Pyrazolone

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Pyrazolone is 5-membered heterocycle containing two adjacent nitrogen atoms. It can be viewed as a derivative of pyrazole possessing an additional carbonyl (C=O) group. Compounds containing this functional group are useful commercially in analgesics and dyes. [1]

Contents

Structure and synthesis

Pyrazolone can exist in two isomers: 3-pyrazolone and 4-pyrazolone.

1,2-Dihydro-3H-pyrazol-3-one Structural Formula V1.svg
4H-Pyrazol-4-one Structural Formula V1.svg
Chemical structures of 3-pyrazolone (left) and 4-pyrazolone (right)

These isomers can interconvert via lactam–lactim and imine–enamine tautomerism; these conversion often display photochromism. For pyrazolone derivatives, the 3-pyrazolone isomer can be stabilized with N-alkyl or N-aryl substituents.

Lactam-Lactim-Tautomerie Pyrazolone.svg

The first synthesis of pyrazolones was reported in 1883 by Ludwig Knorr, via a condensation reaction between ethyl acetoacetate and phenylhydrazine. [2]

KnorrPrep.png

Many pyrazolones are produced by functionalization of preformed pyrazolones.

Applications

Pharmaceuticals

Antipyrine (phenazone), the earliest pyrazolone based drug Phenazone2DCSD.svg
Antipyrine (phenazone), the earliest pyrazolone based drug

Pyrazolones are amongst the oldest synthetic pharmaceuticals, starting with the introduction of antipyrine (phenazone) in 1880s. [3] [4] The compounds generally act as analgesics and include dipyrone (Metamizole), aminophenazone, ampyrone, famprofazone, morazone, nifenazone, piperylon and propyphenazone. Of these dipyrone is perhaps the most widely used. [3] [5]

The basic structure has been also used in a number of newer drugs of other effects. [5] Edaravone is useful for prevention and/or therapy of arterial wall injury. [6] Eltrombopag is used to address low blood platelet count.

Dyes

Pyrazolone groups are present in several important dyes. They are commonly used in combination with azo groups to give a sub-family of azo dyes; sometimes referred to as azopyrazolones (tartrazine, orange B, mordant red 19, yellow 2G). Acid Yellow 17, Acid Yellow 23 (tartrazine), Pigment Yellow 13, and Pigment Red 38 are produced on the multi-ton scale annually. [1]

Ligands

Pyrazolones have been studied as ligands. [7]

Related Research Articles

Dye Soluble chemical substance or natural material which can impart color to other materials

A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution, and may require a mordant to improve the fastness of the dye on the fiber.

Pyrrole is a heterocyclic aromatic organic compound, a five-membered ring with the formula C4H4NH. It is a colorless volatile liquid that darkens readily upon exposure to air. Substituted derivatives are also called pyrroles, e.g., N-methylpyrrole, C4H4NCH3. Porphobilinogen, a trisubstituted pyrrole, is the biosynthetic precursor to many natural products such as heme.

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

Tartrazine is a synthetic lemon yellow azo dye primarily used as a food coloring. It is also known as E number E102, C.I. 19140, FD&C Yellow 5, Yellow 5 Lake, Acid Yellow 23, Food Yellow 4, and trisodium 1-(4-sulfonatophenyl)-4-(4-sulfonatophenylazo)-5-pyrazolone-3-carboxylate).

In organic chemistry, an aryl halide is an aromatic compound in which one or more hydrogen atoms, directly bonded to an aromatic ring are replaced by a halide. The haloarene are different from haloalkanes because they exhibit many differences in methods of preparation and properties. The most important members are the aryl chlorides, but the class of compounds is so broad that there are many derivatives and applications.

<span class="mw-page-title-main">Azo compound</span> Class of organic compounds

Azo compounds are compounds bearing the functional group diazenyl R−N=N−R′, in which R and R′ can be either aryl or alkyl.

