Halogenated carboxylic ester derivatives of phenylethyl imidazole, and their method of preparation are disclosed. Radio-halogenated forms of these compounds are ideally suited for positron-imaging of the adrenal glands, as it is known that these compounds demonstrate a selective and high rate of accumulation in the adrenals. The method of preparing these derivatives proceeds by the conversion of a stable, non-radioactive intermediate having trialkylstannyl leaving groups. These intermediates are efficiently converted to the corresponding halogenated forms by substitution of the trialkylstannyl group with the halogen or radiohalogen.
Chemoenzymatic Synthesis of Stannylated Metomidate as a Precursor for Electrophilic Radiohalogenations ? Regioselective Alkylation of Methyl 1H-Imidazole-5-carboxylate [1]
99%) substituted with iodine in the phenyl ring was prepared from ( S )-1-(4-iodophenyl)ethanol ( ee >98%) obtained by lipase-catalysed resolution and methyl 1 H -imidazole- 5-carboxylate. The two fragments were joined highly regioselectively (alkylation only at N-1 of substituted imidazole) with inversion of configuration using the Mitsunobu reaction. Finally, p -iodometomidate was transformed into the
由( S )-1-(4-碘苯基)乙醇( ee > 98%)通过脂肪酶催化拆分和1 H- 咪唑甲基5-羧酸甲酯制得 在苯环中被碘取代的甲酰胺基( ee 99%) 。使用 Mitsunobu 反应将两个片段高度区域选择性地连接(仅在取代的咪唑的N-1处烷基化),并且构型反转 。最终, 将对 碘代苯甲酸酯转化为 对 三甲基锡烷基衍生物。