Fungicides tridemorph

Although termed "SI" or "EBI" compounds, the latter referring to ergosterol biosythesis inhibitors, these compounds do not all inhibit ergosterol biosynthesis at the same metabolic site (Fig. 2). For instance, the fungicide tridemorph, unlike most EBI compounds, does not inhibit demethylation at C-14 but rather it apparently prevents the A A isomerization resulting in the accumulation of A containing sterols in treated cells (3). 

Figure 2.27 The fungicides tridemorph 99 (n = 12 is the major component, but n = 10, 11, and 13 are present in minor amounts) and fenpropimorph 100 are picomolar a, receptor ligands which still await their optimization to drug candidates.

Inhibitors of Sterol A —> A Isomerization. Initial mode of action studies indicated that the morpholine fungicide tridemorph blocked sterol A —> A isomerization (21-23) or sterol A reduction (24). Subsequently, it was shown that morpholines may block both reactions or only the former, depending on the organism and morpholine derivative involved (21). Detailed mode of action... 

Propose a synthesis for the systemic agricultural fungicide tridemorph from dodecanoic acid (lauric acid), propene, and a one-carbon building block. How many stereoisomers are possible for tridemorph ... 

Morpholines such as tridemorph (9.112) attack sterol biosynthesis via A -reductase enzyme inhibition and are valuable agricultural fungicides. 

A8,7 Isomerase and A14 Reductase. Before the appearance of resistance to azole fungicides in cereal powdery mildew the A8,7 isomerase and A14 reductase inhibitors were of minor importance because of their limited spectrum. Only seven examples of this group have shown commercial potential fenpropimorph, fenpropidin, tridemorph, dode-morph, aldimorph, piperalin, the first member of the series, introduced by Eli Lilley (now Dow Agrosciences) in 1960, and spiroxamine, the latest addition (Figure 4.5). 

Selectivity is brilliantly displayed by a multiplicity of compounds developed for the control of powdery mildews. For 148 years from 1803 until 1951 sulfur was the only significant fungicide for powdery mildew. In 1949 a new fungicide appeared with the publication of 6-(1-methylheptyl)-2,4 dinitro-phenyl crotonate (8). Two years later Yarwood reported (9) its anti-powdery mildew properties. It went on to worldwide usage and thus stimulated a vast search for others. Now we have many effective compounds, including benomyl, binapacryl, dodemorph, folpet, parinol, piperalin, pyrazophos, thiophanate, tridemorph, triforine, and dthers. 

Although one report identified field Isolates of E. gramlnis f.sp. horde resistant to tridemorph (22) no practical case of resistance to morpholine fungicides has emerged in any disease. This is remarkable given the specificity in their mode of action, and their continuous and increasing use against cereal mildews since tridemorph was introduced in 1970. 

Calixin . [BASF AG] Tridemorph cmnpds. systemic fungicide. 

Cosmic FL. [BASF AG] Maneb, tridemorph, carbendazim broad spectrum cer fungicide. 

The first SBI fungicides to be introduced as agricultural fungicides were, chemically, morpholines such as dodemorph and tridemorph, which had already entered the market at the end of the 1960s (Table 17.21). Whereas dodemorph was mainly developed in ornamentals, tridemorph gained importance in cereal crops and bananas [97]. 

Fenbuconazole Fenfuram Fenpropimorph Flutriafol Fosetyl-aluminum 8-Hydroxyquinoline sulfate Imazalil Oxycarboxin Tebuconazole Thiophanate Triadimenol Tridemorph fungicide, systemic agric. 

Maize a7-SR was also shown to be inhibited by ammonium-ion fungicides such as tridemorph (1). The data is in accordance with the abovementioned cationic mechanism. Moreover it indicates that plant A -SR might be a tai get of such fungicides. 

Tridemorph is a broad spectrum microbicide which was developed by BASF 1969 as a systematizing fungicide for plant protection. It may also be used in wood preservatives. At applieation rates of <100mg/l it has been found to be active against wood colouring and wood destroying fungi. 

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