Introduced in 1955, fenaminosulf (1; Lesan; Dexon)
was one of the first selective, systemic fungicides.
It is active against Phycomycetes such as Pythium,
Phytophthora, and Aphanomyces but has little or no
effect on higher fungi belonging to the Ascomycetes or
Basidiomycetes. Fenaminosulf has a relatively high water
solubility (20,000 mgL-1), a feature often associated
with fungicides that specifically inhibit Oomycetes (3).
Another important physicochemical property is photolytic
instability, one of the reasons that fenaminosulf was
developed as a seed dressing and soil fungicide (4).
As a consequence of acute toxicity , limited
spectrum, and photo-instability, the use of fenaminosulf
decreased (4), and it is now listed in The Pesticide
Manual (5) among products that have been superseded.
Although no longer used, it is included here for
completeness, being the only example of a commercial
fungicide that acts on complex I.
During its period of use, fenaminosulf, as wettable powder
(WP), dust, or granular formulations, was employed
as a seed dressing and soil-applied fungicide to control
damping off and foot/root rots. Fenaminosulf-based products
were used on a range of plants including vegetables,
field crops, ornamentals, and turf.
Used in biological and pharmacological studies including:• ;Cloning and characterization of GABA transporter1• ;Activity of anti-RSV carbonucleosides2• ;Inhibition by fungicides of urea hydrolysis and nitrification of urea nitrogen in soil3
ChEBI: Fenaminosulf is an organic molecular entity.
The commercial production of fenaminosulf follows a concise two-step diazo coupling process. First, N,N-dimethylaniline is diazotised by adding sodium nitrite to a cold solution of the amine in dilute acid forming the diazonium chloride salt in situ under controlled pH. This diazonium salt is then coupled with sulphite ions (from sodium sulphite or bisulphite) in a buffered aqueous medium, where the electrophilic diazonium attacks the sulphite to yield the diazosulfonate anion, followed by neutralisation with sodium carbonate to precipitate or crystallise fenaminosulf.
Yellow-brown crystals or brown powder.
Dust may form an explosive mixture in air. Water soluble.
Aqueous solutions are sensitive to exposure to light.
Flash point data are not available for Fenaminosulf. Fenaminosulf is probably combustible.
Interferes with NADH-ubiquinone reductase (complex I).
Poison by ingestion,
intravenous, and intraperitoneal routes.
Experimental teratogenic effects. Human
mutation data reported. Questionable
carcinogen, A fungicide. When heated to
decomposition it emits very toxic fumes of
NOx, Na2O, and SOx
