Introduction of O-sulfonated poly(4-vinylpyrrolidonium) chloride as a polymeric and reusable catalyst for the synthesis of xanthene derivatives
作者:Farhad Shirini、Peyman Najafi Moghadam、Simin Moayedi、Mohadeseh Seddighi
DOI:10.1039/c4ra04915b
日期:——
O-Sulfonated poly(4-vinylpyrrolidonium) chloride is prepared from the reaction of poly(4-vinylpyrrolidone) [PVP], as a cheap and commercially available reagent, and neat chlorosulfonic acid at room temperature. A variety of techniques including infrared spectra (IR), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), pH analysis and Hammett acidity (Ho) were used to characterize this solid acid. This polymeric reagent showed excellent catalytic activity for the synthesis of xanthene derivatives including 1,8-dioxooctahydroxanthenes, 14-aryl-14H-dibenzo[a,j] xanthenes and 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones under solvent free conditions. The products were formed in excellent yields over short reaction times and the catalyst can be reused several times without any appreciable loss in its activity.
采用廉价的市售试剂聚(4-乙烯基吡咯烷酮)[PVP]和纯氯磺酸在室温下反应制备了O-磺化聚(4-乙烯基吡咯烷酮-氯)。通过红外光谱(IR)、热重分析(TGA)、扫描电子显微镜(SEM)、X射线衍射(XRD)、pH分析和Hammett酸性(Ho)等多种技术对这种固体酸进行了表征。这种聚合物试剂在无溶剂条件下对制备包括1,8-二氧杂八氢吖啶、14-芳基-14H-二苯并[a,j]吖啶和12-芳基-8,9,10,12-四氢苯并[a]吖啶-11-酮在内的吖啶衍生物表现出优异的催化活性。产物的产率很高,反应时间短,催化剂可以重复使用多次而不会明显降低其活性。