Sodium hydride → (R)-tert-butyl 4-benzyl-2-isopropyl-3-oxopiperazine-1-carboxylate

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Reaction Steps

To a solution of (R)-tert-butyl(1-(benzyl(2-chloroethyl)amino)-3-methyl-1-oxobutan-2-yl)carbamate (2.0 g, 5.40 mmol) in DMF (30 mL) was added NaH (1.0 g, 27.0 mmol, 60% in oil mineral) at 0° C. under N2. The mixture was stirred at rt for 2 h. The mixture was quenched with water (20 mL) and extracted with EtOAc (3×20 mL). The combined organic layers were washed with brine (20 mL) and dried over anhydrous Na2SO4, filtered, concentrated and purified by column chromatography to afford (R)-tert-butyl 4-benzyl-2-isopropyl-3-oxopiperazine-1-carboxylate (1.13 g, 63% yield) as a white solid. LC-MS m/z 277.1 [M−56+H]+. 1H NMR (CDCl3 400 MHz): δ 7.38-7.29 (m, 3H), 7.29-7.22 (m, 2H), 5.02-4.86 (m, 1H), 4.49-4.39 (m, 1H), 4.31-4.06 (m, 2H), 3.41-3.18 (m, 3H), 2.42-2.31 (m, 1H), 1.46 (s, 9H), 1.12 (d, J=6.8 Hz, 3H), 1.00 (d, J=6.8 Hz, 3H).

Provenance & Evidence