Oxycarboxin is an organic chemical used in agriculture to protect crops from fungal diseases.

The compound is an anilide which combines a heterocyclic acid with aniline to give an inhibitor of succinate dehydrogenase (SDHI).

[1][2][3] Oxyxarboxin was first made by the oxidation of carboxin, as disclosed in patents filed by Uniroyal.

[4] Ethyl 2-chloroacetoacetate is treated with 2-mercaptoethanol and base, followed by cyclisation and water removal under acidic conditions.

[4] Carboxin and oxycarboxin act by inhibition of succinate dehydrogenase (SDHI):[6] they bind to the quinone reduction site of the enzyme complex, preventing ubiquinone from doing so.