Acid dye

Acid dyes are anionic, soluble in water and are essentially applied from acidic bath. These dyes possess acidic groups, such as SO3H and COOH and are applied on wool, silk and nylon when ionic bond is established between protonated –NH2 group of fibre and acid group of dye. Overall wash fastness is poor although lightfastness is quite good. As dye and fibre contain opposite electrical nature, strike rate and uptake of acid dye on these fibres is faster; electrolyte at higher concentration is added to retard dye uptake and to form levelled shades. Acid generates cation on fibre and temperature helps to substitute negative part of acid with anionic dye molecules.

Phenazone Chemical compound

Phenazone is an analgesic, antipyretic and anti-inflammatory drug. While it predates the term, it is often classified as a nonsteroidal anti-inflammatory drug (NSAID). Phenazone was one of the earliest synthetic medications — when it was patented in 1883, the only synthetic medical chemicals on the market were chloral hydrate, a sedative, trimethylamine, and iodol (tetraiodopyrrol), an early antiseptic. One of the earliest widely used analgesics and antipyretics, phenazone was gradually replaced in common use by other medications including phenacetin, aspirin, paracetamol and modern NSAIDs such as ibuprofen. However, it is still available in several countries either as an over-the-counter or prescribed drug.

An azo coupling is an organic reaction between a diazonium compound and another aromatic compound that produces an azo compound. In this electrophilic aromatic substitution reaction, the aryldiazonium cation is the electrophile and the activated arene is a nucleophile. In most cases, including the examples below, the diazonium compound is also aromatic.

Pyrazole is an organic compound with the formula C3H3N2H. It is a heterocycle characterized by a 5-membered ring of three carbon atoms and two adjacent nitrogen atoms, which are in ortho-substitution. Pyrazole is a weak base, with pKb 11.5 (pKa of the conjugated acid 2.49 at 25 °C). Pyrazoles are also a class of compounds that have the ring C3N2 with adjacent nitrogen atoms. Notable drugs containing a pyrazole ring are celecoxib (celebrex) and the anabolic steroid stanozolol.

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

Metamizole, or dipyrone, is a painkiller, spasm reliever, and fever reliever that also has anti-inflammatory effects. It is most commonly given by mouth or by intravenous infusion.

Allura Red AC Chemical compound

Allura Red AC is a red azo dye that goes by several names, including FD&C Red 40. It is used as a food dye and has the E number E129.

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

Ohmefentanyl is an extremely potent opioid analgesic drug which selectively binds to the µ-opioid receptor.

Diketene Chemical compound

Diketene is an organic compound with the molecular formula C4H4O2, and which is sometimes written as (CH2CO)2. It is formed by dimerization of ketene, H2C=C=O. Diketene is a member of the oxetane family. It is used as a reagent in organic chemistry. It is a colorless liquid.

2-Naphthol Chemical compound

2-Naphthol, or β-naphthol, is a fluorescent colorless (or occasionally yellow) crystalline solid with the formula C10H7OH. It is an isomer of 1-naphthol, differing by the location of the hydroxyl group on the naphthalene ring. The naphthols are naphthalene homologues of phenol, but more reactive. Both isomers are soluble in simple alcohols, ethers, and chloroform. 2-Naphthol is a widely used intermediate for the production of dyes and other compounds.

Ludwig Knorr German chemist (1859–1921)

Ludwig Knorr was a German chemist. Together with Carl Paal, he discovered the Paal–Knorr synthesis, and the Knorr quinoline synthesis and Knorr pyrrole synthesis are also named after him. The synthesis in 1883 of the analgesic drug antipyrine, now called phenazone, was a commercial success. Antipyrine was the first synthetic drug and the most widely used drug until it was replaced by Aspirin in the early 20th century.

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

Sulfamazone (INN) is a sulfonamide antibiotic with antipyretic properties.

1,4-Dihydroxyanthraquinone Chemical compound

1,4-Dihydroxyanthraquinone, also called quinizarin or Solvent Orange 86, is an organic compound derived from anthroquinone. Quinizarin is an orange or red-brown crystalline powder. It is formally derived from anthraquinone by replacement of two hydrogen atoms by hydroxyl (OH) groups. It is one of ten dihydroxyanthraquinone isomers and occurs in small amounts in the root of the madder plant, Rubia tinctorum.

