66841-25-6

ChEBI: A carboxylic ester resulting from the formal condensation between (1R)-cis-2,2-dimethyl-3-(1,2,2,2-tetrabromoethyl)cyclopropanecarboxylic acid and the alcoholic hydroxy group of (2S)-hydroxy(3-phenoxypheny )acetonitrile.

Insecticide.

Orange-to-yellow resinous solid (technical grade >39%)

The technical drug is a yellow to orange resinous substance. Its relative density is 1.7 (20°C), its vapor pressure is 1.7 Pa (1.73×10-11 Pa) (25°C), and its [α]D is +21°C to +27°C (50 g/L toluene). It is soluble in organic solvents such as acetone, xylene, toluene, dichloromethane, dimethyl sulfoxide, and ethanol; its solubility in water is 70 mg/L. At 50°C, it does not decompose for 6 months and is photostable and non-corrosive.

Insecticide: Not approved for use in EU countries. Registered for use in the U.S.

DETHMOR®; HAG-107®; RU-25472®; RU-25474®; SCOUT®; SCOUT® X-TRA Gel insecticide

Non-systemic with contact and stomach action. Sodium channel modulator.

The laboratory synthesis of Tralomethrin is a multi-step process. The final key step involves the bromination of its precursor, Deltamethrin. Deltamethrin itself is synthesized via the esterification of (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylic acid with (S) cyano-(3-phenoxyphenyl)methanol.
step 1. Synthesis of Deltamethrin (Precursor)
Dissolve (S)-cyano-(3-phenoxyphenyl)methanol in anhydrous toluene in a reaction vessel equipped with a stirrer and under a nitrogen atmosphere. Cool the solution to a low temperature (e.g., -10°C). Slowly add a solution of (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylic acid chloride in anhydrous toluene to the cooled solution. Add a solution of pyridine in toluene dropwise to the reaction mixture. Allow the reaction to proceed at a controlled temperature (e.g., 20°C) for several hours. Upon completion, wash the reaction mixture with dilute hydrochloric acid, followed by a sodium bicarbonate solution. Dry the organic layer over anhydrous sodium sulfate and evaporate the solvent under reduced pressure to obtain crude Deltamethrin. Purify the crude product by a suitable method, such as crystallization or column chromatography.
step 2. Synthesis of Tralomethrin from Deltamethrin
Dissolve Deltamethrin in a suitable solvent in a reaction vessel protected from light. Cool the solution to a low temperature. Slowly add a solution of bromine in the same solvent to the Deltamethrin solution. Stir the reaction mixture at a controlled temperature until the reaction is complete. Remove any excess bromine, for example, by bubbling nitrogen through the solution or by washing with a solution of sodium thiosulfate. Evaporate the solvent under reduced pressure to yield crude Tralomethrin.

Tralomethrin probably owes most of its action to rapid conversion by several mechanisms to deltamethrin. Information on its photodegradation, degradation in soil, and its metabolism in plants, insects and animals has been published and supports this conclusion.

Tralomethrin is stable as a solid but is labile to base. Acidic media reduce the tendency to hydrolysis and epimerisation. It was readily debrominated when solutions or thin films were irradiated at 360 nm or by sunlight. Homolytic fission of a C-Br bond initiates this reaction, which affords deltamethrin (2). Some epimerisation to trans-tralomethrin and thence trans-deltamethrin also occurred. Dehydrobromination also affords deltamethrin and the tribromo derivative (8). Ester cleavage to the acid (3) and to the cyanohydrin (5) and thence to 3PBAl (6) and 3PBA (7) is important in the solid phase but not in solution (Ruzo and Casida, 1981). The products are shown in Scheme 1.

Acute oral LD₅₀ for rats: 99-3,000 mg/kg depending on the carrier used

Insecticide; Veterinary substance