TEMPOL

4-Hydroxy-TEMPO

Names
IUPAC name 1-λ1-oxidanyl-2,2,6,6-tetramethylpiperidin-4-ol
Other names tempol; tanol; TMPN; 4-Oxypiperidol; nitroxyl 2; HyTEMPO
Identifiers
CAS Number	2226-96-2 Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL607023 Y
ChemSpider	121639 Y
ECHA InfoCard	100.017.056
PubChem CID	137994
InChI InChI=1S/C9H18NO2/c1-8(2)5-7(11)6-9(3,4)10(8)12/h7,11H,5-6H2,1-4H3 Y Key: UZFMOKQJFYMBGY-UHFFFAOYSA-N Y InChI=1S/C9H18NO2/c1-8(2)5-7(11)6-9(3,4)10(8)12/h7,11H,5-6H2,1-4H3 Key: UZFMOKQJFYMBGY-UHFFFAOYSA-N
SMILES CC1(C)CC(O)CC(C)(C)N1[O]
Properties
Chemical formula	C9H18NO2
Molar mass	172.25 g·mol−1
Appearance	Orange crystals
Melting point	71–73 °C (160–163 °F; 344–346 K)
Hazards
GHS pictograms
GHS signal word	Warning
GHS hazard statements	H302, H315, H319, H335
GHS precautionary statements	P261, P305+351+338
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

4-Hydroxy-TEMPO or TEMPOL, formally 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, is a heterocyclic compound. Like the related TEMPO, it is used as a catalyst and chemical oxidant by virtue of being a stable radical. Its major appeal over TEMPO is that is less expensive, being produced from triacetone amine, which is itself made via the condensation of acetone and ammonia. This makes it economically viable on an industrial scale.

In biochemical research, it has been investigated as an agent for limiting reactive oxygen species. It catalyzes the disproportionation of superoxide, facilitates hydrogen peroxide metabolism, and inhibits Fenton chemistry. It is often present as a structural element in hindered amine light stabilizers, which are commonly used stabilizers in plastics. 4-hydroxy-TEMPO also has significant pharmaceutical activity.