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| Names | |
|---|---|
| Preferred IUPAC name O,O-Diethyl O-(1-phenyl-1H-1,2,4-triazol-3-yl) phosphorothioate | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.041.791 |
PubChem CID | |
| UNII | |
CompTox Dashboard (EPA) | |
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| |
| Properties | |
| C12H16N3O3PS | |
| Molar mass | 313.31 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Triazofos is a chemical compound used in acaricides, insecticides, and nematicides.
Triazofos has been registered in the Federal Office of Consumer Protection and Food Safety since 1975 [1] and authorized as an insecticide in the EU until 31 December 2004 (Commission Regulation No 2076/2002). As of 25 July 2003 it was revoked under Commission Regulation No 1336/2003. The production of triazofos began in the 1980s as a Hoechst patent by the company Bayer. [2] In 2011 Bayer announced termination of the sale of this product, due to its poisonous properties. [3]
Triazofos can be synthesized through various reactions.
A method of manufacturing triazofos produces the substance in the presence of triethylamine by reacting 1-phenyl-3-hydroxy-1H-1,2,4-triazole suspended in acetone with diethoxythiophosphoryl chloride. [4]
Another method produces the substance by the reaction of phenylhydrazine with Sodium cyanate, formamide and O,O-diethyl phosphorochlorothioate using cyanate additions, condensation and dehydrochlorination. [4]
An improved process for manufacturing triazofos uses phase transfer catalyst to achieve higher yields and purity. By comprising substituted 1-phenyl 3-hydroxy-1, 2, 4-triazole with 0, -diethylthiophosphoryl chloride in the presence of acide scavengers and 0.2% to 2.0% phase transfer catalyst at a temperature between 20-45 degrees Celsius in a suitable solvent like water. Followed by cooling and separating/extracting the aqueous layer from the organic layer by using a solvent such as xylene, toluene methylene dichloride or water for complete recovery of at least 92% triazofos purity. [5]
Triazofos is available in several forms; as an emulsifiable concentrate (40%), wettable concentrates, wettable powders (30%), ultralow-volume liquids (25%, 40%) and granules (5%) at various concentrations. [6]
Triazofos is an organophosphate pesticide used in acaricides, insecticides and nematicides. [7] Its chemical formula is : C12H16N3O3PS containing a molar mass of 313,31 g/mol. The chemical compound is susceptible to highly toxic and flammable phosphine gas formation in the presence of strong reducing agents (such as hydrides). It belongs to the reactive groups of: amines, phosphines and pyridines. Azo, diazo, azido, hydrazine and organic azide compounds. esters, sulfate esters, phosphate esters, thiophosphate esters and borate esters. Liquids with these reactive groups have been known to react with mineral-based and clay-based absorbents. Furthermore, partial oxidation of the organophosphate can result in the toxic phosphorus oxides release.
The metabolic fate of triazofos has been studied in rats and dogs.
23 female Wistar (WISKf (SPF 71)) rats were given triazofos labelled at the 3 position (radiochemical purity, 98%) as a single oral dose of about 5 mg/kg bw in sesame oil by gastric intubation. [8] Twenty of the rats were used to examine excretion and metabolism and the other three for blood assays.
The maximum blood drug concentration (Cmax) was achieved after about 4 hours. The average half-life (t1⁄2) of radioactivity in the blood was 3.8 hours. After 96 hours, the recovery rate was 98%, indicating that excretion was nearly complete. Over 90% of the administered radioactivity was excreted via the urine within 48 hours. 4.5% of the excretion was accounted for by faecal elimination after 48 hours.
From all the tissues that were analysed, the highest concentration of radioactivity was found in the kidney and the liver, at a relatively low concentration of <0.004 ppm. the urine showed three identifiable metabolites: 1-phenyl-3-hydroxy-(1H)-1,2,4-triazole (43% of the administered dose) and its glucuronide (36%) and sulfate conjugates (13%). The glucuronide was converted back to the parent compound at room temperature, due to it being unstable. Unchanged triazofos was not detected in the urine, and quantities of radioactivity in the faeces were too low for defining of the chemical species.
The metabolic fate of triazofos was also examined in two female beagle dogs, with the same treatment and sampling regimen as for rats. [8] 14C triazofos at a dose of 4.4–4.8 mg/kg bodyweight was administered in sesame oil by gastric intubation. Of the administered dose, an average of 85% after 24 hours and 92% after 48 hours was excreted via the urine. Only 0.3% after 24 hours and 7.2% after 48 hours was accounted for by faecal elimination. Maximum blood drug concentration was achieved after 2 hours. After 48 hours, there was no detectable radioactivity in the blood, and the average half-life was 3.6 hours.
