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2564-83-2 - TEMPO, free radical, 98+% - 2,2,6,6-Tetramethyl-1-piperidinyloxy, free radical - A12733 - Alfa Aesar

A12733 TEMPO, free radical, 98+%

CAS Number
2,2,6,6-Tetramethyl-1-piperidinyloxy, free radical

Size Price ($) Quantity Availability
1g 17.10
5g 44.10
25g 147.60
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TEMPO, free radical, 98+%


Chemical Properties

Formula Weight
Melting point
Boiling Point
193° dec.
Flash Point
Soluble in all organic solvents. Insoluble in water.


TEMPO is used as a catalyst in organic synthesis and for the oxidation of primary alcohols to aldehydes. It finds use in the chemical industry for conversion of bisnoralcohol (a steroid) to bisnoraldehyde. It acts as a free radical scavenger, as a mediator in controlled radical polymerization and as a structural probe in electron spin resonance spectroscopy. Further, it is involved in the preparation of (S)-(+)-2-methylbutanal from (S)-(-)-2-methyl-1-butanol.


Store in a cool place. Incompatible withstrong oxidizing agents and strong acids.

Literature References

For brief features on TEMPO and related reagents, see: Synlett, 563 (2001); 1757 (2003); 657 (2006). For reviews on nitroxide radicals, see: Synthesis, 190, 401 (1971); Chem. Rev., 78, 37 (1978); J. Sci. Ind. Res., 54, 623 (1995).

In the presence of a catalytic amount of KBr, catalyzes the selective oxidation of primary and secondary alcohols to aldehydes and ketones by buffered NaOCl: J. Org. Chem., 50, 4888 (1985); 52, 2559 (1987); Org. Synth. Coll., 8, 367 (1993). High yields of aldehydes can also be obtained under mild, phase-transfer conditions with Oxone®: Org. Lett., 2, 1173 (2000). In the presence of CuCl, aerobic oxidation of alcohols to aldehydes and ketones has been accomplished in the ionic liquid 1-n-Butyl-3-methyl­imidazolium hexafluorophosphate, L19086: Org. Lett., 4, 1507 (2002). With NaOCl, ɑ-amino or ɑ-alkoxy alcohols have also been oxidized to the aldehydes: Tetrahedron Lett., 33, 5029 (1992). The use of I2 as cooxidant is useful for sensitive substrates: Org. Lett., 5, 235 (2003).

The addition of quaternary salts to the reaction mixture permits further oxidation of aldehydes to acids. Selective oxidation of a primary OH to an aldehyde can be achieved in the presence of a secondary OH: J. Org. Chem., 54, 2970 (1989); Tetrahedron Lett., 31, 2177 (1990). The oxidation can also be performed using NCS under phase-transfer conditions: J. Org. Chem., 61, 7452 (1996), with Iodosobenzene diacetate, B24531: J. Org. Chem., 62, 6974 (1997), or Trichloroisocyanuric acid, B23906: Org. Lett., 3, 3041 (2001).

For a review of the use of stable nitroxyl radicals for the oxidation of primary and secondary alcohols, see: Synthesis, 1153 (1996).

Cf also 4-Hydroxy-TEMPO, A12497, and 4-Acetamido-TEMPO, B23456.

Chernick, E. T.; Casillas, R.; Zirzlmeier, J.; Gardner, D. M.; Gruber, M.; Kropp, H.; Meyer, K.; Wasielewski, M. R.; Guldi, D. M.; Tykwinski, R. R. Pentacene Appended to a TEMPO Stable Free Radical: The Effect of Magnetic Exchange Coupling on Photoexcited Pentacene. J. Am. Chem. Soc. 2015, 137 (2), 857-863.

Zhu, X.; Chiba, S. TEMPO-mediated allylic C-H amination with hydrazones. Org. Biomol. Chem. 2014, 12 (26), 4567-4570.

GHS Hazard and Precautionary Statements

Hazard Statements: H314-H318

Causes severe skin burns and eye damage. Causes serious eye damage.

Precautionary Statements: P260-P280-P303+P361+P353-P305+P351+P338-P301+P330+P331-P304+P340-P310-P363-P405-P501a

Do not breathe dust/fume/gas/mist/vapours/spray. Wear protective gloves/protective clothing/eye protection/face protection. IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water/shower. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. IF SWALLOWED: Rinse mouth. Do NOT induce vomiting. IF INHALED: Remove to fresh air and keep at rest in a position comfortable for breathing. Immediately call a POISON CENTER or doctor/physician. Wash contaminated clothing before reuse. Store locked up. Dispose of contents/container in accordance with local/regional/national/international regulations.

Other References

Hazard Class
Packing Group
Harmonized Tariff Code


  • 33369

    Sodium hypochlorite, 11-15% available chlorine
  • 89892

    Oxone®, monopersulfate
  • B24531

    Iodosobenzene diacetate, 98+%
  • 11043

    Ruthenium(III) chloride hydrate, 99.9% (PGM basis), Ru 38% min
  • A10312

    N-Hydroxysuccinimide, 98+%

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