Meptyldinocap

Description

Meptyldinocap is a protectant, curative and eradicant fungicide. It has a low aqueous solubility, it is volatile and, based on its chemical properties, is unlikely to leach to groundwater. It is not persistent in soil and will usually degrade in water systems quickly. It is moderately toxic to mammals and bioaccumulation may be a concern. Whilst it is not highly toxic to birds, it is more toxic to many aquatic species including fish and algae.

Uses

Dinocap is a contact fungicide which provides both protective and curative activities against powdery mildews, fruit rots, stem rots, leaf spots, brown rots, etc., in a wide range of crops including pome fruits, stone fruits, citrus, vines, hops, ornamentals and berries.

Definition

ChEBI: 2,4-dinitro-6-(octan-2-yl)phenyl (E)-but-2-enoate is an enoate ester obtained by formal condensation of the carboxy group of 3-methylacrylic acid with the phenolic hydroxy group of 2,4-dinitro-6-(octan-2-yl)phenol. It is a C-nitro compound and an enoate ester.

Production Methods

The industrial synthesis of meptyldinocap begins with the preparation of the dinitrophenol core, typically derived from 2,4-dinitrophenol. This compound is then alkylated with 1-methylheptyl bromide to introduce the hydrophobic side chain, enhancing lipophilicity and plant surface adhesion. The resulting intermediate undergoes esterification with crotonic acid (2-butenoic acid) under acidic conditions, forming the final ester linkage. The reaction is carried out in organic solvents like toluene or acetonitrile, with temperature and pH carefully controlled to ensure high yield and minimal by-product formation.

Mechanism of action

Protectant, curative and eradicant activity by inhibiting spore germination. Uncoupler of oxidative phosphorylation

Metabolic pathway

Dinocap is a mixture 2,4- and 2,6-dinitro isomers of octylphenyl crotonate. Limited data are available in the open literature. Information presented in this summary is abstracted from the data evaluation published by the Pesticide Safety Directorate (PSD). Degradation and metabolism studies were conducted mainly with the 2,4-dinitro isomer. Hydrolytic cleavage of the crotonate to yield the corresponding phenol is the primary pathway in soil, plants and animals. β-Hydroxylation and/or carboxylation of the octyl moiety is a minor pathway in animals (Scheme 1).

Degradation

The hydrolytic degradation of dinocap [1,(2,4-dinitro-6-octylphenyl crotonate)] was examined at 25 °C. The estimated DT₅₀ values of [¹⁴C-phenyl]dinocap in pH 5, 7 and 9 buffer solution were 229 days, 56 days and 17 hours, respectively. Cleavage of the crotonate moiety yielded 2,4-dinitro-6-octylphenol(2) as the major product.

Pesticide Type

Fungicide