Organothiophosphate

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Organothiophosphates or organophosphorothioates are a subclass of organophosphorus compounds and of thiophosphate compounds. They are the organic compounds that contain a phosphate group in which one or more oxygen atoms is substituted by sulfur. Many are used as pesticides, some have medical applications, and some are used as oil additives. [1] They generally have the chemical formula (RO)3PS, [(RO)2P(S)O], R(RO)2PS, etc.

Contents

Oligonucleotide phosphorothioates (OPS) are modified oligonucleotides where one of the oxygen atoms in the phosphate moiety is replaced by sulfur. These compounds are the basis of antisense therapy, e.g., the drugs fomivirsen (Vitravene), Oblimersen, Alicaforsen, and Mipomersen (Kynamro). [2]

Further examples of these include:

Variants with P=S double bonds were developed as insecticides because of their reduced mammalian toxicity. The phosphorothioate P=S bond is converted to the toxic P=O bond in the target insect. Similar oxidative conversion in mammals is slower, conferring lower toxicity in mammals.

Structure and chemical synthesis

Generally these compounds feature tetrahedral phosphorus(V) centers. Classically, thiophosphates would include a P=S double bond as illustrated by malathion. The terminology is used loosely and thiophosphates include P-S single bonds as illustrated by the drug amifostine. P–S single bonds can be generated through a variety of approaches, starting from thiols, disulfides, sulfinic acids as sulfur sources and various P(III) and P(V) coupling partners. [3] PS–C bonds can also be formed through many comparable approaches, usually by alkylating a free phosphorous thioate anion or thioic acid. [4]

They are conceptually derived from the inorganic thiophosphates (PO4−xS3−
x
). In fact, many are prepared via the intermediacy diorganodithiophosphoric acids, which are prepared by treating phosphorus pentasulfide with alcohols: [1]

P2S5 + 4 ROH → 2 (RO)2PS2H + H2S

Dimethyl dithiophosphoric acid and diethyl dithiophosphoric acid are obtained in this way. The former is a precursor to malathion.

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<span class="mw-page-title-main">Phosphorus</span> Chemical element, symbol P and atomic number 15

Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Earth. It has a concentration in the Earth's crust of about one gram per kilogram. In minerals, phosphorus generally occurs as phosphate.

Oligonucleotides are short DNA or RNA molecules, oligomers, that have a wide range of applications in genetic testing, research, and forensics. Commonly made in the laboratory by solid-phase chemical synthesis, these small bits of nucleic acids can be manufactured as single-stranded molecules with any user-specified sequence, and so are vital for artificial gene synthesis, polymerase chain reaction (PCR), DNA sequencing, molecular cloning and as molecular probes. In nature, oligonucleotides are usually found as small RNA molecules that function in the regulation of gene expression, or are degradation intermediates derived from the breakdown of larger nucleic acid molecules.

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<span class="mw-page-title-main">Parathion</span> Chemical compound

Parathion, also called parathion-ethyl or diethyl parathion and locally known as "Folidol", is an organophosphate insecticide and acaricide. It was originally developed by IG Farben in the 1940s. It is highly toxic to non-target organisms, including humans, so its use has been banned or restricted in most countries. The basic structure is shared by parathion methyl.

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.

<span class="mw-page-title-main">Sodium dithiophosphate</span> Chemical compound

Sodium dithiophosphate is the salt with the formula Na3PS2O2. It is usually supplied as the hydrated solid or as an aqueous solution together with other thiophosphates such as sodium monothiophosphate and sodium trithiophosphate. It is a colorless compound, but commercial samples can appear dark owing to the presence of impurities. It is used to facilitate the isolation of molybdenum from its ores.

<span class="mw-page-title-main">Sodium monofluorophosphate</span> Chemical compound

Sodium monofluorophosphate, commonly abbreviated SMFP, is an inorganic compound with the chemical formula Na2PO3F. Typical for a salt, MFP is odourless, colourless, and water-soluble. This salt is an ingredient in some toothpastes.

Organophosphorus chemistry is the scientific study of the synthesis and properties of organophosphorus compounds, which are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective insecticides, although some are extremely toxic to humans, including sarin and VX nerve agents.

<span class="mw-page-title-main">Thiophosphoryl chloride</span> Chemical compound

Thiophosphoryl chloride is an inorganic compound with the formula PSCl3. It is a colorless pungent smelling liquid that fumes in air. It is synthesized from phosphorus chloride and used to thiophosphorylate organic compounds, such as to produce insecticides.

