Cyanogen Bromide → N-(2,2-diethoxyethyl)carbodiimide

A solution of the aminoacetaldehyde diethyl acetal (13.16 g, 99 mmol) in ether (35 mL) was added to a suspension of CNBr (10.47 g, 99 mmol) in hexane (35 mL) at room temperature. The reaction mixture was stirred at room temperature overnight. The solid was removed by filtration and washed with ether. The combined filtrate was concentrated. Purification by column chromatography (silica gel, eluting with dichloromethane to 4% methanol in dichloromethane, gradient) afforded the title compound (7.0 g, 44.7%, one half of the starting amine served as a sacrificial base in the reaction) (Rf: 2.70, 4% methanol in dichloromethane, stain with 10% ethanolic molybdatophosphoric acid). 1H NMR 400 MHz (CDCl3) δ 4.58 (t, J=5.2 Hz, 1H), 3.77-3.69 (m, 2H), 3.65 (br, s, 1H), 3.60-352 (m, 2H), 3.16 (t, J=5.6 Hz, 1H), 1.23 (t, 6H, J=6.8 Hz).