Natural products fungicides

The bactetiostatic and fungicidal properties of bode acid have led to its use as a preservative in natural products such as lumber, mbber latex emulsions, leather, and starch products. 

It is interesting that a new group of fungicides based on the natural products from the fungus Strobilurus tenacellus also inhibit mitochondrial respiration at the site of complex III (bei-complex) of the respiratory chain (see Chapter 4). Recently synthesised compounds from within this class are showing interesting insecticidal effects. 

DISCOVERY AND EVALUATION OF NATURAL PRODUCT-BASED FUNGICIDES FOR DISEASE CONTROL OF SMALL FRUITS... 

P-Methoxyacrylates. This is an important class of commercial fungicides based on a group of natural products, the strobilurins (see Fig. 10), such as strobilurin A and oudemansin A. Strobilurins act by inhibition of mitochondrial respiration. In 1996, the first representatives of this class of fungicide were launched, including azoxystrobin [52], In 1999, the first fluorine-containing strobilurin, trifloxystrobin (Flint ) [53], was launched by Syngenta and later acquired by Bayer for 760 million. 

Fig. 10. Evolution of strobilurin fungicides from their natural products precursors.

Barrett and Lebold used the Brown asymmetric crotylation to prepare the homoallyhc alcohol 22 in the total synthesis of nikkomycin B 21, a natural product that exhibits fungicidal, insecticidal, and acaricidal activities14 (Scheme 3.1k). 

The phenylpyrrole class of fungicides includes the conq>ounds fenpiclonil and fludioxo-nil. These chemistries have been developed fix>m the natural product lead molecule pyr-rolnitrin produced by Pseudomonas pyrrocinia (Fig. 3). The photoinstability of pyrrol-nitrin was overcome in the synthetic analogs and these compounds are now used for the control of Botrytis cinerea, Monilinia, and Sclerotinia spp. [12]. 

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