The Second Isolable B12-Thiolate Complex, (Pentafluorophenylthiolato)cobalamin: Synthesis and Characterization

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• 作者：Tsui-Ling Carolyn Hsu ; Nicola E. Brasch ; and Richard G. Finke
• 刊名：Inorganic Chemistry
• 出版年：1998
• 出版时间：October 5, 1998
• 年：1998
• 卷：37
• 期：20
• 页码：5109 - 5116
• 全文大小：205K
• 年卷期：v.37,no.20(October 5, 1998)
• ISSN：1520-510X

文摘

The synthesis, isolation, and characterization of (pentafluorophenylthiolato)cobalamin, C₆F₅SCbl, are reported,only the second isolable RSCbl known. The synthesis of C₆F₅SCbl in 81% yield is accomplished by the dropwiseaddition of 0.93 equiv of C₆F₅SH in MeOH under argon to 1 equiv of HOCbl·HOAc (50.7 mg) in MeOH, all at-15 C and under darkened, red-light-only conditions. The desired C₆F₅SCbl product was precipitated by theaddition of cold, degassed acetone, isolated, and then characterized by FABMS and UV-visible, ¹H NMR, and¹⁹F NMR spectroscopies. Also reported is a ¹H NMR method for the detection of impurities in cobalamins.With the requisite, isolable RSCbl precursor to RS and Cbl radicals now in hand, the needed chemical precedentstudies of the proposed H abstraction step from the substrate in ribonucleoside triphosphate reductase by a RSanalogue of the protein-S site are now possible.