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

Abstract

ZnO has been shown to be an inexpensive, efficient, readily available, and mild catalyst for a one-pot fourcomponent 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.

Lithium perchlorate-, acetic anhydride-, and triphenylphosphine-assisted multicomponent syntheses of 4-unsubstituted 2,5-dioxooctahydroquinoline-3-carboxylates and 3-carbonitriles

“…While aromatic aldehydes have been employed in the multicomponent reaction shown in eq 2 in Scheme 1, the reaction apparently did not take place when formaldehyde was used. 18 The availability of a method that provides the target compounds 5 without a substituent at C4 is of importance to expand the scope of this chemistry. Once an aryl or aliphatic group is present at C4 it will require multiple steps for removal if unsubstituted analogues are desired for biological investigations.…”

“…In the example shown in eq 2, ZnO serves as an efficient catalyst to effect the reaction with aromatic aldehydes in excellent yields, but apparently does not work with formaldehyde or aliphatic aldehydes. 18 When Meldrum’s acid is used in the multicomponent reaction, formaldehyde and aliphatic aldehydes can be employed, but the reaction products lack the 3-carboxylic acid moiety (Scheme 1, eq 3), which is lost by decarboxylation. 17 In related chemistry (Scheme 1, eq 4), hydrazinyl enamines of 1,3-cyclohexanediones, and the arylidenemalonates are preformed and then reacted in the presence of butyl lithium to form the Michael addition products that are subsequently cyclized to yield 4-aryl-2,5-dioxooctahydroquinoline-3-carboxylates.…”

Zinc‐Catalysed Multi‐Component Reactions: An Overview

“…Pasha and co‐workers established a novel protocol towards octahydroquinolindiones via ZnO catalysis . The reaction between diethylmalonate, dimedone, aromatic aldehydes and ammonium acetate was catalysed by ZnO in water medium (Scheme ).…”

Nuclear magnetic resonance, vibrational spectroscopic studies, physico-chemical properties and computational calculations on (nitrophenyl) octahydroquinolindiones by DFT method

“…Recently, we reported a multi-component synthesis of novel octahydroquinolindiones using ZnO as a readily available, inexpensive and environment friendly catalyst [14]. 2 0 -NOHQ and 3 0 -NOHQ were prepared by this method by refluxing a mixture of 2-nitrobenzaldehyde (1 mmol) or 3-nitrobenzaldehyde (1 mmol), diethyl malonate (1 mmol), ZnO (0.025 g, 7.5 mol%) in water (10 mL) for 30 min; dimedone (1 mmol) and ammonium acetate (2 mmol) were then added to the reaction mixture (Scheme 1) and refluxed for the remaining period (90 min).…”