Synthesis of aminophosphonic acids containing carboxyl groups

Abstract

In this research three new aminophosphonic acids containing carboxyl group have been synthesized and characterized. The amino acids are: aminophosphonoacetic acid, 4-amino-phosphonobutyric acid, and 5-amino-5-phosphonopentanonic acid. Aminophosphonoacetic acid was prepared by reduction of the corresponding oximino compound the rest of the amino acids were prepared from their related carboxylate esters via the Curtius Reaction. Five new carboxylate esters and related compounds were prepared. All new compounds were characterized by conventional methods, such as ir and nmr spectrometry, elemental analysis, potentiometric titration, etc. The reaction between hydrazine and some cyanophosphonoalkanoate esters was studied. Surprisingly the reaction between hydrazine and diethyl cyanophosphonoacetate resulted in the loss of the phosphonate ester group. Another surprising result was the loss of the acetyl group when diethyl 2-phosphonoacetoacetate was treated with hydrazine. The catalytic hydrogenation of 1-oximinophosphonate esters was not successful. The reduction was achieved with aluminum amalgam and alcohol.