(2Z)-3-Aminoprop-2-enal

synthetische3-Aminoacrolein is highly reactive towards self-condensation and is best when freshly prepared. One method of preparation involves the reaction of Ammonia with Propargyl Aldehyde (propynal) in the presence of ethanol in a sealed tube. This method is somewhat erratic, propargaldehyde is not commercially available, and the stereochemistry of the resulting double bond is most likely trans. A modified route, proceeding through 1,1,3,3-tetraethoxypropane, has also been reported. The most satisfactory preparation of β-aminoacrolein involves the partial hydrogenation of isoxazole.3,4 A solution of commercially available isoxazole (5 g, 0.073 mol) in anhyd MeOH (100 mL) containing 1.0 g of Raney Nickel was hydrogenated at 40 psi until one equivalent of hydrogen had been absorbed and hydrogen uptake had ceased (eq 1). The mixture was filtered to remove the catalyst and the solvent was evaporated to give 4.2 g (82%) of a yellow solid, mp 96-97 °C. Recrystallization from chloroform-petroleum ether (1:1) gave crystals, mp 104-105 °C.