| Title:  TEMPOL CAS Registry Number:  2226-96-2 CAS Name:  4-Hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy Additional Names:  4-hydroxy-TEMPO;  4-hydroxy-2,2,6,6-tetramethyl piperidine N-oxide;  4-hydroxy-2,2,6,6-tetramethylpiperidinooxy Molecular Formula:  C9H18NO2 Molecular Weight:  172.24 Percent Composition:  C 62.76%, H 10.53%, N 8.13%, O 18.58% Literature References:  Stable nitroxyl radical; water-soluble analogue of TEMPO, q.v.  Functions as a membrane-permeable radical scavenger.  Prepn:  E. G. Rozantsev, Bull. Acad. Sci. USSR Div. Chem. Sci. 12, 2085 (1964).  Energy transfer studies:  N. N. Quan, A. V. Guzzo, J. Phys. Chem. 85, 140 (1981).  IR conformation study:  W. A. Bueno, L. Degrève, J. Mol. Struct. 74, 291 (1981).  Solid state NMR spectra:  C. J. Groombridge, M. J. Perkins, J. Chem. Soc. Chem. Commun. 1991, 1164.  LC/MS/MS determn:  I. D. Podmore, J. Chem. Res. Synop. 2002, 574.  Use as a phase transfer catalyst:  X.-Y. Wang et al., Synth. Commun. 29, 157 (1999).  Review of effects in animal models for shock, ischemia-reperfusion injury, and inflammation:  C. Thiemermann, Crit. Care Med. 31, S76-S84 (2003). Properties:  Crystals from ether + hexane, mp 71.5°.  uv max (hexane):  240, 450-500 (e ~1800, ~5).  uv max (ethanol):  242, 435-455 (e ~3800, ~10).  Sol in water. Melting point:  mp 71.5° Absorption maximum:  uv max (hexane):  240, 450-500 (e ~1800, ~5); uv max (ethanol):  242, 435-455 (e ~3800, ~10) Use:  Spin label for EPR studies; phase transfer dehydration catalyst; antioxidant; inhibitor of olefin free radical polymerization.  |