Acetamide → 2-Aminophosphono-acetic acid monohydrate

Participants

Reaction Conditions

Reaction Steps

A solution of 11.8 parts by weight of acetamide, 16.4 parts by weight of orthophosphorus acid in 40 parts by volume of acetic anhydride are heated with stirring to 45° C. To this solution is added, portionwise, 22.2 parts by weight of glyoxylic acid hydrate over 15 minutes. The reaction temperature increases to 80° C., during the addition and this temperature is maintained by external heating for a further 3 hours. The acetic anhydride is removed by distillation, in vacuo, and the viscous residue dissolved in 100 parts by volume concentrated hydrochloric acid. This solution is heated to reflux for 4 hours, then evaporated to dryness to give a brown crystalline solid, which on dissolution in 600 parts by volume of 60% aqueous methanol, followed by addition of propylene oxide, gives 9.3 parts by weight of 2-aminophosphono-acetic acid monohydrate melting at 195° C. with decomposition and having the following elemental analysis by weight:

Provenance & Evidence