Acetone → 1-Benzhydrylamino-2-methylpropanephosphonous acid

Participants

Reaction Steps

Diphenylmethylamine (34 mL, 0.2 mol) was added dropwise to a solution of 100% hypophosphorous acid (13.2 g, 0.2 mol) in 100 mL of absolute ethanol. The resulting mixture was stirred at ambient temperature for 15 minutes, then diluted with 500 mL of ether. The precipitated salt (45 g) was collected by filtration. The salt (25 g, 0.1 mol) was dissolved in 50 mL of absolute ethanol and the isopropanal (9 mL, 0.1 mol) (a compound of formula (Xb)) was added. The reaction mixture was heated at reflux for 3 hours. On cooling, the product formed as a precipitate. The product was removed by filtration and washed with ethanol and ether to afford 1-(diphenylmethylamino)-2-methylpropylphosphonous acid (a compound of formula (Xc)) as a white solid (12.5 g) that was used in the next step without further purification.

Provenance & Evidence