Chemical Properties
Pentoxystrobin pure product is white powdery solid, melting point 60.3~61℃. Boiling point:>360°C, 99.2°C (1.9 Pa). Vapor pressure:0.17mPa(20℃),0.37mPa(25℃). Relative density 1.3. partition coefficient Kow lgP= 3.72( pH 5.7,20°C). Henry's constant 6.6×10-4Pa-m3/mol (calculated). Solubility in water 73 mg/L (25°C). Solubility in other solvents (25°C, g/L): ethanol 730, acetone 770, n-octanol 400, toluene 610, n-hexane 24. pH 1~13 hydrolytically stable; stable when heated to 350°C.
Uses
Penconazole is an conazole based fungicide that works by inhibiting cell membrane ergosterol biosynthesis, thus stopping the development of fungi.
Uses
Penconazole is used for the control of powdery mildew,
pome fruit scab and other pathogenic Ascomycetes, Basidiomycetes and
Deuteromycetes on vines, cucurbits, pome fruit, stone fruit, ornamentals,
hops, tobacco and vegetables.
Definition
ChEBI: 1-[2-(2,4-dichlorophenyl)pentyl]1,2,4-triazole is a member of the classof triazoles that is 1,2,4-triazole substituted at position 1 by a 2-(2,4-dichlorophenyl)pentyl group. It is a dichlorobenzene and a member of triazoles.
Production Methods
Penconazole is synthesised through a multi-step chemical process starting with 2-(2,4-dichlorophenyl)pentanol. In one method, the compound is first brominated to form a reactive bromide intermediate. The bromide then undergoes a condensation reaction with 1,2,4-triazole under alkaline conditions, typically using sodium hydroxide, to form the penconazole molecule. An alternative synthesis involves esterifying the starting alcohol with concentrated sulphuric acid and using 4-methyl-2-pentanone as a water-carrying agent, followed by reaction with triazole. The final product is purified through washing, phase separation, and crystallisation, yielding high-purity penconazole.
Agricultural Uses
Fungicide: Penconazole is a systemic fungicide used to control
powdery mildew. It is used on apples and grapes and
other fruits, hops, tobacco, ornamentals and on vegetables.
Not currently registered in the U.S. Reported to be used in
most European countries. Currently, there are more than
30 global suppliers.
Trade name
AWARD®; CGA-71818®; ONMEX®;
TOPAS®; TOPAS-C®; TOPAS-MZ®; TOPAZ®;
TOPAZE®; TOPAZE-C®; TOPENCO 100EC®
Mechanism of action
Systemic with curative and protective action, acts by interfering with ergosterol biosynthesis
Safety Profile
Moderately toxic by ingestion and skin contact. When heated to decomposition it emits toxic vapors of NOx and Clí.
Metabolic pathway
Penconazole is metabolised in plants by hydroxylation of the propyl side
chain and conjugation or metabolism to triazolylalanine and triazolylacetic
acid. It is quite persistent in soils but degradation by sunlight
requires only a few days. It is eliminated rapidly from mammals.
Degradation
Penconazole (1) is stable to hydrolysis at pH 1-13 and at temperatures up
to 350 °C. It is degraded in sunlight with a DT50 of 4 days in natural sunlight.
Its photochemical reactions have been studied. On irradiation with
light of wavelengths greater than 280 nm (high-pressure mercury lamp
with filter), the major reaction was the formation of a cyclised product (2)
(Scheme 1). Irradiation under the same conditions in isopropanol gave
mainly 2 and 3 (a dechlorinated product). After 8 hours, yields were 29.8%
of 2 and 12.3% of 3 respectively. The product 3 alone photodegraded
only slowly but 2 was completely photolysed within 3 hours to further
products, indicating its role as an intermediate in the photolytic pathways
(Schwack and Hartmann, 1992, 1994). In the presence of isopropanol,
photodehalogenation of 3 to 4 competed with substitution of a
solvent molecule to give a low yield (