Altogether, the metabolic fate of triazofos in dogs was similar to that in rats . [8] The urine consisted of the same three metabolites as in rats. However, there was one other metabolite found only in the dog's urine representing 11% of the administered dose. It was considered to be another sulfate ester conjugate of the 1-phenyl-3-hydroxy-(1H)-1,2,4-triazole metabolite. There was no unchanged triazofos found in the urine of the dogs. The faeces contained low concentrations of triazofos and the free 1-phenyl-3-hydroxy-(1H)-1,2,4-triazole metabolite as well as five unidentified metabolites at about 0.7, 0.3 and 7.3% of the administered dose, respectively.
The signal of oral poisoning similarly happen in mice, rats and dogs, characterized by tremors, abdominal position, squatting, jerky respiration, lachrymation, salivation, saltatory spasm, tonic convulsions. [9] [10]
Triazofos interacts with several enzymes and signalling pathways according to various bio-assay results: [11] [4]
The use of triazofos as an insecticide in many Asian countries such China, India and Indonesia is widely known due to many insects and pests playing important roles in the market production of staple plant food production. [12] Among various constraints, leafhoppers (Amarasca devastans) and whiteflies (Bemisia tabaci) are one of the major factors in cultivation problems due to their capability to suck the cell sap of plants.
An experiment was conducted by Horticultural Ecosystem in India about the efficacy of triazofos as an insecticide for leafhoppers and whiteflies on Brinjal (Solamum melongena L), one of the prominent crops in India. [13] The investigation was arranged with various market names of triazofos with varying concentrations. The analysis was established after 20 days of transplanting and observing the pest incidence.
Before spraying the insecticide, there were no observations of significant numbers between leafhoppers and whiteflies with the respect to leaf samples. [13]
The visual observations were also constructed in assessing phytotoxic symptoms such as injury on leaf tips or surface, wilting, etc. Nonetheless, no phytotoxic symptoms were observed on the plants with the treatment. In conclusion, the triazofos of 1250 ml/ ha was most effective against leafhoppers, whiteflies and shoot and fruit borer of brinjal. [13]
Triazofos (O,O-diethyl O-1-phenyl-1H-1,2,4-triazol-3-yl phosphorothioate) is considered an organophosphorus pesticide toxicologically by JMPR in 1982, 1986 and 1991. With an ADI of 0–0.001 mg/kg bodyweight. This establishment was made regarding the view of triazofos in causing delayed neurotoxicity. [9] [10]
Toxicological evaluation revealed the maximum level of triazofos which causes no toxicological effect and the maximum level of exposure considered acceptable for humans. The estimated acceptable daily intake for humans is 0–0.001 mg/kg bodyweight.(See Table 2 and 3)
| Mouse | 30 ppm in the diet, equal to 4.5 mg/kg bw/day (2 year of study) |
|---|---|
| Rat | 3 ppm in the diet, equal to 0.17 mg/kg bw/day (2 year of study) |
| Dog | 4 ppm in the diet, equal to 0.12 mg/kg bw/day (1 year of study) |
| Human | 0.0125 mg/kg bw/day (3 week study) |
| Summary | Value | Study | Safety Factor |
|---|---|---|---|
| ADI | 0-0.001 mg/kg bw | 3 weeks, humans | 10 |
| Acute RfD | 0.001 mg/kg bw | 3 weeks, humans | 10 |
Acute exposure to triazofos may produce the following signs and symptoms: sweating, blurred vision, headaches, dizziness, profound weakness, muscle spasms, seizures, coma, mental confusion and psychosis, excessive salivation, nausea, vomiting, anorexia, and diarrhea. [7] Respiratory signs include dyspnoea, pulmonary oedema, respiratory depression and respiratory paralysis. Chest pains are also reported. The organophosphate pesticide contains material with cholinesterase inhibitor which corresponds to the acts on the central nervous system. Organic phosphorus insecticides can be absorbed by the skin, respiratory and gastrointestinal tracts.
