Novel α-aminophosphonic acids are synthesized reacting 1, 3-oxazolidin-2-one derivatives with formaldehyde and phosphorus trichloride. Treatment of N-(phosphonomethyl) oxazolidinones with aqueous NaOH gave the expected α-aminophosphonic acids. The oxidation of (2-hydroxy-1, 1-dimethylethylamino) methyl phosphonic acid in the presence of CdO and water resulted in N-phosphonomethyl-2-methyl-1-propanoic acid. Their ...