International Tomography Center SB RAS, 3 A Institutskaya St., 630090, Novosibirsk, Russia.
Boreskov Institute of Catalysis SB RAS, 5 Acad. Lavrentiev Pr., 630090, Novosibirsk, Russia.
Chemphyschem. 2021 Jul 2;22(13):1389-1396. doi: 10.1002/cphc.202100156. Epub 2021 May 28.
Magnetic resonance imaging of [1- C]hyperpolarized carboxylates (most notably, [1- C]pyruvate) allows one to visualize abnormal metabolism in tumors and other pathologies. Herein, we investigate the efficiency of H and 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- C-enriched forms with parahydrogen over Rh/TiO catalysts in methanol-d and in D O. The maximum obtained H polarization was 0.6±0.2 % (for propyl acetate in CD OD), while the highest C polarization was 0.10±0.03 % (for ethyl acetate in CD 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 H and 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.
使用 Rh/TiO 催化剂在甲醇-d 和 D2O 中，通过对相应的乙烯基、烯丙基和炔丙基前体进行异相氢化，研究了用乙基、丙基和烯丙基醇基取代的乙酸盐和丙酮酸酯的 H 和 C 超极化效率。在未标记和 1- C 富集形式下用 parahydrogen 进行处理。在获得的最大 H 极化度为 0.6±0.2％（对于 CD3OD 中的丙基乙酸盐），而最高的 C 极化度为 0.10±0.03％（对于 CD3OD 中的乙基乙酸盐）。乙酸盐酯的超极化度超过了丙酮酸酯，而不饱和醇基中具有三碳-碳键的酯作为 parahydrogen 诱导的极化前体的效率低于具有双键的酯。在所研究的化合物中，观察到丙基乙酸盐的最大 H 和 C NMR 信号强度。乙酸乙酯产生的 NMR 信号稍弱，但比其他酯的信号强得多。
