SYNTHESIS OF SYMMETRICAL METHYLENEBIS(ALKYL HYDROGEN PHOSPHONATES) BY SELECTIVE CLEAVAGE OF METHYLENEBIS(DIALKYL PHOSPHONATES) WITH MORPHOLINE.

The preparation of partial esters of methylenebisphosphonic acids has been of recent interest due to their potential therapeutic applications. This paper describes a convenient method to prepare symmetrical methylenebis(alkyl hydrogen phosphonates) by the selective cleavage of the corresponding methylenebis(dialkyl phosphonate) with refluxing morpholine. The effects of structural variations on the amine as well as the substrate have been investigated to understand the scope and limitations of this reaction.