N-3-Bromopropylphthalimide → Diethyl (3-aminopropyl)phosphonate

Participants

Reaction Conditions

Reaction Steps

70 ml of triethyl phosphite was added to 40 g of N-(3-bromopropyl)phthalimide (7). The mixture was heated to a temperature of 140° C. The by-produced ethyl bromide was distilled off. The system was then heated over 4 hours. Excess triethyl phosphite was distilled off under reduced pressure by an aspirator. 9 ml of ethanol and hydrazine hydrate were added to the concentrated solution. The system was heated under reflux over 20 minutes. The resulting crystals were filtered off. A mixture of 10 g of oxalic acid and 50 ml of acetone were added to the filtrate. The resulting crystals were filtered off. The filtrate was concentrated. A small amount of water and acetone were added to the residue. The resulting crystals were filtered off. The filtrate was cooled to deposit crystals of oxalic acid salt of diethyl 3-aminopropylphosphonate (8). The crystals were filtered and dried under reduced pressure by a vacuum pump to obtain 12 g of diethyl 3-aminopropylphosphonate (8) in the form of oxalate. (Yield: 34 %; m.p. 54° C.)

Provenance & Evidence