生物活性分子的人工合成在许多生物激发催化应用中取得了丰硕的成果。具体来说,Verdoheme和胆绿素,承载聚吡咯框架,激发了催化剂设计来应对能源和环境挑战。尽管在硬血红素和胆绿素衍生物的台式合成方面取得了显著进展,所有报告的合成,从金属卟啉或难以接近的胆绿素前体开始,需要多个步骤来实现最终所需的产品。此外,这样的合成方法使用多种反应物/氧化还原剂并且涉及通常降低产率的多步骤纯化/萃取过程。然而,只需使用大气中的氧气,血红素加氧酶从血红素选择性地产生硬血红素或胆绿素。受这种酶促途径的激励,我们报道了从其相应的内消旋芳基取代的金属卟啉前体中一步电合成硬血红素或胆绿素衍生物。我们的电合成方法在暴露于空气中的乙腈溶液和合适的电解质中,相对于二茂铁/二茂铁,在0.65V的施加电势下,以>80%的产率产生了铜配位的绿血红素类似物。这些电合成途径在室温下电解8小时内达到最大产物产率。分离出主要产物的白绿素和胆绿素衍生物,纯化,并使用电喷雾质谱进行表征,吸收光谱学,循环伏安法,和核磁共振波谱技术。此外,收集了选择的钴(Co)-和Cu螯合的硬血红素和不含金属的胆绿素产品的X射线晶体学数据。在大环的选择性修饰的电合成路线在一个单一的步骤是未知的,因此,我们相信这份报告将推进电合成策略的范围。
Artificial syntheses of biologically active molecules have been fruitful in many bioinspired catalysis applications. Specifically, verdoheme and biliverdin, bearing polypyrrole frameworks, have inspired catalyst designs to address energy and environmental challenges. Despite remarkable progress in benchtop synthesis of verdoheme and biliverdin derivatives, all reported syntheses, starting from metalloporphyrins or inaccessible biliverdin precursors, require multiple steps to achieve the final desired products. Additionally, such synthetic procedures use multiple reactants/redox agents and involve multistep purification/extraction processes that often lower the yield. However, in a single step using atmospheric oxygen, heme oxygenases selectively generate verdoheme or biliverdin from heme. Motivated by such enzymatic pathways, we report a single-step electrosynthesis of verdoheme or biliverdin derivatives from their corresponding meso-aryl-substituted metalloporphyrin precursors. Our electrosynthetic methods have produced a copper-coordinating verdoheme analog in >80% yield at an applied potential of 0.65 V vs ferrocene/ferrocenium in air-exposed acetonitrile solution with a suitable electrolyte. These electrosynthetic routes reached a maximum product yield within 8 h of electrolysis at room temperature. The major products of verdoheme and biliverdin derivatives were isolated, purified, and characterized using electrospray mass spectrometry, absorption spectroscopy, cyclic voltammetry, and nuclear magnetic resonance spectroscopy techniques. Furthermore, X-ray crystallographic data were collected for select cobalt (Co)- and Cu-chelating verdoheme and metal-free biliverdin products. Electrosynthesis routes for the selective modification at the macrocycle ring in a single step are not known yet, and therefore, we believe that this report would advance the scopes of electrosynthesis strategies.