Molecular Sieve Supported Lanthanum Catalyst for the Efficient Synthesis of Polyhydroquinolines via Hantzsch Synthesis

Zoltán Hell,Ágnes Magyar

doi:10.3311/ppch.10655

Abstract

Molecular sieve supported lanthanum catalyst proved to be an efficient heterogeneous catalyst for the one-pot, four-component synthesis of polyhydroquinoline derivatives from aromatic aldehydes, dimedone, ethyl acetoacetate and ammonium acetate in ethanol via Hantzsch reaction. The method has several advantages such as simple reaction conditions, short reaction time, high yields and simple workup procedure, which make it an attractive route for the synthesis of polyhydroquinolines. The catalyst could be reused several times without the loss of its initial activity.

Highlights

The synthesis of polyhydroquinolines (PHQ) is of considerable interest due to their significant pharmacological and biological properties
In this paper we report a method for the one-pot four-component synthesis of polyhydroquinolines promoted by a heterogeneous, 4 Å molecular sieve supported lanthanum catalyst under mild basic conditions
2 Results and Discussion The structure of the La3+/4 Å molecular sieve (4A) catalyst was investigated by scanning electron microscopy (SEM)

Summary

Introduction

The synthesis of polyhydroquinolines (PHQ) is of considerable interest due to their significant pharmacological and biological properties. Hantzsch described the first method for the preparation of 1,4-dihydropyrimidines via the reaction of aldehydes with ethyl acetoacetate and ammonia in acetic acid or in refluxing alcohols [5]. Their syntheses have been reported under catalyst-free conditions, in refluxing water, but this method suffered from longer reaction times [24].

Results

Conclusion