(3S)-3-[(2S)-2-Amino-4-chloro-3-oxobutyl]pyrrolidin-2-one, Hydrochloride Salt (10)
A solution of tert-butyl ((1S)-3-diazo-2-oxo-1-{[(3S)-2-oxopyrrolidin-3-yl]methyl}propyl) carbamate (592 mg, 2.0 mmol) in 1,4-dioxane (7 mL) was placed under an atmosphere of N2 and cooled to 0 °C. This clear pale yellow solution was dropwise treated with a solution of 4 M hydrochloric acid in 1,4-dioxane (5 mL, 20 mmol) with copious gas evolution observed. Upon complete addition, the reaction was warmed to RT over 1 h with the formation of a white precipitate. The solid was collected by filtration, washed with diethyl ether, and dried to give 401 mg (83%) of the title compound as a white powder. 1H NMR (DMSO-d6) δ 8.76 (bs, 3H), 7.96 (s, 1H), 4.93 (d, J = 16 Hz, 1H), 4.80 (d, J = 16 Hz, 1H), 4.28 (m, 1H), 3.18 (m, 2H), 2.61 (m, 1H), 2.30 (m, 1H), 1.93 (m, 2H), 1.70 (m, 1H); MS (ESI+) for C8H13ClN2O2m/z 205.0 (M + H)+.