The acidic cleavage of pyridylmethyl(amino)phosphonates. Formation of the corresponding amines

Article abstract of DOI:10.1016/0040-4020(96)00727-2

Hydrolysis of 3-pyridylmethyl(amino)phosphonates by means of 20% aq. hydrochloric acid gave corresponding 3-pyridimethyl(amino)phosphonic acids, as expected. However, hydrolysis of 2- and 4-pyridylmethyl(amino)phosphonates led to decomposition of the phosphonates with a cleavage of C-P bond and formation of the corresponding amines. The leaving phosphorus moiety was identified as phosphoric acid. The scope of the reaction is limited to 2- and 4-pyridylmethyl derivatives of aminophosphonic acids and their esters, as well as to the derivatives possessing similar structure. On the contrary, the basic hydrolysis of 2- and 4-pyridylmethyl(amino)phosphonates led to the corresponding monoalkyl esters of the aminophosphonates, and no cleavage of C-P bond was observed in those cases.