Synthesis of hydrazone derivatives of isonicotinic acid under microwave activation conditions

Abstract

In the article the results of studying the reaction of the interaction of isonicotinic acid hydrazide with various derivatives of aromatic aldehydes under conditions of microwave activation in an alcohol medium were described. The results of studying the dependences of the hydrazone yield on the duration of the activation time at various microwave irradiation powers in comparison with the classical method have been presented. It was found that the main factors affecting the nature of the synthesis and the yields of the target products were the power and time of microwave activation, as well as the structural features of the reactants. For all studied reactions, the optimal conditions for obtaining the target product have been shown. As a result of a comparative analysis of the results obtained for the synthesis of new isonicotinic hydrazones, it was determined that the use of microwave irradiation contributed to an increase in the yield of the product and a decrease in the reaction time by 3-4 times than according to traditional technology. The authenticity of each product is unambiguously proved by comparing the melting point, as well as by analyzing the physico-chemical characteristics with previously synthesized hydrazone derivatives of isonicotinic acid obtained by classical synthesis methods. The structure of all synthesized compounds was studied by 1H and 13C NMR spectroscopy, as well as data from two-dimensional COSY (1H-1H) spectra and HMQC (1H-13C). The developed microwave method for the synthesis of hydrazone derivatives of isonicotinic acid complies with the principles of the concept of «Green Chemistry».