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Heterogeneous 1 H and 13 C Parahydrogen‐Induced Polarization of Acetate and Pyruvate Esters
Author(s) -
Salnikov Oleg G.,
Chukanov Nikita V.,
Kovtunova Larisa M.,
Bukhtiyarov Valerii I.,
Kovtunov Kirill V.,
Shchepin Roman V.,
Koptyug Igor V.,
Chekmenev Eduard Y.
Publication year - 2021
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202100156
Subject(s) - chemistry , hyperpolarization (physics) , spin isomers of hydrogen , moiety , medicinal chemistry , propargyl , methanol , vinyl acetate , catalysis , triple bond , nuclear magnetic resonance spectroscopy , stereochemistry , double bond , organic chemistry , hydrogen , polymer , copolymer
Magnetic resonance imaging of [1‐ 13 C]hyperpolarized carboxylates (most notably, [1‐ 13 C]pyruvate) allows one to visualize abnormal metabolism in tumors and other pathologies. Herein, we investigate the efficiency of 1 H and 13 C hyperpolarization of acetate and pyruvate esters with ethyl, propyl and allyl alcoholic moieties using heterogeneous hydrogenation of corresponding vinyl, allyl and propargyl precursors in isotopically unlabeled and 1‐ 13 C‐enriched forms with parahydrogen over Rh/TiO 2 catalysts in methanol‐d 4 and in D 2 O. The maximum obtained 1 H polarization was 0.6±0.2 % (for propyl acetate in CD 3 OD), while the highest 13 C polarization was 0.10±0.03 % (for ethyl acetate in CD 3 OD). Hyperpolarization of acetate esters surpassed that of pyruvates, while esters with a triple carbon‐carbon bond in unsaturated alcoholic moiety were less efficient as parahydrogen‐induced polarization precursors than esters with a double bond. Among the compounds studied, the maximum 1 H and 13 C NMR signal intensities were observed for propyl acetate. Ethyl acetate yielded slightly less intense NMR signals which were dramatically greater than those of other esters under study.