Balandeh Mehrdad, Waldmann Christopher, Shirazi Daniela, Gomez Adrian, Rios Alejandra, Allison Nathanael, Khan Asad, Sadeghi Saman
Department of Molecular & Medical Pharmacology, University of California, Los Angeles, California 90095, USA.
Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095-1569, USA.
J Electrochem Soc. 2017;164(9):G99-G103. doi: 10.1149/2.0941709jes. Epub 2017 Jul 14.
Electrochemical fluorination of methyl(phenylthio)acetate was achieved using tetrabutylammonium fluoride (TBAF). Electrochemical fluorination was performed under potentiostatic anodic oxidation using an undivided cell in acetonitrile containing TBAF and triflic acid. The influence of several parameters including: oxidation potential, time, temperature, sonication, TBAF concentration and triflic acid concentration on fluorination efficiency were studied. It was found that the triflic acid to TBAF concentration ratio plays a key role in the fluorination efficiency. Electrochemical fluorination resulted in formation of mono-fluorinated methyl 2-fluoro-2-(phenylthio)acetate verified by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) Spectroscopy. Under optimum conditions 44 ± 3% mono fluorination yield was obtained after a 30 min electrolysis. Electrochemical radiofluorination for the synthesis of methyl 2-[F]fluoro-2-(phenothio) acetate was also achieved with the same optimized electrochemical cell parameters where TBAF was first passed through an anion exchange resin containing fluorine-18. A radiochemical fluorination efficiency of 7 ± 1% was achieved after 30 min of electrolysis.
使用四丁基氟化铵（TBAF）实现了乙酸甲基（苯硫基）酯的电化学氟化。电化学氟化是在恒电位阳极氧化条件下，使用未分隔的电解池，在含有TBAF和三氟甲磺酸的乙腈中进行的。研究了包括氧化电位、时间、温度、超声处理、TBAF浓度和三氟甲磺酸浓度等几个参数对氟化效率的影响。发现三氟甲磺酸与TBAF的浓度比在氟化效率中起关键作用。通过气相色谱-质谱联用（GC-MS）和核磁共振（NMR）光谱验证，电化学氟化生成了单氟代的2-氟-2-（苯硫基）乙酸甲酯。在最佳条件下，电解30分钟后获得了44±3%的单氟化产率。使用相同的优化电化学电池参数，通过首先使TBAF通过含有氟-18的阴离子交换树脂，也实现了用于合成2-[F]氟-2-（苯硫基）乙酸甲酯的电化学放射性氟化。电解30分钟后，放射化学氟化效率达到7±1%。
