A versatile synthetic route to the preparation of 15N heterocycles
Abstract
A robust medium‐scale (approximately 3 g) synthetic method for 15N labeling of pyridine (15N‐Py) is reported based on the Zincke reaction. 15N enrichment in excess of 81% was achieved with approximately 33% yield. 15N‐Py serves as a standard substrate in a wide range of studies employing a hyperpolarization technique for efficient polarization transfer from parahydrogen to heteronuclei; this technique, called SABRE (signal amplification by reversible exchange), employs a simultaneous chemical exchange of parahydrogen and a to‐be‐hyperpolarized substrate (e.g., pyridine) on metal centers. In studies aimed at the development of hyperpolarized contrast agents for in vivo molecular imaging, pyridine is often employed either as a model substrate (for hyperpolarization technique development, quality assurance, and phantom imaging studies) or as a co‐substrate to facilitate more efficient hyperpolarization of a wide range of emerging contrast agents (e.g., nicotinamide). Here, the produced 15N‐Py was used for the feasibility study of spontaneous 15N hyperpolarization at high magnetic (HF) fields (7 T and 9.4 T) of an NMR spectrometer and an MRI scanner. SABRE hyperpolarization enabled acquisition of 2D MRI imaging of catalyst‐bound 15N‐pyridine with 75 × 75 mm2 field of view (FOV), 32 × 32 matrix size, demonstrating the feasibility of 15N HF‐SABRE molecular imaging with 2.4 × 2.4 mm2 spatial resolution.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 07, 2019
- Source ID
- 10.1002/jlcr.3699
Entities
People
- Boyd M Goodson
- Bryce E. Kidd
- Eduard Y. Chekmenev
- Igor Koptyug
- Kirill V. Kovtunov
- Larisa Kovtunova
- Nikita Chukanov
- Roman Shchepin
- Valery Bukhtiyarov
Organizations
- International Tomography Center
- National Institutes of Health
- Norwegian Nurses Organisation
- Novosibirsk State University
- Russian Academy of Sciences
- Russian Science Foundation
- Southern Illinois University
- United States Department of Defense
- Vanderbilt University
- Wayne State University