Preparation of new imidazol-2-yl-(amino)methylphosphonates, phosphinates and phosphine oxides and their unexpected cleavage under acidic conditions

The efficient synthesis of new imidazol-2-yl-(amino)methylphosphonic acids, phosphonates phosphinate esters and phosphine oxides is described. The synthetic methodology is based on nucleophilic addition of phosphorus species to imidazole-2 derived imines. Additionally, it was discovered that heating the imidazol-2-yl-(amino)methylphosphonates with aqueous HCl or H2SO4 leads to their decomposition resulting in a rupture of the C–P bond, elimination of the phosphorous-containing fragment and formation of the corresponding secondary imidazole-2 alkylamines. A mechanistic pathway for the cleavage is postulated.