Hydroxymethyl radical, structure

Organometallic radicals are important intermediates in biological and catalytic reactions. The structure and formation mechanism of radicals trapped in y-irradiated molecular sieves exposed to methanol and ethylene have been studied by EPR spectroscopy. It was found that Ag CH2OH+ radical with one-electron bond between Ag and C is formed by the attack of -CH2OH hydroxymethyl radical on Ag+ cation. 

Table 6.17 Comparison of experimental barriers at 0 K (kJ/mol) for the addition of hydroxymethyl radical C OH to alkenes CH2=CXY with those calculated with wavefunction-based electronic structure methods.8...

Schoneich C, Dillinger U, von Bruchhausen F, Asmus K-D (1992) Oxidation of polyunsaturated fatty adds and lipids through thiyl and sulfonyl radicals reaction kinetics, and influence of oxygen and structure of thiyl radicals. Arch Biochem Biophys 292 456-467 Schuchmann H-P, von Sonntag C (1981) Photolysis at 185 nm of dimethyl ether in agueous solution Involvement of the hydroxymethyl radical. J Photochem 16 289-295 Schuchmann H-P, von Sonntag C (1997) Fleteroatom peroxyl radicals. In Alfassi ZB (ed) Peroxyl radicals. Wiley, Chichester, pp 439-455... 

The major pathways for the fragmentation of kojic acid (81,5-hydroxy-2-hydroxymethyl-pyran-4-one), are shown in Scheme 14 support for each route was provided by the appearance of metastable ion peaks (67MI22203). An RDA cleavage followed by loss of a CH2OH radical produces ion (81a), m/e 69, the structure of which was substantiated by deuteration experiments. The ion at m/e 97 arises by extrusion of CO from the molecular ion and loss of HO- from the side chain structures (81b) and (81c) were proposed. Decomposition of [M]t occurs to give ethylene and an HC=0 fragment. The initial stage involves loss of a -CHO radical from the hydroxymethyl substituent, a process which has... 

Chatgilialoglu C, Castelhano AL, Griller D (1985) Structures and optical absorption spectra of some sulfuranyl radicals in solution. J Org Chem 50 2516-2518 D Alessandro N, Bianchi G, Fang X, Jin F, Schuchmann H-P, von Sonntag C (2000) Reaction of superoxide with phenoxyl-type radicals. J Chem Soc Perkin Trans 2 1862-1867 Das S, von Sonntag C (1986) Oxidation of trimethylamine by OH radicals in aqueous solution, as studied by pulse radiolysis, ESR and product analysis. The reactions of the alkylamine radical cation, the aminoalkyl radical and the protonated aminoalkyl radical. Z Naturforsch 41b 505-513 Das S, Schuchmann MN, Schuchmann H-P, von Sonntag C (1987) The production of the superoxide radical anion by the OH radical-induced oxidation of trimethylamine in oxygenated aqueous solution. The kinetics of the hydrolysis of (hydroxymethyl)dimethylamine. Chem Ber 120 319-323... 

As already mentioned, one of the products of action of hydroxyl radicals on proteins is protein hydroperoxides (G6). Valine and lysine residues are particu-larily susceptible to hydroperoxide formation. Reduction of hydroperoxides produces respective hydroxy derivatives of amino acids. Three valine hydroxides derived from hydroperoxides of this amino acid have been characterized structurally as p-hydroxyvaline [(2S)-2-amino-3-hydroxy-3-methyl-butanoic acid], (2S,3S)-y-hydroxyvaline [(2S,3S)-2-amino-3-hydroxymethyl-butanoic acid], and (2S,3R)-y -hydroxyvaline [(2S,3R)-2-amino-3-hydroxymethyl-butanoic acid (Fig. 12). They are suggested to be possible markers of protein peroxidation (F21). 

Optically active polymers show another properties namely thermosensitivity, e.g., main chains helical poly(iV-isopropylacrylamide) and thermosensitive part as side chain of poly(A -isopropylacrylamide) (PNlPAm). Such type of polymers synthetic method described elsewhere [137]. The polymer with optically active cores (helical polyacetylenes) and thermosensitive shells (PNlPAm) brashes self-assembled core/shell structured nanoparticles in aqueous solution. Another example of optically active polymer is poly[/V-(L)-(l-hydroxymethyl)-pro-pylmethacrylamide] (P(l-HMPMA)) of lower critical solution temperature and thermosensitivity. Circular dichroism and microcalorimetric measurements of the polymer showed the polymer chains in a state of relatively low hydration compared to that of by racemate synthesized monomers by free-radical reaction formed P(d,l-HMPMA). Thermosensitivity and structural effects were obtained by microscopic observation of aqueous solution of polymers and its hydrogels [138]. 

---