Synthesis of aminomethylenediphosphonates and their derivatives containing PCNH2 fragments

Abstract

Aminomethylenediphosphonic acids containing free amino group are of interest as promising ligands and biologically active substances with diverse properties [1]. We recently developed several convenient methods for the synthesis of N-substituted aminomethylenediphosphonates starting from Nsubstituted formamides and imines [2]. For the synthesis of new trimethylsilyl-containing aminomethylenediphosphonates and their derivatives with PCNH2 fragments we studied the interaction of tris(trimethylsilyl)phosphate with easily accessible hydrochlorides of substituted ethoxymethyleneimines A [3] in the presence of trimethylsilyl trifluoromethanesulfonate as a catalyst. Thus, substituted ethoxymethyleneimines hydrochlorides A reacted with an excess of tris(trimethylsilyl)phosphite in methylene chloride under mild conditions to form diphosphonates I–III with good yields. DOI: 10.1134/S1070363214030347