Acetamide → (1-Aminoethylidene)bisphosphonic acid

Participants

Reaction Conditions

Reaction Steps

83.6 g (1.416 mols) acetamide was dissolved at about 40° C. in 45.4 g (1.1 mols) acetonitrile in a flask which was provided with a stirrer and had a fractionating column mounted thereon. Next, 52 g (0.236 mol) P4O6 was added dropwise at 40°-55° C. After this had been done, the temperature of the reaction mixture was gradually increased to 163° C. while 85.4 g distillate containing 96.4% acetonitrile and 3.5% acetic acid, corresponding to 82.3 g (2.008 mols) acetonitrile and 3.0 g (0.05 mol) acetic acid, was removed at a head temperature of 81°-85° C. After deduction of the acetonitrile feed material, 36.9 g (0.908 mol) acetonitrile was found to have been formed as a by-product. The yellow residue retained in the flask was oxidized with H2O2 and boiled in an ethanol/water-mixture (4:1). 60.1 g colorless crystalline 1-aminoethane-1,1-diphosphonic acid, corresponding to a yield of 60%, was obtained.

Provenance & Evidence