AbstractAn electrooxidative C−H functionalization is a widely accepted route to obtain sulfur‐containing arenes and heteroarenes. However, this process often involves using non‐recyclable supporting electrolytes, (co)solvents like hexafluoroisopropanol, additives like acid, or catalysts. The use of additional reagents can increase costs and waste, reducing atom efficiency. Moreover, unlike other nitrogen‐containing heterocycles, there have only been sporadic reports of electrochemical C−H functionalization in fused pyrimidin‐4‐ones, and an electrolyte‐free process has yet to be developed. This work demonstrates that such anodic coupling reactions can be performed in an all‐green electrolytic system without using such additional electrolytes or HFIP, maintaining a high atom economy. This C−H functionalization strategy utilizes inexpensive sodium sulfinates and ammonium thiocyanate as sulfonylating and thiocyanating agents in an undivided cell at a constant current, using a mixture of CH3CN/H2O as solvent at room temperature. Thus, fused pyrimidin‐4‐ones can be selectively converted into C3‐sulfonylated and ‐thiocyanated derivatives in moderate to good yields.
摘要电氧化 C-H 功能化是获得含
硫烯烃和杂环烯烃的一条广为接受的途径。然而,这一过程通常需要使用不可回收的支撑电解质、
六氟异丙醇等(共)溶剂、酸等添加剂或催化剂。使用额外的试剂会增加成本和浪费,降低原子效率。此外,与其他含氮杂环不同,关于融合
嘧啶-4-酮的电
化学 C-H 功能化只有零星报道,而且无电解质工艺尚未开发出来。这项研究表明,这种阳极偶联反应可以在全绿色电解系统中进行,无需使用额外的电解质或 HFIP,从而保持较高的原子经济性。这种 C-H 功能化策略利用廉价的亚
磺酸钠和
硫氰酸铵作为磺化剂和
硫氰酸化剂,在室温下以 CH3CN/
H2O 混合物为溶剂,在恒定电流下在不分流电池中进行。因此,熔融
嘧啶-4-酮可选择性地转化为 C3-磺酰化和
硫氰酸化衍
生物,产率为中等至良好。