Radiosynthesis of the fluorinated sucrose analogue, 1′-[<sup>18</sup>F]fluoro-1′-deoxysucrose
作者:Andrew N. Gifford、Caitlin V. Bennett、Joanna S. Fowler
DOI:10.1002/jlcr.2969
日期:2012.10
Fluorinated and deoxysucrose analogues have been proven useful in probing the substrate specificity and roles of sucrose processing enzymes and transporters in plants. To synthesize an 18F-labeled fluorodeoxysucrose analogue suitable for in vivo studies, an acyl-protected, disaccharide-based radiofluorination precursor (sucrose 1′-O-trifluoromethanesulfonyl-2,3,4,6,3′,4′,6′-hepta-O-acetate; 2) was prepared by regioselective mono-deacetylation of sucrose octaacetate using a commercial esterase enzyme followed by conversion of the resultant sucrose heptaacetate to the corresponding triflate. Reaction of this triflate precursor with [18F]fluoride followed by base hydrolysis to remove the acetate groups and HPLC purification gave 1′-[18F]fluoro-1′-deoxysucrose (4) in an overall synthesis time of 80 min and with a median decay corrected yield of 26% (n = 4). This study demonstrates the use of an enzymatic approach to aid the synthesis of a regiospecific radiofluorination precursor starting from the readily available fully acetylated sugar, thus avoiding the need for a complex classical carbohydrate protection strategy to individually protect each hydroxyl group in the molecule. Copyright © 2012 John Wiley & Sons, Ltd.
氟化和脱氧蔗糖类似物已被证明在探究植物中蔗糖加工酶和转运蛋白的底物特异性及其作用方面非常有用。为了合成一种适合体内研究的18F标记的氟脱氧蔗糖类似物,制备了一种酰基保护的基于二糖的放射氟化前体(蔗糖 1'-O-三氟甲磺酰-2,3,4,6,3′,4′,6′-七乙酰酸酯;2),该前体通过使用商业酯酶对蔗糖八乙酸酯进行区域选择性的单脱乙酰化而获得,随后将得到的蔗糖七乙酸酯转化为相应的三氟酸盐。将该三氟酸盐前体与[18F]氟化物反应,并随后通过碱性水解去除乙酸酯基团,经过高效液相色谱(HPLC)纯化,最终在总合成时间为80分钟的情况下获得了1′-[18F]氟-1′-脱氧蔗糖(4),其中位衰变修正产率为26%(n=4)。本研究展示了一种酶促方法,帮助从 readily available 的完全乙酰化糖出发合成一个区域特异性的放射氟化前体,从而避免了对分子中每个羟基进行复杂的传统碳水化合物保护策略的需要。版权 © 2012 John Wiley & Sons, Ltd.