127828-22-2

176220-30-7

127828-22-2

Step 4: Synthesis of tert-butyl [2-(2-aminoethoxy)ethyl]carbamate (58) Under argon protection, tert-butyl (2-(2-azidoethoxy)ethyl)carbamate (57, 5.0 g, 0.0217 mol) was dissolved in methanol (100 mL) and palladium/carbon catalyst (2.5 g, 10 mL) was added. The reaction mixture was stirred overnight at room temperature under hydrogen (50 psi) atmosphere. Upon completion of the reaction, the catalyst was removed by filtration through a diatomaceous earth pad and the filtrate was concentrated under reduced pressure to afford tert-butyl [2-(2-aminoethoxy)ethyl]carbamate (58, 3.0 g). The resulting product can be used directly in the subsequent reaction without further purification. 1H NMR (400 MHz, MeOD) δ 3.48-3.45 (m, 4H), 3.23-3.20 (t, 2H), 2.77-2.75 (m, 2H), 1.43 (s, 9H).