4-Ethoxymethylene-2-phenyl-5(4H)-oxazolone in reactions with various heterocyclic amines

Abstract

The analysis of the literature data has showed that there is no information on the behavior in 5(4H)-oxazolones with amines under the conditions of a sealed vessel reactor, which makes it possible to obtain heterocyclic systems with different amines. We have developed and presented an easy, fast, reliable and innovative method for the preparation of a new series of compounds with synthetic and biological potential, based on the interaction of 4-ethoxymethylene-2-phenyl-5(4H)-oxazolone and heterocyclic amines with different ring sizes and sets heteroatoms using a sealed vessel reactor. Based on the results obtained, it has been found that the transformation proceeds by the mechanism of nucleophilic addition of Michael. The scheme of the conducted interaction has been discussed. Initially, the amino group of the amine used is attacked at the exocyclic C=C bond of the initial substrate, ethoxymethylenexazolone, proceeding with the elimination of a well-leaving ethoxy group in the form of an ethanol molecule, which leads to the final 4-hetarylaminomethylidene derivatives of oxazol-5(4H)-one. In the course of the work, it has been found that the use of a sealed vessel reactor makes it possible to reduce the time of transformations, to achieve an increase in selectivity and yields of target products compared to the usual type of activation of the reaction mixture, such as boiling in ethanol. It has been shown that not only the type of activation, but also the nature of the solvent used affects the rate of the reaction. It has been found that under these conditions the transfor mation proceeds with the preservation of the oxazol-5(4Н)-one ring. Control over the course of reactions, determination of individuality and identification of the obtained compounds have been carried out by TLC, elemental analysis, IR-, NMR spectroscopy.