Hydrochloric Acid → ethyl (1R,2S)-2-((3S)-3-Benzyloxycarbonylamino-2-oxo-pyrrolidin-1-yl)-5-oxo-cyclohexanecarboxylate

Participants

Reaction Conditions

Reaction Steps

Example 1, Alternative Step 9d: Pyrrolidinone 4 (50.0 g, 0.11M) was dissolved in acetone (500 mL) and 1N HCl (500 mL) was added. The reaction mass was then heated to 65° C. After 20 mins HPLC indicated complete reaction. The reaction mass was allowed to cool to RT and the acetone was removed on a rotary evaporator. During this distillation the product precipitated from solution as a white solid. This was isolated by filtration and the cake washed with water. The cake was then dried azeotropically with toluene (3×300 mL) to give ethyl (1R,2S)-2-((3S)-3-Benzyloxycarbonylamino-2-oxo-pyrrolidin-1-yl)-5-oxo-cyclohexanecarboxylate 5 as a white solid (39.8 g, 88%, 97 area-% purity). 1H-NMR: (300 MHz, CDCl3) δ 7.37-7.32 (m, 5H), 6.65 (br d, J 4.0 Hz, 1H), 5.12 (s, 2H), 4.54-4.47 (m, 1H), 4.34-4.26 (m, 1H), 4.18 (dq, J 11.0 Hz, 7.0 Hz, 1H), 4.09 (dq, J 11.0 Hz, 7.0 Hz, 1H), 3.36-3.20 (m, 3H), 2.70-2.35 (m, 6H), 2.05-1.96 (m, 1H), 1.81 (quin., J 11.0 Hz, 1H), 1.24 (t, J 7.0 Hz, 3H). HPLC: YMC-Pack Pro C18 5 μm 4.6×150 mm, 0.05% TFA (20% MeOH, 80% H2O), to 0.05% TFA (20% MeOH, 80% MeCN), 0-100% 10 min gradient. 8.95 min (Compound 5). HRMS: m/z 403.1864 [Calc: C21H27N2O6 403.1869].

Provenance & Evidence