P-Methoxyacrylates

Azoxystrobin (P-methoxyacrylate) is one of 1400 synthesized from the lead compound, strobilurin A. 

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. 

Figure 2. Natural Fungicidal Derivatives of p-Methoxyacrylic Acid...

Haliangicin 346, a novel p-methoxyacrylate antibiotic with a conjugated tetraene moiety, was isolated from the culture broth of marine myxobacterium, Haliangium luteum The strain was isolated from a seaweed sample collected at a sandy beach in the Miura Peninsula, Kanagawa, Japan. In studies, haliangicin inhibited the growth of a wide... 

P-Methoxyacrylate, srr Azoxystrobin 2-Methoxyhydroquinorie, 110 2-(3 -Methoxyphenyl)-n pbitbyridinOne, 82 IS Methyipuupehenol, 250 Mevastatin, plant-derived sources of, 41 Mi conur iepidoia DC, 56 Miltirone... 

The convergent total synthesis of Myxothiazoles involves a Wittig reaction as the last step. In this procedure, P-methoxyacrylic aldehyde derivatives were treated with a bisthiazole-based phosphonium salt in the presence of a base (Scheme 89). ... 

The development of a new class of synthetic agricultural fungicides based on the naturally occurring P-methoxyacrylates is described. A consideration of structure-activity relationships and key physical properties has led to a series of tricyclic compounds which still incorporate the P-methoxyacrylate toxophore. The best examples of these compounds combine high levels and a broad spectrum of stemic fungicidal activity with good crop safety. 

Five standard approaches to the generation of new areas for agrochemical (and pharmaceutical) research are commonly cited random screening speculative nthesis imitative ("me-too") chemistry biorational design and finally the exploitation of natural products (7). Although this last approach has found much commercial success in the development of novel insecticides (for example the pyrethroids), there are still relatively few examples of herbicides and fungicides which have been discovered in this way. This account describes the development of a new class of fungicides derived from the strobilurin family of natural products and related compounds, all of which are derivatives of P-methoxyacrylic acid. 

Synthesis of Tetronic Acids. —Lithiation of methyl p-methoxyacrylate and reaction with the dienone (198) leads to the tetronate (199), in one step. Further lithiation of (199), followed by acylation, is then shown to produce the enol ether isomer (200) of natural aspertetronin A (Scheme 108). In similar studies. 

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