Kondo T, Murali Krishna C, Riesz P
Radiation Oncology Branch, National Cancer Institute, Bethesda, Maryland 20892.
Radiat Res. 1988 Oct;116(1):56-73.
The sonolysis of aqueous solutions of various dihydropyrimidines and substituted pyrimidines was investigated by ESR and spin trapping with the nonvolatile, water soluble spin trap, 3,5-dibromonitrosobenzene sulfonate (DBNBS) and its deuterated analog to examine the possibility of detecting new radicals specifically generated in the high temperature zones produced by collapsing cavitation bubbles. Similar ESR spectra were obtained from sonolysis of argon-saturated aqueous solutions, from uv photolysis of aqueous solutions containing H2O2, and from gamma radiolysis of nitrous oxide saturated solutions, although sonolysis of aqueous solutions leads to the formation of pyrimidine radicals by H atom as well as OH radical addition to the 5,6 double bond of pyrimidines. No evidence for specific new radicals formed in the high temperature regions induced by cavitation could be found. For the reactions of dihydropyrimidines with hydroxyl radicals additional spin adducts could be detected and identified with the spin trap DBNBS compared to 2-methyl-2-nitrosopropane which was used in previous studies; however, for alkylpyrimidines fewer spin adducts were observed. The use of the deuterated analog of DBNBS is helpful for unambiguous radical structure assignment.
通过电子自旋共振（ESR）以及使用非挥发性水溶性自旋捕捉剂3,5 - 二溴亚硝基苯磺酸盐（DBNBS）及其氘代类似物进行自旋捕捉，研究了各种二氢嘧啶和取代嘧啶水溶液的声致分解，以检验检测在空化气泡崩溃产生的高温区域中特异性生成的新自由基的可能性。尽管嘧啶水溶液的声致分解通过氢原子以及羟基自由基加成到嘧啶的5,6双键上导致嘧啶自由基的形成，但从氩饱和水溶液的声致分解、含过氧化氢水溶液的紫外光解以及一氧化二氮饱和溶液的γ辐射分解中获得了相似的ESR光谱。未发现由空化诱导的高温区域中形成特定新自由基的证据。与先前研究中使用的2 - 甲基 - 2 - 亚硝基丙烷相比，对于二氢嘧啶与羟基自由基的反应，可以检测并用自旋捕捉剂DBNBS鉴定出更多的自旋加合物；然而，对于烷基嘧啶，观察到的自旋加合物较少。使用DBNBS的氘代类似物有助于明确自由基结构的归属。
