Trifluoroacetic acid → Benzyl (S)-1-((1S,2R,4R)-2-acetamido-4-aminocyclohexyl)-2-oxopyrrolidin-3-ylcarbamate

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Reaction Steps

A stirring solution of tert-butyl (1R,3R,4S)-3-acetamido-4-((S)-3-(benzyloxycarbonylamino)-2-oxopyrrolidin-1-yl)cyclohexylcarbamate (66 g, 0.135 mol; see Example 1, Step 6) in dichloromethane (216 mL) was charged with trifluoroacetic acid (216 mL). The reaction was stirred for 2 h at room temperature and concentrated in vacuo. The residue was dissolved in methanol and the resultant solution was concentrated in vacuo; this was repeated once. Benzyl (S)-1-((1S,2R,4R)-2-acetamido-4-aminocyclohexyl)-2-oxopyrrolidin-3-ylcarbamate was obtained as an oil. LC/MS found [M+H]+=389.4. 1H-NMR (400 MHz, d-MeOH): δ 7.3-7.4 (m, 5H), 5.12 (s, 2H), 4.41 (br. s, 1H), 4.15 (m, 1H), 4.00 (t, J=9.3 Hz, 1H), 3.81 (t, J=9.1 Hz, 1H), 3.65 (q, J=8.4 Hz, 1H), 3.3-3.4 (m, 1H), 2.45 (m, 1H), 1.95-2.24 (m, 5H), 2.00 (s, 3H), 1.6-1.8 (m, 2H).

Provenance & Evidence