aminophosphonate

Aminophosphonates are a class of organophosphorus compounds in which a phosphonate group is directly linked to a carbon atom bearing an amino group. The canonical motif is the α-aminophosphonate, with the general formula R-CH(NH2)-P(=O)(OR)2, making them structural analogs of α-amino acids and phosphate esters. Because of the C–P bond, the phosphonate moiety is typically more resistant to hydrolysis than a phosphate ester, and the compounds can exist as diesters or as the free phosphonic acid.

Most aminophosphonates are prepared by three-component condensations such as the Kabachnik–Fields reaction, involving an aldehyde or ketone, an amine, and a dialkyl phosphite to give α-aminophosphonates. Another route is the Pudovik reaction, in which a phosphite adds to an imine. Diester derivatives are common in synthesis and can be hydrolyzed to the corresponding phosphonic acids.

Applications include use as enzyme inhibitors and ligands in medicinal chemistry, where the phosphonate mimics the tetrahedral geometry of phosphate during enzymatic catalysis. Glyphosate (N-(phosphonomethyl)glycine) is a well-known aminophosphonate used as an herbicide; aminophosphonates also serve as precursors to bioactive molecules and as research tools. One simple example is aminomethylphosphonic acid (AMPA).

Chemically, aminophosphonates are polar, often exist as salts, and display acidity due to the phosphonic acid moiety. They are typically characterized by NMR and mass spectrometry, and their chemistry is a part of phosphorus–carbon bond-forming methods in organophosphorus chemistry.