Fenamidone (13; RPA 407213; (S)-5-methyl-2-methylthio-
5-phenyl-3-phenylamino-3,4-dihydroimidazol-4-one) is a complex III inhibitor
that does not derive from the strobilurins but rather
belongs to the imidazolinone chemical class. Fenamidone is a white woolly powder, with the
following characteristics: mp = 137 ?C; water solubility =
7.8 mg/L; logP = 2.8, and vp = 3.4×10?7 Pa. It was
first described by Mercer et al. (39) in 1998. Only the
S-enantiomer shows antifungal activity, thus offering a
reduction in application rates over the racemic mixture.
ChEBI: A member of the class of imidazolones that is 3,5-dihydroimidazol-4-one substituted at position 2 by a methylthiogroup, at position 3 by an anilino group and at position 5 by phenyl and methyl groups (the S-enantiomer). A fungicide effecti
e against Oomycete diseases such as downy mildew and certain leaf spot diseases.
Moderately toxic by ingestion and skin contact. Low toxicity by inhalation.
Fenamidone has an acute oral LD50 > 5,000 and an
acute dermal LD50 > 2,000 mg/kg in rats. Fenamidone is
not a skin or eye irritant, is negative in the Ames test, and
is nonteratogenic. It shows low toxicity to birds in acute
and dietary studies but has a 96-h fish LC50 of 0.74 mg/L.
