Nitrones compounds

A spin trap is a diamagnetic compound that reacts with a radical by addition of the radical functionality typically to a double bond in the trap, thus forming a new radical that is more stable (better, less unstable) than the original radical. By far the most common class of spin traps are nitrone compounds that, upon addition of the primary radical, produce a stable aminoxyl radical (Figure 10.1). The compound DMPO is the paradigmatic spin trap it is readily available, widely used, and its EPR spectra are relatively easy to interpret. Some of its radical adducts have unpractically short lifetimes. 

The superhyperfine splittings are sufficiently small to ignore second-order effects at X-band, and for adducts of the nitrone compounds splitting from the nitrone-N and the beta-H are the only resolved hyperfine interactions, thus affording the extremely simple resonance condition (cf. Equation 5.10)... 

Carr AA, Thomas CE, Bemotas RC, Ku G. Cyclic nitrone compounds useful in treating stroke, US Patent No. 5498778, March 12, 1996. 

Waterbury LD, Wilcox AL, Carney JM, Mavandadi F, Danielzadeh A. 3,4,5-Trisubstituted aryl nitrone compounds and pharmaceutical compositions containing the same, US Patent No. 0078297, April 24, 2003. 

Narducy KW, Duzman E, Carney JM, Wilcox AL. Ophthalmic Pharmaceutical Compositions Comprising Nitrone Compound and Methods for Treating Ocular Inflammation Using Such Compositions, US Patent No. 5972977, October 26, 1999. 

Kelleher JA, Maples KR, Waterbury LD, Wilcox AL, Xu H, Zhang Y-K. Furan nitrone compounds, US Patent No. 5942507, August 24, 1999. 

Watanabe S, Ishihara T, Itoh KI. Alkali-Soluble Nitrone Compounds and Contrast Enhanced Material Comprising the Same, US Patent No. 5310620, May 10, 1994. 

Stengel KM, Shacklette LW, Eldada L, Yardley JT, Xu C, Zimmerman SM, Horn KA. Nitrone Compounds as Photopolymer Polymerizatin Inhibitors and Contrast Enhancing Additives, US Patent No. 6162579, December 19, 2000. 

The technique of spin-trapping radicals has been applied to the measurement of atmospheric hydroxyl by Watanabe et al. (102), although there are no reports of its use for peroxy radicals. The principle involves the reaction of the radical of interest with an organic nitrone immobilized on a filter paper or other substrate. The sample is returned to the laboratory, and the nitrone-radical product is dissolved in a suitable solvent and measured with EPR. The disadvantages of the spin-trapping technique are difficulty in finding suitable organic nitrone compounds and the fact that most of these molecules are photochemically unstable. 

Spin traps come in basically two types nitroso compounds and nitrone compounds. Reactive free radicals react with the carbon of the nitrone functional group to form a radical adduct that always has a nitroxide group, which is an unusually stable type of free radical. Nitrones are the most useful spin traps for the in vivo detection of free radical metabolites because of the stability of the resulting radical adduct. However, identification of the parent radicals can be difficult because adducts derived from different radicals often have very similar EPR spectra. A comprehensive review of this area through 1992 has recently been published [48]. 

Title 3,4,5-Trisubstituted Aryl Nitrone Compounds and Pharmaceutical Compositions Containing the Same D.L. Waterbury et al., US Patent 6,998,419 (February 14, 2006)... 

Diethoxyphosphinyi-2-buten-4-oli reacts with lithiated dithianes followed by an intermolecular Wittig-Homer reaction to produce fused y-lactones (equation 37). The reaction of 2-lithio-l,3-di-thianes with nitroarenes gives 2- or 4-[(l,3-dithian)-2 -yl]cyclohexa-3,5(or 2,5-)-diene-l-nitronate compounds (conjugate addition products), free nitroarene r cal anions (redox products), 1,3-dithianes and 2,2 -bis( 1,3-dithianes). ... 

A diamagnetic compound (spin trap) is introduced into the radical producing system to give a relatively stable ESR-observable free radical (spin adduct). Typical spin traps are nitrone compounds such as phenyl-ZV-rcrt-butylnitrone (PEN) (8) and 5,5-dimethyl-1-pyrroline-/V-oxide (DMPO) (9) and nitroso compounds such as 2-methyl-2-nitro-sopropane (MNP) (10) and 2.4,6-tri-/crr-butylni-trosobenzene (TEN) (II)... 

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