Pyrazolon derivatives

Phenylhydrazine condenses with acetoacetic ester to give a pyrazolone derivative which on methylation gives phenazone. The sulphonic acid similarly gives rise to the tartrazine dyestuffs. It is used to make indole derivatives by the Fischer process. 

Table 4. U.S. Production and Sales of Selected Pyrazolone Derivatives ...

Some active 5-pyrazolone derivatives (707) and (708) in which the 1-phenyl substituent of antipyrine was replaced by 2 -, 3 - and 4 -pyridyl groups have been prepared (66HCA272). A series of aminoesters substituted at the nitrogen atom of the ester grouping with an antipyryl residue (709) were found to possess local anesthetic properties (69MI40400). 

Pyrazolone derivatives have found many applications as cotton azo dyes because, even if they were more expensive intermediates, they improved qualities such as brightness and light fastness. Rosanthrene Orange (727) and Pyrazol Orange (728) are two representative examples. 

Solid-phase acidic dyes ai e also used in the study of the ternai y systems with pyrazolone derivatives. In addition, the colorless complex of the investigated metals with pyrazolone derivatives has been studied by means of the metal-indicator method. 

The obtained results demonstrated that in a number of cases the solid-phase multiligand systems, and in other cases - pyrazolone derivatives, improve the extraction of metal from the analyzable solution, but at that, the multiligand systems ai e not produced in solid phase. 

Pyrazolone derivatives are analgesic substances that have been known for a long time. The use of antipyrine (phenazone) and aminopyrine was sharply curtailed after their bone marrow toxicity was reported. Other derivatives, however, like phenylbutazone. 

Supplement to c) Pyrazolone derivatives. Derivatives of pyrazolone-(5) are important heterocyclic coupling components. They are based on the following general structure ... 

Rd and Rk represent substituents such as CH3, OCH3, OC2H5, Cl, Br, N02, CF3 in important azo pigments, RD and RK are identical. In some cases, the coupling component may also be a pyrazolone derivative ... 

Suzuki, S., Ishida, Y., Arai, A., Nakanishi, H., and Honda, S. (2003). High-speed electrophoretic analysis of l-phenyl-3-methyl-5-pyrazolone derivatives of monosaccharides on a quartz microchip with whole-channel UV detection. Electrophoresis 24, 3828—3833. 

Acetaminophen, the amphiphilic acids acetylsalicylic acid (ASA), ibuprofen, and others, as well as some pyrazolone derivatives, such as aminopyrine and dipyrone, are grouped under the label antipyretic analgesics to distinguish them from opioid analgesics, because they share the ability to reduce fever. 

Apart from the salicylates NSAIDs include several classes of weak acids like propionic acid derivatives such as ibuprofen, carprofen, fenbufen, fenoprofen, flurbiprofen, ketorolac, loxoprofen, naproxen, oxaprozin, tiaprofenic acid and suprofen. Phenylbutazone is the most important representative of the pyrazolon derivatives which have a bad reputation for their risk of potentially fatal bone-marrow toxicity. To the acetic acid derivatives belong in-domethacin, diclofenac and sulindac. Sulindac is a pro-drug with less toxicity than indomethacin. The enolic acids include piroxicam, droxicam and tenoxicam. Meloxicam is an analog of piroxicam and has a high selectivity for COX-2. 

Pyrazolone derivative related to phenylbutazone. It has uricosuric action. It also inhibits platelet aggregation. 

Metamizole, also known as dipyrone, is a pyrazolone derivative. Metami-zole is administered by intramuscular or intravenous routes to cattle, pigs, sheep, and goats at dosages in the range 15-50 mg/kg bw as an adjunct to therapy in many inflammatory conditions of the musculoskeletal and locomotor systems. 

Suxibuzone, another pyrazolone derivative, is intended for the treatment of inflammatory conditions of the musculoskeletal and locomotor systems in... 

The most widely used method for the synthesis of 4//-pyrazoles employs 2,2-disubstituted 1,3-diketones and hydrazine. Other useful methods include the reaction between l//-pyrazoIes and electrophiles, the transformation of pyrazolone derivatives, and thermal rearrangements of 3//-pyrazoles. 

The pyrazolone derivatives (126) give intensely coloured complexes with zinc(II) ions and have been advocated as reagents for the colorimetric determination of the metal.869... 

The product of the reaction of 3-methyl-l-phenyl-5-pyrazolone with chloride 21c in ethanol in the presence of sodium ethoxide was assigned structure 232 (83MI1). Neither spectral nor elemental analysis data were given to support such an ambiguous assignment, however. As the 5-pyrazolone derivative is an active methylene compound, its reaction with hydrazonoyl halides 21c is expected to give pyrazolo[3,4-c]pyrazole derivative 233, not 232. 

Phenylbutazone, a pyrazolone derivative, rapidly gained favor after its introduction in 1949 for the treatment of rheumatic syndromes, but its toxicities—particularly the hematologic effects (including aplastic anemia)—have resulted in its withdrawal from the North American and most European markets. It is rarely used today. 

These drugs are available in many other countries but are not sold in the USA. Azapropazone (apazone), a pyrazolone derivative, is structurally related to phenylbutazone but appears less likely to cause agranulocytosis. Its half-life of 12-16 hours may be doubled in patients with decreased renal function. Carprofen is a propionic acid derivative with a half-life of 10-16 hours. The indications and adverse effects of azapropazone and carprofen are similar to those of other NSAIDs. 

Acetoacetic acid arylides and pyrazolone derivatives are the coupling components mainly used. Naphtbolsulfonic acids are of only minor importance here. Dehydrothio- p-toluidine sulfonic acid (2) and the sulfonated primulin base are also used as diazo components for certain orange disazo direct dyes. 

Aldopentoses (as l-phenyl-3- methyl-5-pyrazolone derivatives) Nucleosil silica, in-column 3-aminopropylated or Devosil NH2, 3 pm (25 mM HEPES-NaOH, pH 6.0)-acetonitrile (2 1) 345 mm x 100 pm i.d. 250 mm effective length 41 ... 

Monosaccharides of glycopro- DaisoGel silica, in-column teins(as l-phenyl-3-methyl- derivatized by 5-pyrazolone derivatives) octadecyltrimethoxysilane or... 

In the crystal structure of pyrazolone derivatives (Table 21, entry 8), the bond length between H2O and Sn is longer (2.42 A) and the distortion from the ideal TBP geometry (the O—Sn—O axis is bent to 174.8°) is probably due to steric hindrance of the 4-acyl-5-pyrazolonate ligand. In chloroform solution, the adduct loses the molecule of water and adopts a tetrahedral arrangement369. 

Pyrazolone derivatives, specifically phenylbutazone [50-33-9] and, for limited conditions, dipyrone [5907-38-0], are very popular with equine practitioners and are particularly useful in managing cases of lameness and controlling inflammation after trauma or suigery (4). Dipyrone is an analgesic for cases of equine colic. Phenylbutazone is an effective antiinflammatory dmg, but is more toxic than the salicylates, which limits its long-term use. For short-term usage, its ease of administration as injectable or oral preparations makes it a popular product for the equine or small-animal specialist. However, ketoprofen [22071 -15-4] is a new dmg of choice. 

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