Propylene Oxide → 3-Aminopropyl(propargyl)-phosphinic acid

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Reaction Steps

A suspension of 1,23 g (10 mmol) of 3-aminopropylphosphonous acid in 10.4 ml (50 mmol) of hexamethyldisilazane is heated to reflux under argon for 24 hours. 5 ml of diethylene glycol dimethyl ether are added to the clear solution obtained and the mixture is heated for additional 2 hours and then cooled to 0°. 8.5 ml (50 mmol) of N-ethyl-N,N-diisopropyl-amine are added, followed by slow addition of 3.8 ml (50 mmol) of propargyl bromide over a period of 40 minutes. The mixtureis stirred for 1 hour at 0° and 4 hours at room temperature, filtered and evaporated under high vacuum. The residue is dissolved in 10 ml of dichloromethane and extracted with 3×10 ml of 1N hydrochloric acid solution. The water layer is evaporated under high vacuum and the residue obtained dissolved in 4 ml of methanol at 0°. 20 ml of propylene oxide are added during a period of 1 hour, after which time a crude product precipitates. Chromatography (silicagel Merck 230-400 ASTM, methanol) followed by recrystallization (methanol/ether) yields 3-aminopropyl(propargyl)-phosphinic acid, m.p. 172°-173°.

Provenance & Evidence