Selective synthesis of [2-¹¹C]2-iodopropane and [1-¹¹C]iodoethane using the loop method by reacting methylmagnesium bromide with [¹¹C]car

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• 作者：Ming-Rong Zhang ; Masanao Ogawa ; Yuichiro Yoshida and Kazutoshi Suzuki
• 关键词：&#x5b ; 2-¹¹C&#x5d ; 2-iodopropane ; &#x5b ; 1-¹¹C&#x5d ; iodoethane ; Grignard reaction ; Automated synthesis system ; PET
• 刊名：Applied Radiation and Isotopes
• 出版年：2006
• 出版时间：February 2006
• 年：2006
• 卷：64
• 期：2
• 页码：216-222
• 全文大小：216 K

文摘

[2-¹¹C]2-iodopropane ([2-¹¹C]i-PrI) and [1-¹¹C]iodoethane ([1-¹¹C]EtI) were selectively synthesized using the loop method by reacting methylmagnesium bromide (MeMgBr) with [¹¹C]carbon oxide ([¹¹C]CO₂), followed by treatment with LiAlH₄ and then HI. The loop method, in which a low amount of MeMgBr was used for the Grignard reaction, diminished the formation of non-radioactive iodomethane (MeI) and improved the specific activity of [2-¹¹C]i-PrI and [1-¹¹C]EtI. By examining the reaction temperature and time of MeMgBr with [¹¹C]CO₂ in the loop, we determined the optimal respective conditions of forming [2-¹¹C]i-PrI and [1-¹¹C]EtI. Moreover, [2-¹¹C]i-PrI and [1-¹¹C]EtI could be simultaneously synthesized at a designated ratio in one production run. These substances were obtained by gas chromatographic purification as two radiochemically pure products. All the processes from the production of [¹¹C]CO₂ to the purification of [¹¹C]RI were automated. When we started from about 37 GBq of [¹¹C]CO₂, 3.9–5.3 GBq of [1-¹¹C]EtI or 3.7–4.4 GBq of [2-¹¹C]i-PrI was obtained with a specific activity of 37–99 GBq/μmol at EOS (n