Alkylbenzene sulfonates Class of chemical compounds

Alkylbenzene sulfonates are a class of anionic surfactants, consisting of a hydrophilic sulfonate head-group and a hydrophobic alkylbenzene tail-group. Along with sodium laureth sulfate, they are one of the oldest and most widely used synthetic detergents and may be found in numerous personal-care products and household-care products . They were first introduced in the 1930s in the form of branched alkylbenzene sulfonates (BAS). However following environmental concerns these were replaced with linear alkylbenzene sulfonates (LAS) during the 1960s. Since then production has increased significantly from about one million tons in 1980, to around 3.5 million tons in 2016, making them most produced anionic surfactant after soaps.

Difenamizole Chemical compound

Difenamizole (INN; brand name Pasalin; former developmental code name AP-14) is a nonsteroidal anti-inflammatory drug (NSAID) and analgesic of the pyrazolone group related to metamizole. It has monoaminergic properties, including inhibition of monoamine oxidase, augmentation of pargyline-induced elevation of striatal dopamine levels, inhibition of K+-induced striatal dopamine release, and inhibition of the reuptake of dopamine.

2-Aminoacetanilide Chemical compound

2-Aminoacetanilide is a chemical compound which is a amino derivative of acetanilide and ortho-isomer of aminoacetanilide. There are two other isomers of aminoacetanilide, 3-aminoacetanilide and 4-aminoacetanilide. Aminoacetanilide derivatives are important synthetic intermediates in heterocyclic and aromatic synthesis. These derivatives have found applications in pharmaceutical industry and dyes and pigment industry.

References

  1. 1 2 Kornis, Gabe I. (2000). "Pyrazoles, Pyrazolines, and Pyrazolones". Kirk-Othmer Encyclopedia of Chemical Technology. doi:10.1002/0471238961.1625180111151814.a01. ISBN   0471238961.
  2. Knorr, Ludwig (July 1883). "Einwirkung von Acetessigester auf Phenylhydrazin". Berichte der Deutschen Chemischen Gesellschaft (in German). 16 (2): 2597–2599. doi:10.1002/cber.188301602194.
  3. 1 2 Brogden, Rex N. (1986). "Pyrazolone Derivatives". Drugs. 32 (Supplement 4): 60–70. doi:10.2165/00003495-198600324-00006. PMID   3552586. S2CID   2761563.
  4. Brune, Kay (December 1997). "The early history of non-opioid analgesics". Acute Pain. 1 (1): 33–40. doi:10.1016/S1366-0071(97)80033-2.
  5. 1 2 Zhao, Zefeng; Dai, Xufen; Li, Chenyang; Wang, Xiao; Tian, Jiale; Feng, Ying; Xie, Jing; Ma, Cong; Nie, Zhuang; Fan, Peinan; Qian, Mingcheng; He, Xirui; Wu, Shaoping; Zhang, Yongmin; Zheng, Xiaohui (2020). "Pyrazolone structural motif in medicinal chemistry: Retrospect and prospect". European Journal of Medicinal Chemistry. 186: 111893. doi:10.1016/j.ejmech.2019.111893. PMC   7115706 . PMID   31761383.
  6. Bailly, Christian; Hecquet, Paul-Emile; Kouach, Mostafa; Thuru, Xavier; Goossens, Jean-François (2020). "Chemical reactivity and uses of 1-phenyl-3-methyl-5-pyrazolone (PMP), also known as edaravone". Bioorganic & Medicinal Chemistry. 28 (10): 115463. doi:10.1016/j.bmc.2020.115463. PMID   32241621. S2CID   214766793.
  7. CASAS, J; GARCIATASENDE, M; SANCHEZ, A; SORDO, J; TOUCEDA, A (June 2007). "Coordination modes of 5-pyrazolones: A solid-state overview". Coordination Chemistry Reviews. 251 (11–12): 1561–1589. doi:10.1016/j.ccr.2007.02.010.