Stephan Trah

Synthesis and fungicidal activity of tubulin polymerisation promoters. Part 2: Pyridazines

Special tetrasubstituted pyridazines are potent fungicides by promoting the tubulin polymerisation, hereby disrupting the microtubule dynamics in the fungus. They are monocyclic analogs of similar substituted triazolopyrimidines and pyridopyrazines with the same mode of action. The fungicidal activity of these pyridazines was evaluated against the plant pathogens Botrytis cinerea (grey mould), Mycosphaerella graminicola (wheat leaf blotch) and Alternaria solani (potato and tomato early blight). Structure-activity relationship studies revealed the importance of a methyl and a chlorine substituent next to both ring nitrogen atoms and two aryl or heteroaryl groups in the other two pyridazine positions.

Synthesis and fungicidal activity of quinolin-6-yloxyacetamides, a novel class of tubulin polymerization inhibitors

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.

Bicyclic heterocyclic anthranilic diamides as ryanodine receptor modulators with insecticidal activity.

The diamide insecticides act on the ryanodine receptor (RyR). The synthesis of various bicyclic anthranilic derivatives is reported. Their activity against the insect ryanodine receptor (RyR) and their insecticidal activity in the greenhouse is presented, as well as structure activity relationship considerations.

The Significance of Organosulfur Compounds in Crop Protection: Current Examples from Fungicide Research

GRAPHICAL ABSTRACT Abstract Approximately 30% of todays 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.