Hyperpolarized forms of 1-¹³C-acetates and 1-¹³C-pyruvates are used as diagnostic contrast agents for molecular imaging of many diseases and disorders. Here, we report the synthetic preparation of 1-¹³C isotopically enriched and pure from solvent acetates and pyruvates derivatized with unsaturated ester moiety. The reported unsaturated precursors can be employed for NMR hyperpolarization of 1-¹³C-acetates and 1-¹³C-pyruvates via parahydrogen-induced polarization (PHIP). In this PHIP variant, Side arm hydrogenation (SAH) of unsaturated ester moiety is followed by the polarization transfer from nascent parahydrogen protons to ¹³C nucleus via magnetic field cycling procedure to achieve hyperpolarization of ¹³C nuclear spins. This work reports the synthesis of PHIP-SAH precursors: vinyl 1-¹³C-acetate (55% yield), allyl 1-¹³C-acetate (70% yield), propargyl 1-¹³C-acetate (45% yield), allyl 1-¹³C-pyruvate (60% yield), and propargyl 1-¹³C-pyruvate (35% yield). Feasibility of PHIP-SAH ¹³C hyperpolarization was verified by ¹³C NMR spectroscopy: hyperpolarized allyl 1-¹³C-pyruvate was produced from propargyl 1-¹³C-pyruvate with ¹³C polarization of ∼3.2% in CD₃OD and ∼0.7% in D₂O. ¹³C magnetic resonance imaging is demonstrated with hyperpolarized 1-¹³C-pyruvate in aqueous medium.

中文翻译：

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不饱和前体的合成为仲氢-激发极化和1-分子影像¹³ C-乙酸盐和1- ¹³ C-丙酮酸经由支臂加氢

1-超极化形式的¹³ C-乙酸盐和1- ¹³ C-丙酮酸被用作许多疾病和病症的分子成像诊断造影剂。在这里，我们报告了从不饱和酯部分衍生的溶剂乙酸盐和丙酮酸盐中纯净浓缩的1- ¹³ C同位素的制备方法。所报告的不饱和前体可用于1- NMR超极化¹³ C-乙酸盐和1- ¹³经由仲氢诱导的极化（PHIP）C-丙酮酸盐。在此PHIP变体中，不饱和酯部分的侧臂氢化（SAH）之后是从新生的对氢质子到¹³的极化转移C核通过磁场循环程序实现¹³ C核自旋的超极化。这项工作报告PHIP-SAH前体的合成：1-乙烯基¹³ C-乙酸盐（55％收率），烯丙基1- ¹³ C-乙酸盐（70％产率），炔丙基1- ¹³ C-乙酸盐（45％产率），烯丙基1- ¹³ C-丙酮酸盐（60％产率），和炔丙基1- ¹³ C-丙酮酸盐（35％收率）。PHIP-SAH的可行性¹³ Ç超极化通过验证¹³ C NMR光谱：超极化烯丙基1- ¹³ C-丙酮酸盐是从1-炔丙基生成¹³ C-丙酮酸盐与¹³的~3.2％C极化CD ₃OD和在d ~0.7％₂ O. ¹³ Ç磁共振成像证明与超极化1- ¹³在水性介质中C-丙酮酸盐。