Chakraborty P K, Kilbourn M R
Department of Internal Medicine, University of Michigan, Ann Arbor 48109.
Int J Rad Appl Instrum A. 1991;42(12):1209-13. doi: 10.1016/0883-2889(91)90199-b.
A new route to aryl [18F]fluorides without electron withdrawing ring substituents has been developed. [18F]Fluorobenzaldehydes, prepared from no-carrier-added (NCA) [18F]fluoride using nucleophilic aromatic substitution of fluoro or nitro groups, were decarbonylated using palladium on charcoal (Pd-C). By this approach 2-methoxy-4-nitrobenzaldehyde was converted to NCA 3-[18F]fluorophenol (25-30%, EOB) and 4-fluoro-2-methoxy-5-methylbenzaldehyde to carrier-added (CA) 3-[18F]fluoro-4-methylphenol (30-40%, EOB). Overall synthesis time was about 2 h. Since the 4-fluoro-2-methoxy-5-methylbenzaldehyde was in turn prepared by methylation and regiospecific formylation of 3-fluoro-4-methylphenol, the overall process represents use of a removable activating group for nucleophilic aromatic substitution with [18F]fluoride for preparation of CA and NCA aryl [18F]fluorides.
已开发出一条合成不含吸电子环取代基的芳基[¹⁸F]氟化物的新路线。通过氟或硝基的亲核芳香取代反应，由无载体添加（NCA）的[¹⁸F]氟化物制备的[¹⁸F]氟苯甲醛，使用钯炭（Pd-C）进行脱羰反应。通过这种方法，2-甲氧基-4-硝基苯甲醛转化为NCA 3-[¹⁸F]氟苯酚（放化产率25 - 30%），4-氟-2-甲氧基-5-甲基苯甲醛转化为加载体（CA）的3-[¹⁸F]氟-4-甲基苯酚（放化产率30 - 40%）。总合成时间约为2小时。由于4-氟-2-甲氧基-5-甲基苯甲醛又是通过3-氟-4-甲基苯酚的甲基化和区域特异性甲酰化反应制备的，因此整个过程代表了使用一个可去除的活化基团进行与[¹⁸F]氟化物的亲核芳香取代反应，以制备CA和NCA芳基[¹⁸F]氟化物。
