Preparation, characterization, and catalysis application of nano-rods zinc oxide in the synthesis of 3-indolyl-3-hydroxy oxindoles in water

Abstract ZnO nano-rods is synthesized successfully by a new method employing Zn(OAc) 2 ·2H 2 O, NH 3 and polyethylene glycol (PEG, M w  = 2000). X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and BET surface area measurement were used to characterize the structure and morphology of the catalyst. Nano-rods ZnO has been found highly effective and recyclable catalyst for synthesis of 3-indolyl-3-hydroxy oxindole derivatives by Friedel–Crafts reaction of indole with isatins in excellent yields, in water.