Description
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.
Definition
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.
Hazard
Moderately toxic by ingestion and skin contact. Low toxicity by inhalation.
Toxicity evaluation
Fenamidone has an acute oral LD
50 > 5,000 and an
acute dermal LD
50 > 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.
