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糖与氨基酸反应涉及一种新的自由基的生成。这种自由基EPR谱特征的超精细结构是由一组两个等性的氮核、三组等性的质子所贡献。谱的超精细特征和谱线分裂的数目主要取决于氨基酸的结构。从~(13)C NMR谱和反应过程的分析,我们提出如下设想:这种新自由基产物应该是1,2-4,5四取代的哌嗪双自由基。用实验中测得的波谱参数在ASPECT-2000型计算机上进行了EPR谱的模拟,模拟的理论谱与实验谱很好地重合,进一步支持了上述的设想。本文还提出了反应中自由基形成的可能机理。
Sugar and amino acid reactions involve a new generation of free radicals. The ultrafine structure of this free radical EPR spectrum feature is contributed by a set of two isotropic nitrogen nuclei, three sets of isotope protons. The ultrafine features of the spectrum and the number of spectral splits depend mainly on the structure of the amino acids. From the analysis of the ~ (13) C NMR spectrum and the reaction process, we propose that the new free radical product should be 1,2,4,5 tetra-substituted piperazine diradical. EPR spectra were simulated on the ASPECT-2000 computer using the spectral parameters measured in the experiment. The simulated theoretical spectrum and the experimental spectrum were well coincident, further supporting the above assumption. The paper also proposed the possible mechanism of free radical formation in the reaction.