IMPROVED SYNTHESIS OF NEW ALPHA-AMINOPHOSPHONIC ACIDS BY SONOCHEMICALACTIVATION

In order to evaluate the biological properties of new alpha-aminophosp honic acids 4a-g bearing a pyrrolic or thiophenic moiety, their synthe sis via the corresponding esters 3a-g is carried out by two methods. T he standard procedure leading to alpha-aminophosphonic esters 3 in goo d 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.