Hsiao Ya-Shan, Yellol Gorakh S, Chen Li-Hsun, Sun Chung-Ming
Department of Chemistry, National Chiao Tung University, Hsinchu 300-10, Taiwan.
J Comb Chem. 2010 Sep 13;12(5):723-32. doi: 10.1021/cc1000902.
A new multidisciplinary synthetic approach comprising polymer-support synthesis, microwave-assisted synthesis, and multicomponent condensation facilitates synthesis of triaza-fluorenes library with a set of advantages such as rapid process, simple purification, and structural diversity in one shot. Microwave-assisted multistep synthetic protocol was used to construct the benzimidazole ring on soluble polymer support using activated aryl-fluorides. The PEG anchored aryl fluoride was condensed with selective primary amines via an ipso-fluoro displacement reaction followed by reduction of nitro group. The subsequent cyclization with cyanogen bromide is used as a key step to furnish immobilized benzimidazoles. Finally multicomponent condensation of resulted polymer bound benzimidazoles with various aldehydes and 1,3-diones under microwave irradiations provides rapid access for triaza-fluorenes with high purity and excellent yields. Microwave irradiation greatly accelerates the rate of all reactions while polymer support facilitates purifications by simple precipitation technique. This strategy dramatically increases efficiency of overall multistep synthesis.
一种新的多学科合成方法，包括聚合物载体合成、微波辅助合成和多组分缩合，有助于一次性合成具有快速反应过程、简单纯化和结构多样性等一系列优点的三氮杂芴库。微波辅助多步合成方案用于在可溶性聚合物载体上使用活化的芳基氟化物构建苯并咪唑环。通过原位氟取代反应将聚乙二醇锚定的芳基氟化物与选择性伯胺缩合，随后还原硝基。随后用溴化氰进行环化是制备固定化苯并咪唑的关键步骤。最后，在微波辐射下，将所得聚合物结合的苯并咪唑与各种醛和1,3 -二酮进行多组分缩合，可快速获得高纯度和高产率的三氮杂芴。微波辐射极大地加快了所有反应的速率，而聚合物载体则通过简单的沉淀技术便于纯化。该策略显著提高了整个多步合成的效率。
