Chemiluminescent energy-transfer cassettes based on fluorescein and nile red
Chemiluminescent energy-transfer cassettes based on fluorescein and nile red
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DOI：
10.1002/anie.200603307
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发表时间：
2007-01-01
影响因子：
16.6
通讯作者：
Burgess, Kevin
中科院分区：
文献类型：
--
作者：
Han, Junyan;Jose, Jiney;Burgess, Kevin
在纯有机非生物体系中诱导化学发光的两种最常见的方法是用碱性过氧化氢处理草酸酯或鲁米诺衍生物。[1，2]这两种类型的混合物都发射相对较短波长的光，这对于生物技术的应用并不理想。例如，鲁米诺在420-450 nm范围内发射，这取决于溶剂介质。[3]草酸酯或鲁米诺的紧密混合物，[4]一种氧化剂，和一种受体染料通过分子间能量转移产生更长波长的发射。这导致了“光棒设备”中令人着迷的长寿命排放。然而，形成用于生物技术的离散探针的选择是有限的，这些探针发射更长的波长，并且通常更有用。[5-10]我们小组正在进行的一个项目的特点是扭曲，但在其他方面共轭，供体和受体盒标记生物分子。[10这样做的动机是能量转移可以通过键以及通过空间发生，因此它可以相对快速和有效。迄今为止，我们所有已发表的研究都以基于紫外线吸收供体（如化合物A）的试剂盒为特色。我们认为这将是有趣的，使卡匣中的供体可能会被化学激活。草酸酯对于通过键能量转移盒不是有用的供体，因为不可能将受体缀合至草酸酯片段。因此，选择了基于鲁米诺的系统。本文描述了基于荧光素和尼罗红的化学活化盒1和2的合成和光谱性质。几乎所有的鲁米诺衍生物几乎不溶于大多数有机介质，这使得它们非常难以操作。经过大量实验，出现了这个问题的一种解决方案：对具有4-甲氧苄基（PMB）基团的化合物（如3）进行双（N-保护）。这种方法得到了有机可溶的、易于色谱分离的中间体，并且在合成的最后阶段通过用三氟乙酸（TFA）处理除去PMB基团。因此，方案1显示了形成化合物1和2的合成。在这两种路线中，环酰肼3是双-N-保护的，然后通过Sonogashira反应[12]进行加工，其特征在于5-溴荧光素[13]和2-羟基尼罗红的衍生物。[14]如果鲁米诺的炔衍生物可以与卤代/三氟甲磺酸化受体偶联，则通向盒的路线将更加收敛，但该方法无效。很难用语言来描述这些化合物的壮观的化学发光，如果没有实验的电影，
The two most common ways to induce chemiluminescence in purely organic, nonbiological systems are to treat either oxalate esters or luminol derivatives with basic hydrogen peroxide.[1, 2] Both these types of mixtures emit light at relatively short wavelengths, which are not ideal for applications in biotechnology. Luminol, for instance, emits in the range 420–450 nm, depending on the solvent media.[3] Intimate mixtures of oxalate esters or luminol,[4] an oxidant, and an acceptor dye give longer wavelength emissions through intermolecular energy transfer. This results in the mesmerizing, long-lived emissions seen in “light-stick devices”. However, the options for forming discrete probes for biotechnology that emit at longer, and generally more useful, wavelengths are limited.[5–10] An ongoing project in our group features twisted, but otherwise conjugated, donor and acceptor cassettes for labeling biomolecules.[10, 11] The motivation for this is that energy transfer can occur through bonds as well as through space, hence it can be relatively fast and efficient. All our published research to date features cassettes based on UV-absorbing donors, like compound A. We thought it would be intriguing to make cassettes where the donor might be activated chemically instead. Oxalate esters are not useful donors for through-bond energy-transfer cassettes because it is impossible to conjugate an acceptor to the oxalate fragment. Consequently, luminol-based systems were selected. Described herein are the syntheses and spectroscopic properties of the fluorescein-and nile red based, chemically activated cassettes 1 and 2. Nearly all luminol derivatives are almost insoluble in most organic media, and this makes them extremely difficult to manipulate. After considerable experimentation, one solution to this problem emerged: bis (N-protection) of compounds like 3 with 4-methoxybenzyl (PMB) groups. This approach gave organic-soluble, easily chromatographed intermediates, and the PMB group is removed in the closing stages of the synthesis through treatment with trifluoroacetic acid (TFA). Thus, Scheme 1 shows the syntheses that evolved to form compounds 1 and 2. In both routes, the cyclic hydrazide 3 was bis-N-protected, then elaborated through Sonogashira reactions [12] featuring derivatives of 5-bromofluorescein [13] and 2-hydroxy nile red.[14] The route to the cassettes would have been more convergent if an alkyne derivative of luminol could have been coupled with halogenated/triflated acceptors, but that approach was ineffective. It is hard to describe in words the spectacular chemiluminescence of these compounds without films of the experi-