Other Leads in the Area of Complex I Inhibitors

There are only a few leads in the fungicide area worth mentioning in this chapter. Phenoxan (18) [45], a secondary metabolite isolated from Polyganium sp. strain PI VO 19 with an oxazole-y-pyrone structure is discussed as a first example (Fig. 

Whereas fenazaquin (1) is a well-known complex I inhibitor, the primary mode of action of quinoxyfen (21) is, as yet, unknown. Although the lepidine compound 22 (Fig. 13.5.8) shows sub-micromolar activity level Ustilago maydis -IC50 0.73 pmol) in the biochemical complex I assay, the activity level in glasshouse tests is not satisfying at all. 

The chances of finding lepidine derivatives of sufficient biological activity in agrorelevant disease complexes are rather low [47]. 

3 In 2003 SDS Biotech acquired the agrochemical fungicide business from Ube Industries including diflumetorim. 

Walter, topic presented in part at the Fourth Conference of Iminium Salts, Stimpfach-Rechenberg (Germany), September 1999. 

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