The following antidotes can relieve poisoning obtained from triazofos. Pralidoxime, a treatment of choice pralidoxime (Protopam, 2-PAM) can be used as a cholinesterase reactivator in cases of severe poisoning. [11] Less than 48 hours after poisoning, pralidoxime relieves the nicotinic and muscarinic effects. It works by reactivating the cholinesterase and also by slowing the ageing process of phosphorylated cholinesterase to its non-reactivable form. Another antidote is Atropine. Atropine is effective against muscarinic manifestation but not to nicotinic actions such as muscle weakness and twitching and respiratory depression. The use of atropine has been reported to improve respiratory distress, decrease bronchial secretions and increase the oxygenation.
Chlorfenvinphos is the common name of an organophosphorus compound that was widely used as an insecticide and an acaricide. The molecule itself can be described as an enol ester derived from dichloroacetophenone and diethylphosphonic acid. Chlorfenvinphos has been included in many products since its first use in 1963. However, because of its toxic effect as a cholinesterase inhibitor it has been banned in several countries, including the United States and the European Union. Its use in the United States was cancelled in 1991.
Ethion (C9H22O4P2S4) is an organophosphate insecticide. Ethion is known to affect a neural enzyme called acetylcholinesterase and prevent it from working.
Demeton-S-methyl is an organic compound with the molecular formula C6H15O3PS2. It was used as an organothiophosphate acaricide and organothiophosphate insecticide. It is flammable. With prolonged storage, Demeton-S-methyl becomes more toxic due to formation of a sulfonium derivative which has greater affinity to the human form of the acetylcholinesterase enzyme, and this may present a hazard in agricultural use.
Heptachlor is an organochlorine compound that was used as an insecticide. Usually sold as a white or tan powder, heptachlor is one of the cyclodiene insecticides. In 1962, Rachel Carson's Silent Spring questioned the safety of heptachlor and other chlorinated insecticides. Due to its highly stable structure, heptachlor can persist in the environment for decades. In the United States, the Environmental Protection Agency has limited the sale of heptachlor products to the specific application of fire ant control in underground transformers. The amount that can be present in different foods is regulated.
Amitraz is a non-systemic acaricide and insecticide and has also been described as a scabicide. It was first synthesized by the Boots Co. in England in 1969. Amitraz has been found to have an insect repellent effect, works as an insecticide and also as a pesticide synergist. Its effectiveness is traced back on alpha-adrenergic agonist activity, interaction with octopamine receptors of the central nervous system and inhibition of monoamine oxidases and prostaglandin synthesis. Therefore, it leads to overexcitation and consequently paralysis and death in insects. Because amitraz is less harmful to mammals, amitraz is among many other purposes best known as insecticide against mite- or tick-infestation of dogs. It is also widely used in the beekeeping industry as a control for the Varroa destructor mite, although there are recent reports of resistance.
Phosmet is a phthalimide-derived, non-systemic, organophosphate insecticide used on plants and animals. It is mainly used on apple trees for control of codling moth, though it is also used on a wide range of fruit crops, ornamentals, and vines for the control of aphids, suckers, mites, and fruit flies.
Benzotrichloride (BTC), also known as α,α,α-trichlorotoluene, phenyl chloroform or (trichloromethyl)benzene, is an organic compound with the formula C6H5CCl3. Benzotrichloride is an unstable, colorless or somewhat yellowish, viscous, chlorinated hydrocarbon with a penetrating odor. Benzotrichloride is used extensively as a chemical intermediate for products of various classes, i.e. dyes and antimicrobial agents.
Methiocarb is a carbamate pesticide which is used as an insecticide, bird repellent, acaricide and molluscicide since the 1960s. Methiocarb has contact and stomach action on mites and neurotoxic effects on molluscs. Seeds treated with methiocarb also affect birds. Other names for methiocarb are mesurol and mercaptodimethur.
Chlorethoxyfos is an organophosphate acetylcholinesterase inhibitor used as an insecticide. It is registered for the control of corn rootworms, wireworms, cutworms, seed corn maggot, white grubs and symphylans on corn. The insecticide is sold under the trade name Fortress by E.I. du Pont de Nemours & Company.
Demeton, sold as an amber oily liquid with a sulphur like odour under the name Systox™, is an organophosphate derivative causing irritability and shortness of breath to individuals repeatedly exposed. It was used as a phosphorothioate insecticide and acaricide and has the chemical formula C8H19O3PS2. Although it was previously used as an insecticide, it is now largely obsolete due to its relatively high toxicity to humans. Demeton consists of two components, demeton-S and demeton-O in a ratio of approximately 2:1 respectively. The chemical structure of demeton is closely related to military nerve agents such as VX and a derivative with one of the ethoxy groups replaced by methyl was investigated by both the US and Soviet chemical-weapons programs under the names V.sub.X and GD-7.
