Abstract
A TiO2–SiO2 nanocomposite catalyzes the one-pot cyclocondensation reaction of 1H-indole-2,3-diones (isatins), 1,3-cyclohexanediones, and urea at T = 70°C under solvent-free conditions with high efficiency. The present method affords the corresponding spiro products in high yields and short reaction time. The unique features of the TiO2–SiO2 nanocomposite are high catalytic activity, ease of preparation, non-toxicity, low loading, and recyclability.
摘要
一种TiO2–SiO2纳米复合催化剂在无溶剂条件下,以高效率催化1H-吲哚-2,3-二酮(异酮)、1,3-环己二酮和尿素的一锅式环合反应,反应温度为T = 70°C。该方法可以高产率地生成相应的螺环产物,并且反应时间短。TiO2–SiO2纳米复合催化剂的独特特点是具有高催化活性、易于制备、无毒、负载量低和可重复使用。