Pesticide discovery

Discovery. The traditional approach to new pesticide discovery was to make iatuitive changes ia the substitueats oa a promising primary chemical stmcture. Initially, materials from any source were subjected to screening for biological activity as iasecticides, herbicides, or fungicides. 

L.G. Copping, Aspects of Pesticide Discovery , in Recent Developments in the Field of Pesticides and their Application to Pest Control , ed. K. Holly, L.G. Copping and G.T. Brooks, United Nations Industrial Development Organisation, Vienna, 1990, pp. 16-26. 

Evaluation of natural compounds has been a relatively small part of the herbicide discovery effort of most companies involved in pesticide discovery. In some cases, the company has put significant effort into isolation of phytotoxic compounds from various organisms as part of a bioprospecting effort. This activity has led to several commercial herbicides, including glufosinate, bialaphos, the triketones, and pelargonic acid. 

The reasons why natural products have not been an area of focus for pesticide company discovery efforts are several. They include the relatively high cost of bioassay-directed isolation, the probability of rediscovery, and the often prohibitively complex structure of the active molecule. Furthermore, the strategies for discovery of natural product-based pesticide discovery are different from those for synthetic compounds, requiring a somewhat different laboratory infrastructure. New methods, including semi-automated bioassays, automated chemical extraction and analysis, and molecular biology methods to... 

A panel discussion was convened at the end of the symposium to summarize impressions and highlight problems and approaches to the integration of basic knowledge of target sites and responses into a more rational approach to pesticide discovery. The results of this discussion are presented here, and we feel that they will be an illuminating record of the current state of the art. 

In writing this review I had in mind the need to demonstrate how the rational approach to pesticide discovery could be facilitated by recent discoveries in basic research. Although I am unable at this time to offer chemical structures for industrial exploitation I am confident that there is much to be gained commercially by considering non-competitive antagonists of glutamate receptors as lead structures. 

I have worked for nearly half a century as a synthetic chemist in the field of natural products chemistry relating to pesticide science. This review comprises four topics (1) pesticides and our daily life, (2) contributions to pesticide discovery by Japanese scientists, (3) my lab s past natural product syntheses in relation to pesticide science, and (4) our past efforts in pheromone synthesis. In other words. Sections (1) and (2) are the general treatise on the historical description of human endeavor for searching environmentally benign methods for pest control, while Sections (3) and (4) are reviews of works undertaken in my own laboratory. 

Figure 2. japan s contribution in pesticide discovery and manufacturing. 

After the discovery that ortho-biphenyl substituted hydrazide compounds [5] had acaricidal activity in the pesticide discovery screen (Table 30.2.3) several hundred - structurally diverse - biphenyl-substituted carbazate analogs were synthesized, and, in an optimization process using a bioassay with the two spotted spider mite (Tetranychus urticae Koch), isopropyl-2-(4-methoxy[l,l -biphenyl]-3-yl) hydrazine carboxylate (bifenazate) [3, 8] was identified as the most advantageous compound. 

The Application of Quantitative Design Strat es in Pesticide Discovery... 

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