Improved Synthesis of New α-Aminophosphonic Acids by Sonochemical Activation

Abstract

In order to evaluate the biological properties of new α-aminophosphonic acids 4a-g bearing a pyrrolic or thiophenic moiety, their synthesis via the corresponding esters 3a-g is carried out by two methods. The standard procedure leading to α-aminophosphonic esters 3 in good yields, requires heating of the neat reactants for several days. The sonochemical activation improves substantially the rate of formation of 3 and promotes the yields of the reaction. The rate enhancement for this homogeneous sonochemical reaction depends upon the temperature, the nature of the solvent, and the structure of the imine