catalytic systems the effects of the metal, the nature of the chiral auxiliary and the solvent as well as of the reaction conditions were investigated. The homogeneous process was scaled up to the kg scale and the enantiomeric purity of the product was enhanced to >99% ee by two recrystallizations of the free p‐chlorophenylmandelic acid.
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Novel imidazole-based ketene dithioacetals show impressive in planta activity against the economically important plant pathogens Alternaria solani, Botryotinia fuckeliana, Erysiphe ...necator and Zymoseptoria tritici. Especially derivatives of the topical antifungal lanoconazole, which bear an alkynyloxy or a heteroaryl group in the para-position of the phenyl ring, exhibit excellent control of the mentioned phytopathogens. These compounds inhibit 14α -demethylase in the sterol biosynthesis pathway of the fungi. Synthesis routes starting from either benzaldehydes or acetophenones as well as structure-activity relationships are discussed in detail.
A novel class of experimental fungicides has been discovered, which consists of special quinolin-6-yloxyacetamides. They are highly active against important phytopathogens, such as Phytophthora ...infestans (potato and tomato late blight), Mycosphaerella graminicola (wheat leaf blotch) and Uncinula necator (grape powdery mildew). Their fungicidal activity is due to their ability to inhibit fungal tubulin polymerization, leading to microtubule destabilization. An efficient synthesis route has been worked out, which allows the diverse substitution of four identified key positions across the molecular scaffold.
Ei-ichi Negishi will remain known for pioneering and promoting the development of transition-metal catalyzed reactions in organic synthesis as well as fostering excellence and critical thinking among ...his collaborators. During his lifetime, with his wife Sumire by his side, he conquered many continents: in the chemical world, his name is associated with cross-coupling, cascade reactions, carbopalladation, zirconocene chemistry, and asymmetric synthesis; in life, we remember him as a kind, generous, and approachable individual that mastered golfing, singing, and skiing, among other things.
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