Cysteine as a sustainable sulfur reagent for the protecting-group-free synthesis of sulfur-containing amino acids: biomimetic synthesis of l-ergothioneine in water
作者:Irene Erdelmeier、Sylvain Daunay、Remi Lebel、Laurence Farescour、Jean-Claude Yadan
DOI:10.1039/c2gc35367a
日期:——
Biomass-derived cysteine was used as a sustainable sulfur source for the synthesis of rare sulfur-containing amino acids, such as L-ergothioneine (4), which might be a new vitamin, and various L- or D-2-thiohistidine compounds. Key in this simple, one-pot two-step procedure in water is a bromine-induced regioselective introduction of cysteine followed by a novel thermal cleavage reaction in the presence of thiols, a safer alternative to hazardous red phosphorus. Besides avoiding hazardous sulfur reagents, the new protecting-group-free approach reduces drastically the total number of steps, compared to described procedures. The main drawback, i.e. handling of liquid bromine as an activating and oxidizing reagent in water, was addressed by evaluating four alternative methods using in situ generation of bromine or HOBr, and first encouraging results are described.
生物质来源的半胱氨酸被用作可持续的硫源,用于合成稀有的含硫氨基酸,如可能是一种新维生素的L-厄替奥宁(L-ergothioneine)以及各种L-或D-2-硫组氨酸化合物。该简单的一锅两步水相反应程序的关键是通过溴诱导选择性引入半胱氨酸,然后在硫醇存在下进行新型热裂解反应,这是一种比危险红磷更安全的替代方法。除了避免有害的硫试剂外,这种新的无保护基团的方法大大减少了总步骤数,相较于已有的程序。主要缺点,即在水中处理作为活化和氧化试剂的液溴,已通过评估四种替代方法(使用原位生成溴或次溴酸)进行解决,并描述了初步令人鼓舞的结果。