2-Amino-2′-[18F]fluorobenzhydrols, intermediates for the synthesis of [2′-18F]-1,4-benzodiazepine-2-ones
作者:Peter Johnström、Sharon Stone-Elander
DOI:10.1002/jlcr.2580340206
日期:1994.2
A method for synthesizing 18F-labelled 2-amino-2′-fluorobenzhydrols under nocarrier-added conditions for use as radiolabelled intermediates in the synthesis of[2′-18F]-1,4-benzodiazepine-2-ones is presented. Anilinodichloroborane reagents were formed by the reaction of boron trichloride with 4-chloro-N-methylaniline, 6a, 4-nitro-N-methylaniline, 6b, 4-nitro-N-ethylaniline, 6c, and 4-chloro-N-(2,2,2-trifluoroethyl)aniline, 6d. 2-[18F]Fluorobenzaldehyde, 5, synthesized in 55–70% yields by the nucleophilic aromatic substitution of 2-nitrobenzaldehyde with the Kryptofix/K+ complex of [18F]F−, was subsequently reacted with the anilinodichloroborane coupling reagents with aromatic substitution occurring ortho to the amino group. The resulting 2-amino-2′-[18F]fluorobenzhydrols, 7a - 7d, were produced in conversions of 60–95% with reaction time ⩽ 10 min at room temperature or 60°C, depending on the aniline used. The total synthesis time, including evaporation of the target water, was 60–65 min. The total radiochemical conversions were of the order of 50–65% for 7a - 7c and 35–45% for 7d, decay-corrected and based on [18F]F−.
本文介绍了一种在无载体添加条件下合成18F标记的2-氨基-2'-氟苯醇的方法,该产品可用作合成[2'-18F]-1,4-苯二氮卓-2-酮的放射性标记中间体。通过三氯化硼与4-氯-N-甲基苯胺、4-硝基-N-甲基苯胺、4-硝基-N-乙基苯胺和4-氯-N-(2,2,2-三氟乙基)苯胺的反应,形成了苯胺二氯硼酸盐试剂。合成的2-[18F]氟苯甲醛通过2-硝基苯甲醛与Kryptofix/K+复合物[18F]F−进行亲核芳香取代,产率为55-70%。随后,将其与苯胺二氯硼酸盐偶联试剂反应,在氨基附近发生芳香取代反应。最终得到的2-氨基-2'-[18F]氟苯醇产率为60-95%,反应时间在室温或60°C下不超过10分钟,具体取决于所用的苯胺。整个合成时间,包括目标水的蒸发,约为60-65分钟。对于7a-7c,总放射化学转化率为50-65%,而对于7d为35-45%,已进行衰变校正,并基于[18F]F−。