Carbophenothion also known as Stauffer R 1303 as for the manufacturer, Stauffer Chemical, is an organophosphorus chemical compound. It was used as a pesticide for citrus fruits under the name of Trithion. Carbophenothion was used as an insecticide and acaricide. Although not used anymore it is still a restricted use pesticide in the United States. The chemical is identified in the US as an extremely hazardous substance according to the Emergency Planning and Community Right-to-Know Act.
Sulfotep (also known as tetraethyldithiopyrophosphate and TEDP) is a pesticide commonly used in greenhouses as a fumigant. The substance is also known as Dithione, Dithiophos, and many other names. Sulfotep has the molecular formula C8H20O5P2S2 and belongs to the organophosphate class of chemicals. It has a cholinergic effect, involving depression of the cholinesterase activity of the peripheral and central nervous system of insects. The transduction of signals is disturbed at the synapses that make use of acetylcholine. Sulfotep is a mobile oil that is pale yellow-colored and smells like garlic. It is primarily used as an insecticide.
Leptophos (O-(4-bromo-2,5-dichlorophenyl) O-methyl phenylphosphonothioate) belongs to the organophosphates and at room temperature it is a stable white solid. It is also known as Phosvel, Abar and Vcs 506. Leptophos was primarily used as a pesticide and fungicide. for rice, cotton, fruit and vegetables until its use was discontinued in 1975 in USA, but still sold in South-Eastern Asia in 1981.
Ethoprophos (or ethoprop) is an organophosphate ester with the formula C8H19O2PS2. It is a clear yellow to colourless liquid that has a characteristic mercaptan-like odour. It is used as an insecticide and nematicide and it is an acetylcholinesterase inhibitor.
Terbufos is a chemical compound used in insecticides and nematicides. Terbufos is part of the chemical family of organophosphates. It is a clear, colourless to pale yellow or reddish-brown liquid and sold commercially as granulate.
Triamiphos (chemical formula: C12H19N6OP) is an organophosphate used as a pesticide and fungicide. It is used to control powdery mildews on apples and ornamentals. It was discontinued by the US manufacturer in 1998.
Ethiofencarb is a carbamate insecticide which is useful in controlling aphids on hard and soft fruits and some vegetables. It is not as dangerous as organophosphorous pesticides, but is considered highly toxic to humans in the UK, moderately toxic under US EPA classification, and highly toxic to aquatic life.
Novaluron, or (±)-1-[3-chloro-4-(1,1,2-trifluoro-2-trifluoro- methoxyethoxy)phenyl]-3-(2,6-difluorobenzoyl)urea, is a chemical with pesticide properties, belonging to the class of insecticides called insect growth regulators. It is a benzoylphenyl urea developed by Makhteshim-Agan Industries Ltd.. In the United States, the compound has been used on food crops, including apples, potatoes, brassicas, ornamentals, and cotton. Patents and registrations have been approved or are ongoing in several other countries throughout Europe, Asia, Africa, South America, and Australia. The US Environmental Protection Agency and the Canadian Pest Management Regulatory Agency consider novaluron to pose low risk to the environment and non-target organisms and value it as an important option for integrated pest management that should decrease reliance on organophosphorus, carbamate and pyrethroid insecticides.
Prothioconazole is a synthetic chemical produced primarily for its fungicidal properties. It is a member of the class of compounds triazoles, and possesses a unique toxophore in this class of fungicides. Its effective fungicidal properties can be attributed to its ability to inhibit CYP51A1. This enzyme is required to biosynthesize ergosterol, a key component in the cell membrane of fungi.
Cadusafos is a chemical insecticide and nematicide often used against parasitic nematode populations. The compound acts as a acetylcholinesterase inhibitor. It belongs the chemical class of synthetic organic thiosulfates and it is a volatile and persistent clear liquid. It is used on food crops such as tomatoes, bananas and chickpeas. It is currently not approved by the European Commission for use in the EU. Exposure can occur through inhalation, ingestion or contact with the skin. The compound is highly toxic to nematodes, earthworms and birds but poses no carcinogenic risk to humans.
