Síntese de α-aminofosfonatos usando Zn[(L)-prolina]2 como um catalisador heterogêneo

Abstract

The α-aminophosphonates belong to a class of compounds that has attracted an increasing attention over the last years due to their structure and important biological activities as amino-acids analogues. They are compounds that may be used as building blocks in several syntheses of biologically active molecules, thus many are the synthetic routes using for it. The most important reaction that enables the formation of the α-aminophosphonates was developed by Martin I. Kabachnik and Ellis K.Fields via a multi component reaction which lead the creator‟s name. In this regard, the multi component reactions have been used as an efficient methodology, adequate to furnish the α-aminophosphonates compounds through a simple and ecofriend synthetic procedure which is in accordance with Green Chemistry principles. Moreover, there are many reports in the literature which involving synthetic routes that present some desadvantages as the stoichiometric catalyst loading. In this sense there will be hard synthetic procedures with low yields and long reaction time. For this reason, the insertion of a new catalyst for Kabachnik-Fields reaction which is able to overcome such disadvantages. In this perspective, this project aimed to develop a new, eco-friend and more efficient synthetic methodology using of a new class of heterogeneous catalyst, the Zn[(L)-proline]2, for Kabachnik-Fields reactions. All the reactions were carried out under magnetic stirring at room temperature and monitored by thin layer chromatography. Several reactions were carried out with different substituted aldehydes and substituted amines and the best results were obtained when was used as aldehydes and amines were substituted by withdraw groups (96-98%) in a short reaction time (45 -50 min). The products were purified by recrystallization and further characterized by melting point, infrared spectroscopy and H1 and C13 nuclear magnetic resonance. The methodology preconized here for the use of Zn[(L)-proline]2 as heterogeneous catalyst in Kabachnick-Fields reactions is a very simple, accessible and efficient methodology which furnished high yields in a very short reaction time.