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2226-96-2 - 4-Hydroxy-TEMPO, free radical, 98+% - 4-Hydroxy-2,2,6,6-tetramethyl-1-piperidin-1-yloxy, free radical - A12497 - Alfa Aesar

A12497 4-Hydroxy-TEMPO, free radical, 98+%

CAS Number
4-Hydroxy-2,2,6,6-tetramethyl-1-piperidin-1-yloxy, free radical

Size Price ($) Quantity Availability
1g 23.04
5g 63.81
25g 237.60
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4-Hydroxy-TEMPO, free radical, 98+%


Chemical Properties

Formula Weight
Melting point
Flash Point
Soluble in water, ethanol, methanol and dimethyl sulfoxide.


Superoxide scavenger with neuroprotective, anti-inflammatory and analgesic effects4-Hydroxy-TEMPO free radical is used as a catalyst and a chemical oxidant by virtue of being a stable radical. It is used for detoxifying reactive oxygen species in medicinal chemistry. It is involved in the catalysis of disproportionation of superoxide and facilitates hydrogen peroxide metabolism. It is used to prepare tris(2,2,6,6-tetramethyl-1-oxyl-4-piperidyloxy)trimellitate by reacting with benzene-1,2,4-tricarbonyl trichloride. Further, it is used as a free radical scavenger and exhibits neuroprotective, anti-inflammatory and analgesic effects. In addition to this, it has good inhibition effect to acrylic acid esters, methyl acrylate, acrylic acid, acrylonitrile, styrene and butadiene.


Store in a cool place. Incompatible with strong oxidizing agents.

Literature References

Reviews: Synthesis and reactions of stable nitroxyl radicals: Synthesis, 190, 401 (1971); Advances in the chemistry of nitroxide spin labels: Chem. Rev., 78, 37 (1978); Recent advances in the chemistry of nitroxides and their applications in spin labelling: J. Sci. Ind. Res., 54, 623 (1995). For a brief feature on derived oxoammonium salts, see: Synlett, 1757 (2003).

Compare also 4-Acetamido-TEMPO, B23456 and TEMPO, A12733.

Recommended as a stabilizer (antioxidant) for the protection of unsaturated fatty acids and their derivatives: J. Am. Chem. Soc., 101, 6748 (1979).

żamoj?, K.; Wiczk, W.; Zaborowski, B.; Jacewicz, D.; Chmurzyński, L. Analysis of Fluorescence Quenching of Coumarin Derivatives by 4-Hydroxy-TEMPO in Aqueous Solution. J. Fluoresc. 2014, 24 (3), 713-718.

żamoj?, K.; Zdrowowicz, M.; Wiczk, W.; Jacewicz, D.; Chmurzyński, L. Dihydroxycoumarins as highly selective fluorescent probes for the fast detection of 4-hydroxy-TEMPO in aqueous solution. RSC Adv. 2015, 5 (78), 63807-63812.

Sunkaria, A.; Sharma, D. R.; Wani, W. Y.; Gill, K. D. Attenuation of Dichlorvos-Induced Microglial Activation and Neuronal Apoptosis by 4-Hydroxy TEMPO. Mol. Neurobiol. 2014, 49 (1), 163-175.

GHS Hazard and Precautionary Statements

Hazard Statements: H318-H315-H302-H335

Causes serious eye damage. Causes skin irritation. Harmful if swallowed. May cause respiratory irritation.

Precautionary Statements: P280-P305+P351+P338-P310

Wear protective gloves/protective clothing/eye protection/face protection. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. Immediately call a POISON CENTER or doctor/physician.

Other References

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