Oligonucleotide synthesis is the chemical synthesis of relatively short fragments of nucleic acids with defined chemical structure (sequence). The technique is extremely useful in current laboratory practice because it provides a rapid and inexpensive access to custom-made oligonucleotides of the desired sequence. Whereas enzymes synthesize DNA and RNA only in a 5' to 3' direction, chemical oligonucleotide synthesis does not have this limitation, although it is most often carried out in the opposite, 3' to 5' direction. Currently, the process is implemented as solid-phase synthesis using phosphoramidite method and phosphoramidite building blocks derived from protected 2'-deoxynucleosides, ribonucleosides, or chemically modified nucleosides, e.g. LNA or BNA.

<span class="mw-page-title-main">Boranophosphate</span>

Boranophosphates are salts with an anion consisting of borane (BH3) and phosphite groups. One of the simplest examples is [(CH3O)2OPBH3], prepared by base hydrolysis of the adduct of borane and trimethylphosphite.

<span class="mw-page-title-main">Malaoxon</span> Chemical compound

Malaoxon (Liromat, Malation oxon, Malthon oxon) is a chemical compound with the formula C10H19O7PS. More specifically, it is a phosphorothioate. It is a breakdown product of, and more toxic than, malathion.

Thiophosphates (or phosphorothioates, PS) are chemical compounds and anions with the general chemical formula PS
4−x
O3−
x
(x = 0, 1, 2, or 3) and related derivatives where organic groups are attached to one or more O or S. Thiophosphates feature tetrahedral phosphorus(V) centers.

<span class="mw-page-title-main">Chlorethoxyfos</span> Chemical compound

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.

<span class="mw-page-title-main">Tetraethyl pyrophosphate</span> Chemical compound

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.

<span class="mw-page-title-main">Cyanophos</span> Chemical compound

Cyanophos is a cholinesterase inhibitor used as an insecticide and avicide; for example, against rice stem borers and house flies. It is part of the chemical class of organophosphorus compounds, and is a yellow to reddish-yellow transparent liquid.

<span class="mw-page-title-main">Endothion</span> Chemical compound

Endothion is an organic compound used as an insecticide and acaricides. It is part of the chemical class of organophosphorus compounds. It is generally described as white crystals with a slight odor. It is used as an insecticide, but not sold in the United States or Canada.

<span class="mw-page-title-main">Dimethyl dithiophosphoric acid</span> Chemical compound

Dimethyl dithiophosphoric acid is the organophosphorus compound with the formula (CH3O)2PS2H. It is the processor for production of the organothiophosphate insecticide Malathion. Although samples can appear dark, the compound is a colorless, distillable liquid.

<span class="mw-page-title-main">Organophosphinic acid</span>

An organophosphinic acid is an organophosphorus compound with the formula R2−nHnPO2H (R = alkyl, aryl). One or both P-H bonds in the parent hypophosphorous acid (aka phosphinic acid) are replaced by organic groups. The Cyanex family of dialkylphosphinic acids are used in hydrometallurgy to extract metals from ores.

<span class="mw-page-title-main">Cadusafos</span> Thiosulfate insecticide against nematodes

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.

References

  1. 1 2 Svara, Jürgen; Weferling, Norbert; Hofmann, Thomas (2006). "Phosphorus Compounds, Organic". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a19_545.pub2. ISBN   3527306730.
  2. Kurreck, Jens (2003). "Antisense technologies. Improvement through novel chemical modifications". European Journal of Biochemistry. 270 (8): 1628–1644. doi:10.1046/j.1432-1033.2003.03555.x. PMID   12694176.
  3. Jones, David J.; O'Leary, Eileen M.; O'Sullivan, Timothy P. (2020-07-29). "Modern Synthetic Approaches to Phosphorus‐Sulfur Bond Formation in Organophosphorus Compounds". Advanced Synthesis & Catalysis. 362 (14): 2801–2846. doi:10.1002/adsc.202000458. ISSN   1615-4150. S2CID   225475935.
  4. Jones, David J.; O'Leary, Eileen M.; O'Sullivan, Timothy P. (2018-12-05). "Synthesis and application of phosphonothioates, phosphonodithioates, phosphorothioates, phosphinothioates and related compounds". Tetrahedron Letters. 59 (49): 4279–4292. doi:10.1016/j.tetlet.2018.10.058. ISSN   0040-4039. S2CID   105852959.