Ethanolamine → 1-(2-Hydroxyethyl)-3,3-dimethylpiperazine-2,5-dione

A solution of methyl 2-(2-chloroacetamido)-2-methylpropanoate (2.5 g, 13 mmol), ethanolamine (1.3 g, 21.3 mmol), and N,N-diisopropylethylamine (4.0 mL, 23 mmol) in 250 mL of anhydrous tetrahydrofuran was heated at reflux temperature for 24 hours. The mixture was concentrated to a residue in vacuo and dissolved in ethanol (approximately 300 mL). The mixture was heated in a sealed tube at 155° C. for 24 hours then concentrated to a crude residue and purified by column chromatography (5 to 12% methanol in dichloromethane) to give the title compound as a white solid (1.03 g, 5.5 mmol, 42%). 1H NMR (DMSO-d6, 400 MHz) δ 1.30 (s, 6H), 3.32-3.35 (t, J=5.7, 2H), 3.48-3.53 (q, J=5.7, 2H) 4.02 (s, 2H), 4.75-4.77 (t, J=5.4 Hz, 1H). LRMS (ESI/APCI) m/z 187 [M+H]+.