125455-49-4

Upstream product

• 32950-71-3 ¹³C-benzonitrile 
• 591-50-4 iodobenzene 
• 263012-32-4 ¹³C₂-ethynylbenzene 

Relevant academic research and scientific papers

Storage of hydrogen spin polarization in long-lived 13C 2 singlet order and implications for hyperpolarized magnetic resonance imaging

Hyperpolarized magnetic resonance imaging (MRI) is a powerful technique enabling real-time monitoring of metabolites at concentration levels not accessible by standard MRI techniques. A considerable challenge this technique faces is the T1 decay of the hyperpolarization upon injection into the system under study. Here we show that AnA′ nXX′ spin systems such as 13C2-1,2- diphenylacetylene (13C2-DPA) sustain long-lived polarization for both 13C and 1H spins with decay constants of almost 4.5 min at high magnetic fields of up to 16.44 T without spin-locking; the T1 of proton polarization is only 3.8 s. Therefore, storage of the proton polarization in a 13C2-singlet state causes a 69-fold extension of the spin lifetime. Notably, this extension is demonstrated with proton-only pulse sequences, which can be readily implemented on standard clinical scanners.

Molybdenum Benzylidyne Complexes for Olefin Metathesis Reactions

The molybdenum benzylidynes [ArCMo(OC(CF3)2CH3)3(1,2-dimethoxyethane)], where Ar = Ph (2a), p-(OCH3)C6H4 (2b), p-(CF3)C6H4 (2c), p-(NO2)C6H4 (2d), or 4-(NO2)-3-(CF3)C6H3 (2e), and [p-(NO2)C6H4CMo(OC(CF3)2CH3)3] (2f) catalyze the ring-closing metathesis (RCM) reaction of diallyl N-tosylamide (3) to produce 1-tosyl-2,5-dihydro-1H-pyrrole (4) and ethylene. The scope of RCM catalytic activity of 2e, cross-metathesis of 1-hexene, and ring-opening metathesis polymerization of cyclooctene were explored. The X-ray crystal structure of 2e was determined. Variable-temperature 1H NMR spectra revealed the formation of intermediates during the reaction of 3 with 2f and the reforming of 2f after completion of the reaction. The use of 13C-labeled Mo benzylidyne did not show transfer of the carbon atom next to Mo to any of the products.

CONTRAST AGENTS BASED ON LONG-LIVED NUCLEAR SINGLET STATES AND RELATED METHODS

Methods are described for preparing magnetic resonance imaging (MRI) and/or magnetic resonance spectroscopy contrast agents where the contrast agents are prepared from precursor molecules having at least four non-zero-spin nuclei that form two pairs of chemically equivalent or effectively equivalent nuclei, e.g., diphenylacetylene or diethyl oxalate. The precursor molecule is hyperpolarized and a sequence of one or more radiofrequency pulses is applied to transfer spin state population between the first and second pair of nuclei, thereby providing a non-equilibrium single state nuclear spin population. To detect the contrast agent, another sequence of one or more radiofrequency pulses is applied to transfer singlet order to polarization. No transformation of the molecular structure of the contrast agent is necessary for detection. Also described are methods of imaging targets using the contrast agents.