Description
Ethrimol is a pyrimidine fungicide which is not approved for use in the UK nor the EU. It has a moderate water solubility and a low volatility. It is moderately persistent in soils and water bodies. It is moderately mobile. It demonstrates a low to moderate level of toxicity for most species. Data relating to human toxicity is scant. It las a low human toxicity via the oral route.
Chemical Properties
White crystals. Melting point: 159-160°C. Vapor pressure: 0.267×10-3 Pa at 25°C. Solubility in water: 200 mg/L at 25°C. Soluble in chloroform, trichloroethylene, strong acid and strong base solutions, slightly soluble in ethanol, practically insoluble in acetone, and relatively stable to heat.
Uses
Ethirimol is a pyrimidine based fungicide with wide applications such as controlling leaf spot of sugar beet.
Uses
Ethirimol is a systemic fungicide with both protective and curative
actions. It controls mainly powdery mildew (Erysiphe gmminis) on barley,
wheat and oats. Ethirimol can be applied as a seed dressing, as a foliar
spray or directly to the soil in the root zone.
Definition
ChEBI: An aminopyrimidine that is 2-ethylaminopyrimidin-4-one carrying butyl and methyl substituents at positions 5 and 6 respectively. A fungicide first marketed in 1970 and used as a seed treatment for diseaases such as damping-off, it is not licensed for use w
thin the European Union.
Production Methods
Ethirimol is commercially produced through a synthesis involving pyrimidine chemistry. The process typically starts with the construction of a substituted pyrimidone ring, specifically 5-butyl-2-ethylamino-6-methylpyrimidin-4-ol. This involves alkylation and amination steps using butyl and ethyl groups on a pyrimidine backbone, followed by hydroxylation at the 4-position.
Mechanism of action
Systemic, absorbed by roots and translocated. Inhibits nucleic acid synthesis (adenosine deaminase).
Metabolic pathway
Ethirimol is susceptible to photodegradation and it also degrades
extensively in soil to yield CO2 and unextractable soil-bound residues.
Metabolism in plants and animals is extensive to yield up to 16 metabolites.
Elimination in animals was rapid following oral dosing. Metabolism
in soil, plants and animals follows common pathways which include
N-dealkylation, hydroxylation of the butyl group and conjugation.
Degradation
Ethirimol (1) is stable to hydrolytic degradation in buffered solutions
at pH 5, 7 and 9 at 22°C. It degraded under aqueous photolysis test
conditions with a half-life (DT50) of ca. 3 weeks. The primary photolytic
degradation reactions include the opening of the pyrimidine ring to yield
ethylguanidine (2), urea (3) and 4-butylpyrazolidine-3,5-dione (4) (Cavell
et al., 1974c).
Pesticide Type
Fungicide; Metabolite
