Conjugation of a novel histidine derivative to biomolecules and labelling with [99mTc(OH2)3(CO)3]+Electronic supplementary information (ESI) available: complete 1H and 13C NMR spectra of 14, 15, 16 and 19. See http://www.rsc.org/suppdata/ob/b4/b405575f/
作者:Dave R. van Staveren、Stefan Mundwiler、Ulrich Hoffmanns、Jae Kyoung Pak、Bernhard Spingler、Nils Metzler-Nolte、Roger Alberto
DOI:10.1039/b405575f
日期:——
The new histidine derivative 3-1-[3-(9H-fluoren-9-ylmethoxycarbonylamino)-propyl]-1H-imidazol-4-yl}-2-(3-trimethylsilanyl-ethylcarboxyamino)-propionic acid methyl ester (7) has been prepared via alkylation of the histidine urea derivative (7S)-5,6,7,8-tetrahydro-7-(methoxycarbonyl)-5-oxoimidazo-[1,5-c]-pyrimidine (2) with Fmoc-protected 3-iodopropyl-amine, followed by ring opening with 2-trimethylsilylethanol. After Fmoc cleavage by HNEt2, the histidine amine derivative was coupled to biotin, to the pentapeptide leucine-enkephalin and to Vitamin B12-b-acid by amide formation, employing TBTU as the coupling reagent. In order to make the histidine accessible for labelling, the teoc protecting group was removed by either NBu4F (for the biotin conjugate) or by TFA (for the enkephalin and B12 conjugates). Reaction of a 10−4 M solution of the bioconjugates with [99mTc(H2O)3(CO)3]+ at 50 °C for 30 min led to the formation of one single new peak in the HPLC radiochromatogram in each case, confirming quantitative labelling of the respective biomolecules. To assess the nature of the labelled compounds, the rhenium analogues with Re(CO)3 were also synthesised and similar retention times confirmed the identity with the 99mTc labelled conjugates.
新的组氨酸衍生物3-1-[3-(9H-芴-9-基甲氧基羧酰氨基)-丙基]-1H-咪唑-4-基}-2-(3-三甲基硅基-乙基氨基羧酸)-丙酸甲酯(7)通过将组氨酸尿素衍生物(7S)-5,6,7,8-四氢-7-(甲氧基羧基)-5-氧代咪唑-[1,5-c]-嘧啶(2)与Fmoc保护的3-碘丙胺进行烷基化,然后使用2-三甲基硅基乙醇开环反应制备而成。在使用HNEt2去除Fmoc后,将组氨酸胺衍生物通过酰胺形成与生物素、五肽亮氨酸-脑啡肽以及维生素B12-β-酸偶联,采用TBTU作为耦合试剂。为了使组氨酸能够进行标记,teoc保护基团通过NBu4F(用于生物素偶联物)或TFA(用于脑啡肽和B12偶联物)去除。将10−4 M浓度的生物偶联物与[99mTc(H2O)3(CO)3]+在50 °C下反应30分钟,在每个情况下HPLC放射色谱图中产生一个单一的新峰,确认了相应生物分子的定量标记。为了评估标记化合物的性质,还合成了与Re(CO)3的铼类似物,类似的滞留时间确认了与99mTc标记偶联物的身份。