de Oliveira Lima Filho Edson, Malvestiti Ivani
Departamento de Química Fundamental-CCEN-Universidade Federal de Pernambuco, Recife 50740-560, Pernambuco, Brazil.
ACS Omega. 2020 Dec 14;5(51):33329-33339. doi: 10.1021/acsomega.0c05131. eCollection 2020 Dec 29.
Aryl thiocyanate compounds are important building blocks for the synthesis of bioactive compounds and intermediates for several functional groups. Reported thiocyanation reactions C-H functionalization have limited substrate scope and low RME. The ball-milling method reported here uses ammonium persulfate and ammonium thiocyanate as reagents and silica as a grinding auxiliary. It afforded aryl thiocyanates with moderate to excellent yields for a wide variety of aryl compounds (36 examples, 8-96% yield), such as anilines, phenols, anisoles, thioanisole, and indole, thus tolerating substrates with sensitive functional groups. New products such as benzo[][1,3]oxathiol-2-ones were obtained with C-4 substituted phenols. Thus, to our knowledge, we report, for the first time, aryl thiocyanation reaction by ball-milling at room temperature and solvent-free conditions, with short reaction times and no workup. Analysis of several mass-based green metrics indicates that it is an efficient greener method.
芳基硫氰酸酯化合物是合成生物活性化合物的重要基石，也是多种官能团的中间体。报道的C-H官能团化硫氰化反应底物范围有限且反应质量效率低。本文报道的球磨法使用过硫酸铵和硫氰酸铵作为试剂，二氧化硅作为研磨助剂。对于多种芳基化合物（36个例子，产率8-96%），如苯胺、苯酚、苯甲醚、苯甲硫醚和吲哚，该方法能以中等至优异的产率得到芳基硫氰酸酯，因此能够耐受含有敏感官能团的底物。用C-4取代的苯酚得到了新产物，如苯并[][1,3]氧硫杂环丁烷-2-酮。因此，据我们所知，我们首次报道了在室温无溶剂条件下通过球磨进行的芳基硫氰化反应，反应时间短且无需后处理。对几种基于质量的绿色指标的分析表明，这是一种高效的绿色方法。
