Synthesis
The general procedure for the synthesis of N1,N1-dipropylethane-1,2-diamine from dipropylaminoacetonitrile is as follows: a solution of dipropylaminoacetonitrile (3.87 g, 27.6 mmol, 1 eq.) in anhydrous ether (50 mL) was added slowly and dropwise to an anhydrous ethyl ether solution of lithium aluminium hydroxide (1 M, 20 mL, 20.0 mmol, 0.7 eq.) at -78 °C and under nitrogen protection. . The reaction mixture was gradually warmed to room temperature and stirred continuously for 4 hours. Subsequently, the excess lithium aluminum hydride was hydrolyzed using the Mihailovic method [4]. After completion of the reaction, the precipitate was collected by filtration and washed with ether (3 x 10 mL). The organic layers were combined, dried with magnesium sulfate and concentrated under reduced pressure to afford N1,N1-dipropylethane-1,2-diamine (compound 6) as a yellow oil (6.24 g, 27.6 mmol, 99% yield). Thin layer chromatography (TLC) analysis showed an Rf value of 0.2 (silica gel, eluent B). Nuclear magnetic resonance hydrogen spectroscopy (1H NMR, CDCl3, 200 MHz) data were as follows: δ 0.61 (triple peak, 6H, J = 7.5Hz, H5), 1.18 (multiple peaks, 4H, J = 7.5Hz, H4), 1.34 (single peak, 2H, NH2), 2.09 (triple peak, 4H, J = 7.5Hz, H3), 2.18 (triple peak. 2H, J = 6Hz, H2), 2.44 (triple peak, 2H, J = 6Hz, H1). The nuclear magnetic resonance carbon spectrum (13C NMR, CDCl3, 50.3 MHz) data were as follows: δ 11.6 (2C5), 20.2 (2C4), 39.6 (C1), 56.1 (2C3), 56.9 (C2).
References
[1] European Journal of Medicinal Chemistry, 2011, vol. 46, # 11, p. 5705 - 5710
[2] Bulletin de la Societe Chimique de France, 1962, p. 556 - 558
