One-pot four-component synthesis of some novel octahydroquinolindiones using ZnO as an efficient catalyst in water

ZnO has been shown to be an inexpensive, efficient, readily available, and mild catalyst for a one-pot four-component synthesis of some novel octahydroquinolindione-3-carboxylic acid ethyl esters using diethylmalonate, dimedone, ammonium acetate, and appropriate aromatic aldehydes in water at reflux. ZnO acts as a recyclable heterogeneous catalyst to afford the products in excellent yield in short reaction duration.