Tertiary amine-bisquaternary ammonium functionalized polyacrylonitrile fiber for catalytic synthesis of pyran-annulated heterocycles
作者:Chima E. Anyaegbu、Haonan Zhang、Jian Xiao、Minli Tao、Ning Ma、Wenqin Zhang
DOI:10.1016/j.reactfunctpolym.2022.105201
日期:2022.3
fiber supported bisquaternary ammonium salts with varying interchain quaternary ammonium (QA) to tertiary amine (TA) ratio, counter ions and linker groups were prepared and characterized by TGA, FTIR, XPS, XRD, SEM, EA and water contact angle. The functionalized fibers were used to catalyze three-component reaction (3CR) and tandem deacetalization-3CR for the synthesis of pyrano[4,3-b]pyrans, pyrano[3
制备了具有不同链间季铵 (QA) 与叔胺 (TA) 比例、抗衡离子和连接基团的聚丙烯腈纤维负载双季铵盐,并通过 TGA、FTIR、XPS、XRD、SEM、EA 和水接触角对其进行了表征。功能化纤维用于催化三组分反应(3CR)和串联脱缩醛化-3CR,用于合成吡喃[4,3- b ]吡喃、吡喃[3,2- c ]色烯和吡喃[3,2- c] 喹啉在乙醇-水混合物中。在时间、温度、催化剂用量和溶剂等不同反应条件下,考察了制备的纤维催化剂的催化能力。在最佳条件下,在制备的纤维催化剂中,具有醋酸抗衡离子且链间 QA 与 TA 比为 1:1 的双季铵纤维(PAN BQAc F)表现出最好的催化活性,可连续使用 10 次。催化活性仅略有下降。有趣的是,PAN BQAcF可以有效地催化串联脱缩醛-Knoevenagel反应和相关的新型串联脱缩醛-3CRs,用于合成吡喃环化杂环。在串联脱缩醛化反应中,乙酸根离子在促进质子转移方面发挥着重要作用,这使得