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Names | |
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Preferred IUPAC name P-(5-Amino-3-phenyl-1H-1,2,4-triazol-1-yl)-N,N,N′,N′-tetramethylphosphonic diamide | |
Other names
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Identifiers | |
3D model (JSmol) | |
ChemSpider | |
ECHA InfoCard | 100.149.164 |
EC Number |
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PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C12H19N6OP | |
Molar mass | 294.299 g·mol−1 |
Appearance | white powder |
0.25 g/L | |
Hazards | |
GHS labelling: | |
Danger | |
H300, H310 | |
P262, P264, P270, P280, P301+P310, P302+P350, P310, P321, P322, P330, P361, P363, P405, P501 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
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. [1]
The phosphoramide Triamiphos is thought to be the first commercially available systemic fungicide. [2] Despite its prominent use in the years following its discovery, no long-term toxicity studies were undertaken until 1974. [3] Further, it has since been replaced by other pesticides. The WHO recommended classification of pesticides by hazard considers triamiphos to be discontinued as use for pesticide. [4]
It is classified as an organophosphorus compound O=P(R)3 and more specifically as a phosphoramide O=P(NR2)3. The bis(dimethylamido)phosphoryl group (Me2N)2-P(O)- is present in triamiphos and also a number of other fungicides. [2]
It contains two chemical groups used in pesticide synthesis (triazole, phosphoryl). The most relevant distinct subparts of the molecule are the oxon centre (O=P) and the leaving group (the triazole aromatic moiety). Triamiphos technically is not an organophosphate O=P(OR)3, a subclass of organophosphorus O=PR3 compounds. However, the distinction is not always consistent throughout literature where organophosphorus compounds without the alkoxy sidechains or even with a O=S group instead of a O=P group are still classified as organophosphate pesticides (OPs). [5] [6]
Schradan, another organophosphorus pesticide, can be seen as analogous to triamiphos, differing only in the leaving group. As both have comparable toxic properties, it can be concluded that the phenylaminotriazole moiety of triamiphos does not appear to be vital for its anticholinesterase property. [3]
Triamiphos was first synthesised by Van den Bos et al. (1960) by adding the salt of 3-amino-5-phenyl-1,2,4-triazole to a solution of phosphoryl chloride. Subsequently, gaseous dimethylamine is introduced into the reaction mixture to yield triamiphos. [7]
There were no studies on the exact determination of the biotransformation route and the active metabolite’s structure of Triamiphos.
The toxic effect of Triamiphos ties back to the acetylcholinesterase inhibition ability of its active metabolite. [8] [9] This inhibitory effect is observed for absorption routes through the skin, respiratory or digestive tract. [10]
The National Institute of Public Health in The Netherlands reported a dose-dependent effect of Triamiphos from a short-term study in rats. They found inhibition of acetylcholinesterase activity at a concentration of 1 ppm during the feeding period. After a recovery period the enzyme activity returned back to normal. [11] A long-term feeding and a three-generation reproduction study performed by Verschuuren et al. (1974), however, found inhibitory effects at an even lower concentration of 0.5 ppm. At this concentration, cholinesterase activity was inhibited in the P-, but not in the F1, F2 or F3 generations. Inhibition in all generations was observed at a concentration of 2.5 ppm, in which the subsequent generations were already exposed to the toxicant from the moment of conception. [3]
A no-effect level of 0.1 ppm was reported by both studies. [3] [11]
Furthermore, a greater inhibitory effect on erythrocyte cholinesterase compared to plasma or brain cholinesterase activity was reported. [3] Therefore, the active metabolite does not appear to readily enter the brain and primarily muscarinic and nicotinic effects are observed. [8] The LD50 (i.p. route) was determined to be between 15 and 18 mg/kg in rats and 10–30 mg/kg in mice. [3] [8] [12] Animals receiving the lethal dose were reported to be maintained upon administration of atropine as antidote. [8] An important factor responsible for the acute toxicity of Triamiphos is the rate of cholinesterase inhibition: if the activity is reduced by 70% within a few minutes, death primarily due to paralysis of the respiratory muscles in rats was reported. The inhibited enzyme is not reactivated and the above-mentioned recovery of the animals was only possible due to its resynthesis. [8] A 1976-study suggested an increased cholesterol content in rat aorta and changes in lipid metabolism as further effects of Triamiphos, which could however not be confirmed by another, more elaborate study. [13] [14] An overview of the effects of Triamiphos at different concentrations can be found in the table below.
Dose | Effect |
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0.1 ppm | NOAEL (no-effect level) [3] [11] |
0.5 ppm | Inhibitory effects in P-generation [3] |
2.5 ppm | Inhibitory effects in P- and subsequent generations [3] |
15–18 mg/kg | Oral LD50 in rats [3] [8] |
10–30 mg/kg | Oral LD50 in mice [12] |
Triamiphos is suspected to exert the same toxic side effects to humans as other organophosphorus pesticides, though no human data on specifically Triamiphos exposure seems to be available. [15]
Soman is an extremely toxic chemical substance. It is a nerve agent, interfering with normal functioning of the mammalian nervous system by inhibiting the enzyme cholinesterase. It is an inhibitor of both acetylcholinesterase and butyrylcholinesterase. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations according to UN Resolution 687. Its production is strictly controlled, and stockpiling is outlawed by the Chemical Weapons Convention of 1993 where it is classified as a Schedule 1 substance. Soman was the third of the so-called G-series nerve agents to be discovered along with GA (tabun), GB (sarin), and GF (cyclosarin).
Malathion is an organophosphate insecticide which acts as an acetylcholinesterase inhibitor. In the USSR, it was known as carbophos, in New Zealand and Australia as maldison and in South Africa as mercaptothion.
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.
In organic chemistry, organophosphates are a class of organophosphorus compounds with the general structure O=P(OR)3, a central phosphate molecule with alkyl or aromatic substituents. They can be considered as esters of phosphoric acid.
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.
Azinphos-methyl (Guthion) is a broad spectrum organophosphate insecticide manufactured by Bayer CropScience, Gowan Co., and Makhteshim Agan. Like other pesticides in this class, it owes its insecticidal properties to the fact that it is an acetylcholinesterase inhibitor. It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act, and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.
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.
Organophosphate poisoning is poisoning due to organophosphates (OPs). Organophosphates are used as insecticides, medications, and nerve agents. Symptoms include increased saliva and tear production, diarrhea, vomiting, small pupils, sweating, muscle tremors, and confusion. While onset of symptoms is often within minutes to hours, some symptoms can take weeks to appear. Symptoms can last for days to weeks.
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.
Tetraethyl pyrophosphate, abbreviated TEPP, is an organophosphate compound with the formula [(C2H5O)2P(O)]2O. It is the tetraethyl derivative of pyrophosphate (P2O74-). It is a colorless oil that solidifies near room temperature. It is used as an insecticide. The compound hydrolyzes rapidly.
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.
Triazofos is a chemical compound used in acaricides, insecticides, and nematicides.
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.