p-Toluenesulfonic acid → N-(alpha-cyclopropylbenzyl)-N-propylamine

Participants

Reaction Conditions

Reaction Steps

4 Å molecular sieves and 100 mg of para-toluenesulphonic acid are added to 10 g of cyclopropyl phenyl ketone in 60 ml of anhydrous toluene, followed by 6 g of propylamine. Imine formation is monitored by gas chromatographic assay. After heating for 6 hours at 55° C., the reaction mixture is cooled, the molecular sieves are filtered off and the solution is evaporated to dryness under vacuum. The residue is taken up in 100 ml of anhydrous ethanol. The solution is cooled to 0° C. and 2.65 g of sodium borohydride are added portionwise. After stirring overnight at room temperature, the mixture is evaporated to dryness under vacuum and the residue is taken up in water, hydrolysed with 1N hydrochloric acid in order to bring the pH to 2, and washed with ethyl acetate. The pH is brought to 9 by addition of 2N sodium hydroxide and the mixture is then extracted several times with methylene chloride.

Provenance & Evidence