Oxycarboxin is an organic chemical used in agriculture to protect crops from fungal diseases. It was first marketed by Uniroyal in 1969 under the brand name Plantvax. The compound is a benzanilide analog which combines a heterocyclic acid with aniline to give an inhibitor of succinate dehydrogenase (SDHI).
Synthesis
Oxyxarboxin was first made by the
oxidation of
carboxin, as disclosed in patents filed by Uniroyal.
Ethyl 2-chloroacetoacetate is treated with 2-mercaptoethanol and base, followed by cyclisation and water removal under acidic conditions. The resultant ethyl ester of the 1,4-oxathiine
heterocycle is then formed into an
amide with aniline using standard conditions via the
carboxylic acid and acid chloride. This gives carboxin in high overall yield.
The synthesis is completed by treatment with 30% hydrogen peroxide in
acetic acid.
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Mechanism of action
Carboxin and oxycarboxin act by inhibition of succinate dehydrogenase (SDHI):
Uses
Oxycarboxin is used to control rust diseases (e.g. soybean rust) at an application rate of 200–400 g/ha.
History
Oxycarboxin has been commercially available since 1969, when it was introduced under the brand name Plantvax.
