Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, Utah 84112-0850, United States.
Chem Res Toxicol. 2022 Oct 17;35(10):1809-1813. doi: 10.1021/acs.chemrestox.2c00103. Epub 2022 Jun 1.
Ozonolysis of guanosine formed the 5-carboxamido-5-formamido-2-iminohydantoin (2Ih) nucleoside along with trace spiroiminodihydantoin (Sp). On the basis of literature precedent, we propose an unconventional ozone mechanism involving incorporation of only one oxygen atom of O to form 2Ih with evolution of singlet oxygen responsible for Sp formation. The increased yield of Sp in the buffered O-stabilizing solvent DO, formation of 2Ih in a short oligodeoxynucleotide, and O-isotope labeling provided evidence to support this mechanism. The elusiveness and challenges of working with 2Ih are described in a series of studies on the significant context effects on the half-life of the 2Ih glycosidic bond.
鸟苷的臭氧化作用形成了 5-羧酰胺基-5-甲酰胺基-2-亚氨基海因核苷（2Ih）核苷，同时还有痕量的螺环亚氨基二氢嘧啶（Sp）。根据文献先例，我们提出了一种非传统的臭氧机制，其中只涉及一个氧原子的掺入 O，形成 2Ih，同时释放出 singlet oxygen，后者负责 Sp 的形成。缓冲 O 稳定溶剂 DO 中 Sp 产量的增加、短寡脱氧核苷酸中 2Ih 的形成以及 O 同位素标记提供了证据支持该机制。在一系列关于 2Ih 糖苷键半衰期的显著上下文效应的研究中，描述了与 2Ih 相关的难以捉摸和挑战。
