Sterol biosynthesis DMIs

G1 3 C14-DeMethylation Inhibitors in sterol biosynthesis (DMI fungicides) Piperazines, pyridines, pyrimidines, imidazoles, triazoles Prochloraz, propiconazole, tebuconazole, epoxiconazole, prothioconazole Broad spectrum over 30 commercial compotmds... 

After more than 20 years of industrial research and development, strobilurins have become one of the most important classes of crop protection agents. With a distributor sales value of 1.3 billion US in 2004 [1], they currently represent approximately one-fifth of the world fungicide market (7.3 billion US in 2004 [1]). Within fungicides they rank - in commercial terms - second only to sterol biosynthesis demethylase inhibitors (DMI s), e.g. triazoles (see Chapter 17 of this book). This chapter also includes the three other Complec III inhibitors, famoxadone, fenamidone and cyazofamide, that, besides strobilurins, have achieved introduction in agricultural practice. 

Sterol Biosynthesis Inhibitors (SBIs) and Demethylation Inhibitors (DMIs)... 

In summary, prochloraz, like other azoles, is an ergosterol biosynthesis inhibitor (i.e. it is an EB1) and it does this by blocking 14-demethylation (such compounds are sometimes referred to as demethylation inhibitors, or DMIs). As is now well known, these molecules bind to the sterol binding site of the demethylase enzyme in such a way as to allow the azole to bind to an iron atom in the active site (see below). The normal physiological reaction is therefore prevented. 

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