Over 20% 15N Hyperpolarization in Under One Minute for Metronidazole, an Antibiotic and Hypoxia Probe

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• 作者：Danila A. Barskiy ; Roman V. Shchepin ; Aaron M. Coffey ; Thomas Theis ; Warren S. Warren ; Boyd M. Goodson ; Eduard Y. Chekmenev
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：July 6, 2016
• 年：2016
• 卷：138
• 期：26
• 页码：8080-8083
• 全文大小：294K
• 年卷期：0
• ISSN：1520-5126

文摘

Direct NMR hyperpolarization of naturally abundant ¹⁵N sites in metronidazole is demonstrated using SABRE-SHEATH (Signal Amplification by Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei). In only a few tens of seconds, nuclear spin polarization P_¹⁵N of up to ∼24% is achieved using parahydrogen with 80% para fraction corresponding to P_¹⁵N ≈ 32% if ∼100% parahydrogen were employed (which would translate to a signal enhancement of ∼0.1-million-fold at 9.4 T). In addition to this demonstration on the directly binding ¹⁵N site (using J²_H-¹⁵N), we also hyperpolarized more distant ¹⁵N sites in metronidazole using longer-range spin–spin couplings (J⁴_H-¹⁵N and J⁵_H-¹⁵N). Taken together, these results significantly expand the range of molecular structures and sites amenable to hyperpolarization via low-cost parahydrogen-based methods. In particular, hyperpolarized nitroimidazole and its derivatives have powerful potential applications such as direct in vivo imaging of mechanisms of action or hypoxia sensing.