New S-alkyl O-hydrogen sulfothioate functionalized silica-coated magnetic nanoparticles were prepared in a simple method and evaluated as an efficient catalyst in synthesis of mono- and bis-spiro-2-amino-4H-pyrans through three or pseudo-five component reaction of isatins or bis-isatins and malononitrile with dimedone or 4-hydroxycoumarin. The yields were excellent, and the catalyst could be recovered simply from the reaction mixture using an external magnet and reused at least five times without noticeable loss of catalytic activity.
采用简单的方法制备了新型 S-烷基 O-氢
硫代
硫酸酯官能化
二氧化硅包覆磁性纳米粒子,并对其作为一种高效催化剂在通过异
靛红或双异
靛红和
丙二腈与二咪酮或
4-羟基
香豆素的三组份或假五组份反应合成单-和双-螺-2-
氨基-
4H-吡喃中的作用进行了评估。催化剂的产率非常高,而且催化剂可以用外部磁
铁从反应混合物中简单回收,并重复使用至少五次,而不会明显丧失催化活性。