3675-14-7Relevant academic research and scientific papers
Structural Definition of Early Lysine and Histidine Adduction Chemistry of 4-Hydroxynonenal
Nadkarni, Durgesh V.,Sayre, Lawrence M.
, p. 284 - 291 (1995)
The lipid peroxidation product trans-4-hydroxy-2-nonenal (HNE) has been implicated in the covalent modification of low-density lipoproteins (LDL) thought to contribute to the overaccumulation of LDL in the arterial wall in the initial stages of atherosclerosis. Proposals for the exact stuctures of "early" protein side-chain modifications until now have been based on indirect evidence. In this paper, the structures of first-formed His- and Lys-based adducts were elucidated by correlating NMR spectral properties with those obtained on models with reduced chiral center content, in some cases following hydride reduction. In this manner, we could confirm unambiguously the structure of a HNE-His imidazole(Nτ) Michael adduct, stabilized as a cyclic hemiacetal and isolated from a neutral aqueous 1:1 stoichiometry reaction mixture. In the case of Lys/amine reactivity, where an excess of amine is needed to avert HNE aldol condensation, the predominance of a 1:1 Michael adduct in homogeneous aqueous solution and a 1:2 Michael-Schiff base adduct under two-phase aqueous-organic conditions could be verified by isolation of the respective borohydride-reduced forms. The 1:2 adduct, shown to exist as the cyclic hemiaminal, could represent a stable lysine-based cross-link in certain protein microenvironments.
Formation of phenol and carbonyls from the atmospheric reaction of OH radicals with benzene
Berndt, Torsten,Boege, Olaf
, p. 1205 - 1214 (2008/02/07)
The gas-phase reaction of OH radicals with benzene has been studied in a flow tube operated at 295 ± 2 K and 950 mbar of synthetic air or O 2. Ozonolysis of tetramethylethylene (dark reaction) with a measured OH radical yield of 0.92 ± 0.08 or photolysis of methyl nitrite in the presence of NO served as the OH sources. For investigations in the presence of NOx, the conditions were chosen so that more than 95% of the OH/benzene adduct reacted with O2 even for the highest NO2 concentration occurring in the experiment. In the absence of NOx, a phenol yield from the reaction of OH radicals with benzene of 0.61 ± 0.07 was measured by means of long-path FT-IR and UV spectroscopy over a wide range of experimental conditions. This yield was confirmed by measurements performed in the presence of NOx. Detected carbonyls were glyoxal, cis-butenedial and trans-butenedial with formation yields of 0.29 ± 0.10, 0.08 ± 0.03 and 0.023 ± 0.007, respectively, measured in synthetic air and in the presence of NOx. There was no significant difference in the product yields applying both experimental approaches for OH generation (dark reaction or photolysis). Nitrobenzene and o-nitrophenol were detected in traces. The yield of nitrobenzene increased with increasing NO x resulting in a maximum formation yield of 0.007. The detected products in the presence of NOx account for ～78% of the reacted carbon. Butenedial yields from benzene degradation are reported for the first time. In the absence of NOx, glyoxal, cis-butenedial and trans-butenedial were also detected, but with distinctly lower yields compared to the experiments with NOx. the Owner Societies 2006.
Method for production of aldehydes
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, (2008/06/13)
An ether of the following formula (2): (wherein Rais a hydrogen atom, a hydrocarbon group or a heterocyclic group, Rbis a hydrogen atom, a hydroxyl group or a substituted oxy group, and Rcis a hydrocarbon group or a heterocyclic group; Raand Rcmay be combined to form a ring with the adjacent carbon atom and oxygen atom) is reacted with nitrogen monoxide in the presence of a catalyst composed of an imide compound of the following formula (1): (wherein each of R1and R2is, identical to or different from each other, a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cycloalkyl group, a hydroxyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, or an acyl group; R1and R2may be combined to form a double bond, or an aromatic or nonaromatic ring; X is an oxygen atom or a hydroxyl group; and one or two N-substituted cyclic imido groups indicated in the formula (1) may further be formed on R1, R2, or on the double bond or aromatic or nonaromatic ring formed together by R1and R2) to give an aldehyde of the following formula (3): Ra—CHO??(3) (wherein Rahas the same meaning as defined above).
